Information

Are we more/less resistant to infectious diseases during an allergic reaction?


To my understanding, an allergic response is a non-adaptive response of the immune system to some molecule. The molecule in question is therefore "thought by the immune system" to be infectious although it is not. An allergic response is triggered by immunoglobulin of type E ($IG_E$) and causes an immune reaction.

I'd expect immune responses to not be instataneous, that is I would expect that it takes some time in order for the immune system to achieve some reaction peak. In consequences, I have been wondering whether someone that is under an allergic reaction is more resistant to early development of infectious disease because the immune system is already "switched on" prior to the infection. On the other hand, I would have thought that the body resistance to anything is lowered during an allergic reaction 1) because the allergy diminishes "general health" and 2) because allergic response may kill body cells.

Are we more/less resistant to infectious diseases during an allergic reaction?


There are a number of issues with your question, and the short answer is no.

Immunity to pathogens is conferred by antibodies, but not usually of the IgE group. Pathogens usually stimulate IgM -> IgG; IgAs are present in mucosal surfaces.

There are multiple kinds of "allergic responses", and each carries its own risks.

  • Type I reactions (ie, immediate hypersensitivity reactions) involve immunoglobulin E (IgE)-mediated release of histamine and other mediators from mast cells and basophils.
  • Type II reactions (ie, cytotoxic hypersensitivity reactions) involve immunoglobulin G or immunoglobulin M antibodies bound to cell surface antigens, with subsequent complement fixation.
  • Type III reactions (ie, immune-complex reactions) involve circulating antigen-antibody immune complexes that deposit in postcapillary venules, with subsequent complement fixation.
  • Type IV reactions (ie, delayed hypersensitivity reactions, cell-mediated immunity) are mediated by T cells rather than by antibodies.

Limiting ourselves to allergic responses mediated by IgE, we have anaphylaxis, allergic asthma, urticaria, angioedema, allergic rhinitis, some types of drug reactions, and atopic dermatitis. These reactions can result in something as mild as urticaria or as life-threatening as anaphylaxis. None of these conditions carries an increased or decreased general immunological response to pathogens.

If allergy affected immunocompetency, one would expect to see, for example, an increased incidence of fungal infections in allergic individuals, but this is not the case. Allergy does not result in an immunocompromised condition, nor does it result in a primed response (an idea popular in the 90's). They are mediated by different pathways.

Effector mechanisms in allergic reactions
The production of IgE
Allergy, Parasites, and the Hygiene Hypothesis
Immunocompetence and allergy


This is a very good question which is an active research topic! I can just say that we do not know the correct answer to it but we have some evidences that some allergies are connected with autoimmune diseases. You called this

1) the allergy diminishes "general health" and 2) because allergic response may kill body cells.

I would say that there can be a mechanism between allergies and autoimmune diseases.

  • IgE Mediated allergy to wheat in a child with celiac disease. There has been later found other cases on this but not published in PubMed. The link between coeliac disease and IgE-mediated allergy is not very clear. Pharmacological intervention with Montelukast (a leukotriene-antagonist) can possibly in all sorts of ways. However, research is going on about this because the mechanism is unknown.

I picked celiac disease here because it is been connected to many other autoimmune diseases and is the most undiagnosed disease. I consider Montelukast because its mechanism in IgE and because of its latest research findings with childhood asthma (about 2001), see this search in PubMed, and in successful treatment of opportunistic diseases in HIV/AIDS, see this publication.


  • The most common form of artificial immunity is classified as active and comes in the form of vaccinations, typically given to children and young adults.
  • The passive form of artificial immunity involves introducing an antibody into the system once a person has already been infected with a disease, ultimately relieving the present symptoms of the sickness and preventing re-occurrence.
  • Once the body has successfully rid itself of a disease caused by a certain pathogen, a second infection with the same pathogen would prove harmless.
  • gamma globulin: a class of proteins in the blood, identified by their position after serum protein electrophoresis, such as antibodies
  • anaphylactic shock: A severe and rapid systemic allergic reaction to an allergen, constricting the trachea and preventing breathing.
  • herd immunity: the protection given to a community against an epidemic of a contagious disease when a sufficient number of the population are immunised or otherwise develop immunity to it

Immunity is the state of protection against infectious disease conferred either through an immune response generated by immunization or by previous infection or other non-immunological factors.

Artificial immunity can be active or passive.

Figure: Immunity: Natural immunity occurs through contact with a disease causing agent, when the contact was not deliberate, where as artificial immunity develops only through deliberate actions of exposure. Both natural and artificial immunity can be further subdivided, depending on the amount of time the protection lasts. Passive immunity is short lived, and usually lasts only a few months, whereas protection via active immunity lasts much longer, and is sometimes life-long.

Artificially-acquired passive immunity is an immediate, but short-term immunization provided by the injection of antibodies, such as gamma globulin, that are not produced by the recipient&rsquos cells. These antibodies are developed in another individual or animal and then injected into another individual. Antiserum is the general term used for preparations that contains antibodies.

Artificial active immunization is where the microbe, or parts of it, are injected into the person before they are able to take it in naturally. If whole microbes are used, they are pre-treated, attenuated vaccines. This vaccine stimulates a primary response against the antigen in the recipient without causing symptoms of the disease.

Artificial passive immunization is normally administered by injection and is used if there has been a recent outbreak of a particular disease or as an emergency treatment for toxicity, as in for tetanus. The antibodies can be produced in animals, called &rdquo serum therapy,&rdquo although there is a high chance of anaphylactic shock because of immunity against animal serum itself. Thus, humanized antibodies produced in vitro by cell culture are used instead if available.

The first record of artificial immunity was in relation to a disease known as smallpox. Individuals were exposed to a minor strain of smallpox in a controlled environment. Once their bodies built up a natural immunity or resistance to the weakened strain of smallpox, they became much less likely to become infected with the more deadly strains of the disease. In essence, patients were given the disease in order to help fight it later in life. Although this method was an effective one, the scientists of the time had no real scientific knowledge of why it worked.


SKIN EXPOSURES & EFFECTS

It is estimated that more than 13 million workers in the United States are potentially exposed to chemicals that can be absorbed through the skin. Dermal exposure to hazardous agents can result in a variety of occupational diseases and disorders, including occupational skin diseases (OSD) and systemic toxicity. Historically, efforts to control workplace exposures to hazardous agents have focused on inhalation rather than skin exposures. As a result, assessment strategies and methods are well developed for evaluating inhalation exposures in the workplace standardized methods are currently lacking for measuring and assessing skin exposures.

NIOSH has developed a strategy for assigning multiple skin notations (SK) capable of delineating between the systemic, direct and immune-mediated effects caused by dermal contact with chemicals.

OSD are the second most common type of occupational disease and can occur in several different forms including:

  • Irritant contact dermatitis,
  • Allergic contact dermatitis,
  • Skin cancers,
  • Skin infections,
  • Skin injuries, and
  • Other miscellaneous skin diseases.

Contact dermatitis is one of the most common types of occupational illness, with estimated annual costs exceeding $1 billion.

Occupations at Risk

Workers at risk of potentially harmful exposures of the skin include, but are not limited to, those working in the following industries and sectors:

  • Food service
  • Cosmetology
  • Health care
  • Agriculture
  • Cleaning
  • Painting
  • Mechanics
  • Printing/lithography
  • Construction

Anatomy and Functions of the Skin

The skin is the body&rsquos largest organ, accounting for more than 10 percent of body mass. The skin provides a number of functions including:

  • protection,
  • water preservation,
  • shock absorption,
  • tactile sensation,
  • calorie reservation,
  • vitamin D synthesis,
  • temperature control, and
  • lubrication and waterproofing.

Skin Hazards

Causes of OSD include chemical agents, mechanical trauma, physical agents, and biological agents.

  • Chemical agents are the main cause of occupational skin diseases and disorders. These agents are divided into two types: primary irritants and sensitizers. Primary or direct irritants act directly on the skin though chemical reactions. Sensitizers may not cause immediate skin reactions, but repeated exposure can result in allergic reactions.
    • A worker&rsquos skin may be exposed to hazardous chemicals through:
      • direct contact with contaminated surfaces,
      • deposition of aerosols,
      • immersion, or
      • splashes.

      Dermal Absorption

      Dermal absorption is the transport of a chemical from the outer surface of the skin both into the skin and into the body. Studies show that absorption of chemicals through the skin can occur without being noticed by the worker, and in some cases, may represent the most significant exposure pathway. Many commonly used chemicals in the workplace could potentially result in systemic toxicity if they penetrate through the skin (i.e. pesticides, organic solvents). These chemicals enter the blood stream and cause health problems away from the site of entry.

      The rate of dermal absorption depends largely on the outer layer of the skin called the stratum corneum (SC). The SC serves an important barrier function by keeping molecules from passing into and out of the skin, thus protecting the lower layers of skin. The extent of absorption is dependent on the following factors:

      • Skin integrity (damaged vs. intact)
      • Location of exposure (thickness and water content of stratum corneum skin temperature)
      • Physical and chemical properties of the hazardous substance
      • Concentration of a chemical on the skin surface
      • Duration of exposure
      • The surface area of skin exposed to a hazardous substance

      Research has revealed that skin absorption occurs via diffusion, the process whereby molecules spread from areas of high concentration to areas of low concentration. Three mechanisms by which chemicals diffuse into the skin have been proposed:

      1. Intercellular lipid pathway (Figure 1)
      2. Transcellular permeation (Figure 2)
      3. Through the appendages (Figure 3)

      Figure 1: Intercellular lipid pathway

      As shown in Figure 1, the stratum corneum consists of cells known as corneocytes. The spaces between the corneocytes are filled with substances such as fats, oils, or waxes known as lipids. Some chemicals can penetrate through these lipid-filled intercellular spaces through diffusion.

      Figure 2: Transcellular permeation

      As shown in Figure 2, another pathway for chemicals to be absorbed into and through the skin is transcellular, or cell-to-cell, permeation whereby molecules diffuse directly through the corneocytes.

      Figure 3: Through the appendages (hair follicles, glands)

      As shown in Figure 3, the third pathway for diffusion of chemicals into and through the skin is skin appendages (i.e., hair follicles and glands). This pathway is usually insignificant because the surface area of the appendages is very small compared to the total skin area. However, very slowly permeating chemicals may employ this pathway during the initial stage of absorption.

      Contact Dermatitis

      Contact dermatitis, also called eczema, is defined as an inflammation of the skin resulting from exposure to a hazardous agent. It is the most common form of reported OSD, and represents an overwhelming burden for workers in developed nations. Epidemiological data indicate that contact dermatitis constitutes approximately 90-95% of all cases of OSD in the United States. Common symptoms of dermatitis include:


      NIH scientists find link between allergic and autoimmune diseases in mouse study

      Scientists at the National Institutes of Health, and their colleagues, have discovered that a gene called BACH2 may play a central role in the development of diverse allergic and autoimmune diseases, such as multiple sclerosis, asthma, Crohn's disease, celiac disease, and type-1 diabetes. In autoimmune diseases, the immune system attacks normal cells and tissues in the body that are generally recognized as “self” and do not normally trigger immune responses. Autoimmunity can occur in infectious diseases and cancer.

      The results of previous research had shown that people with minor variations in the BACH2 gene often develop allergic or autoimmune diseases, and that a common factor in these diseases is a compromised immune system. In this study in mice, the Bach2 gene was found to be a critical regulator of the immune system’s reactivity. The study, headed by researchers at the National Cancer Institute (NCI) and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), both part of NIH, and their colleagues appeared online in Nature, June 2, 2013.

      The finding that a single component of the immune system plays such a broad role in regulating immune function may explain why people with allergic and autoimmune diseases commonly have alterations in the BACH2 gene, said NCI researcher Rahul Roychoudhuri, M.D. "This may be the first step in developing novel therapies for these disorders."

      Studies known as genome-wide association studies, which analyze genetic variants among people to determine whether specific variants are associated with particular traits, were critical to the discovery. These studies showed that DNA from patients with diverse autoimmune disorders often had minor alterations in the BACH2 gene, which laid the foundation for this research.

      “What was exciting was the opportunity to apply cutting-edge technology permitted by the completion of the Human Genome Project,” said NIAMS scientific director John O’Shea, M.D. “Using genome-wide approaches we were able to map the action of Bach2 across all genes. This enabled us to gain a clearer understanding of Bach2’s key role in the immune system.”

      The immune system is comprised of a variety of cell types that must act in unison to maintain a healthy balance. White blood cells called CD4+T cells play a dual role within the immune system. Some CD4+T cells activate immune responses, whereas others, called regulatory T cells, function in the opposite direction by constraining immune responses. This duality is important because uncontrolled immune responses may result in immune system attacks against the body’s own cells and tissues, which occurs in allergic and autoimmune diseases. One of the hallmarks of uncontrolled immune responses is excessive tissue inflammation. Although tissue inflammation is a normal part of immune responses, excessive inflammation can lead to tissue and organ damage and may be potentially lethal. How CD4+T cells become either activating/inflammatory or regulatory is not well understood, according to the researchers.

      “We found that the Bach2 gene played a key role in regulating the switch between inflammatory and regulatory cells in mice,” said NIAMS researcher Kiyoshi Hirahara, M.D. “The loss of the Bach2 gene in CD4+ T cells caused them to become inflammatory, even in situations that would normally result in the formation of protective regulatory cells.”

      The team found that if mice lacked the Bach2 gene their cells became inflammatory and the mice died of autoimmune diseases within the first few months of life. When they re-inserted Bach2 (using gene therapy) into Bach2-deficient cells, their ability to produce regulatory cells was restored.

      "Although genes have been found that play specific roles in either inflammatory cells or regulatory cells, Bach2 regulates the choice between the two cell types, resulting in its critical role in maintaining the immune system’s healthy balance," said NCI principal investigator, Nicholas P. Restifo, M.D., "It’s apt that the gene shares its name with the famous composer Bach, since it orchestrates many components of the immune response, which, like the diverse instruments of an orchestra, must act in unison to achieve symphonic harmony."

      Restifo suggests that these findings have implications for cancer as well, since cancers co-opt regulatory T cells to prevent their own destruction by antitumor immune responses. He and his colleagues are now working toward manipulating the activity of the Bach2 gene, with the goal of developing a new cancer immunotherapy. Also, as this study was in mice, it must be replicated in humans before its findings can be applied in a clinical setting.

      In addition to researchers from NCI and NIAMS, this research was supported by the JSPS Research Fellowship for Japanese Biomedical and Behavioural Researchers at NIH and includes contributions from scientists at the National Institutes of Allergy and Infectious Diseases, NIH the Department of Transfusion Medicine, NIH the Division of Veterinary Resources, NIH the Center for Regenerative Medicine, NIH the Sidra Medical and Research Centre, Doha, Qatar and the Department of Biochemistry, Tohoku University, Sendai, Japan.

      NCI leads the National Cancer Program and the NIH effort to dramatically reduce the burden of cancer and improve the lives of cancer patients and their families through research into prevention and cancer biology, the development of new interventions, and the training and mentoring of new researchers. For more information about cancer, please visit the NCI website at http://www.cancer.gov or call NCI's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).

      The mission of the NIAMS, a part of the U.S. Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment and prevention of arthritis and musculoskeletal and skin diseases the training of basic and clinical scientists to carry out this research and the dissemination of information on research progress in these diseases. For more information about the NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS website at http://www.niams.nih.gov.

      About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

      NIH&hellipTurning Discovery Into Health ®

      Reference

      O’Shea, JJ, Restifo, et al. Bach2 represses effector programmes to stabilize Treg-mediated immune homeostasis. Nature. Online June 2, 2013. DOI: 10.1038/nature12199.


      Multiple Choice Questions
      Single Correct Answer Type

      1. The term ‘Health’ is defined in many ways. The most accurate definition of the health would be
      (a) Health is the state of body and mind in a balanced condition
      (b) Health is the reflection of a smiling face
      (c) Health is a state of complete physical, mental and social well-being
      (d) Health is the symbol of economic prosperity.
      Answer. (c) Health is not just the absence of disease. It is a state of complete physical, mental, social and psychological well-being.

      2. The organisms which cause diseases in plants and animals are called
      (a) Pathogens (b) Vectors (c) Insects (d) Worms
      Answer. (a) A wide range of organisms belonging to bacteria, viruses, fungi protozoans, helminthes, etc., could cause diseases in man. Such disease causing organisms are called pathogens.

      3. The chemical test that is used for diagnosis of typhoid is
      (a) ELISA-Test (b) ESR-Test
      (c) PCR-Test (d) Widal-Test
      Answer. (d) The chemical test that is used for diagnosis of typhoid is Widal-Test.

      4. Diseases are broadly grouped into infectious and non-infectious diseases. In the list given below, identify the infectious diseases.
      i. Cancer ii. Influenza
      iii. Allergy iv. Small pox
      (a) i and ii (b) ii and iii –
      (c) iii and iv (d) ii and iv
      Answer. (d)

      5. The sporozoites that cause infection, when a female Anopheles mosquito bites a person being are formed in
      (a) Liver of person (b) RBCs of mosquito .
      (c) Salivary glands of mosquito (d) Intestine of mosquito
      Answer. (d) The sporozoites that cause infection, when a female Anopheles mosquito bites a person being are formed in intestine of mosquito.

      6. The disease chikunguniya is transmitted by
      (a) House flies (b) Aedes mosquitoes
      (c) Cockroach (d) Female Anopheles
      Answer. (b) Dengue and chikunguniya are transmitted by Aedes mosquitoes.

      7. Many diseases can’be diagnosed by observing the symptoms in the patient. Which group of symptoms are indicative of pneumonia?
      (a) Difficulty in respiration, fever, chills, cough, headache
      (b) Constipation, abdominal pain, cramps, blood clots
      (c) Nasal congestion and discharge, cough, sorethroat, headache
      (d) High fever, weakness, stomach pain, loss of appetite and constipation.
      Answer. (a)

      • Difficulty in respiration, fever, chills, cough, headache: Pneumonia
      • Constipation, abdominal pain, cramps, blood clots: Amoebiasis
      • Nasal congestion and discharge, cough, sorethroat, headache: Common cold
      • High fever, weakness, stomach pain, loss of appetite and constipation: Typhoid

      8. The genes causing cancer are
      (a) Structural genes (b) Expressor genes
      (c) Oncogenes ’ (d) Regulatory genes
      Answer. (c) Oncogenes are the cancer causing genes.

      9. In malignant tumors, the cells proliferate, grow rapidly and move to other . parts of the body to form new tumors. This stage of disease is called
      (a) Metagenesis (b) Metastasis
      (c) Teratogenesis (d) Mitosis
      Answer. (b) In malignant tumors, the cells proliferate, grow rapidly and move to other parts of the body to form new tumors. This stage of disease is called metastasis.

      10. When an apparently healthy person is diagnosed as unhealthy by a psychiatrist, the reason could be that
      (a) The patient was not efficient at his work
      (b) The patient was not economically prosperous
      (c) The patient shows behavioural and social maladjustment
      (d) He does not take interest in sports
      Answer. (c) When an apparently healthy person- is diagnosed as unhealthy by a psychiatrist, the reason could be that the patient shows behavioural and social maladjustment.

      11. Which of the following are the reason(s) for Rheumatoid arthritis? Choose the correct option.
      i. The ability to differentiate pathogens or foreign molecules from self cells increases
      ii. Body attacks self cells
      iii. More afitibodies are produced in the body
      iv. The ability to differentiate pathogens or foreign molecules from self cells is lost
      (a) i and ii (b) ii and iv (c) iii and iv (d) i and iii
      Answer. (b) Rheumatoid arthritis is an autoimmune diseases in which

      • Body attacks self cells
      • The ability to differentiate pathogens or foreign molecules from self cells is lost

      12. AIDS is caused by HIV. Among the following, which one is not a mode of transmission of HIV?
      (a) Transfusion of contaminated blood
      (b) Sharing the infected needles
      (c) Shaking hands with infected persons
      (d) Sexual contact with infected persons
      Answer. (c) Mode of transmission of HIV:

      • Transfusion of contaminated blood
      • Sharing the infected needles
      • Sexual contact with infected persons

      13. ‘Smack’ is a drug obtained fipm the
      (a) Latex of Papaver somniferum (b) Leaves of Cannabis sativa
      (c) Flowers of Datura (d) Fruits of Erythroxylum coca
      Answer. (a)

      • ‘ Smack’ is a drug obtained from the latex of Papaver somniferum.
      • Smack are brown sugar, the common name of Heroin.
      • Heroin is obtained by acetylation of morphine.

      14. The substance produced by a cell in viral infection that can protect other cells from further infection is N
      (a) Serotonin (b) Colostrum
      (c) Interferon (d) Histamine
      Answer. (c) The substance produced by a cell in viral infection that can protect other cells from further infection is interferon.

      15. Transplantation-of tissues/organs to save certain patients often fails due to rejection of such tissues/organs by the patient. Which type of immune response is responsible for such rejections?
      (a) Auto-immune response (b) Humoral immune response
      (c) Physiological immune response (d) Cell-mediated,immune response
      Answer. (d) Transplantation of tissues/organs to-save certain patients often fails due to rejection of such tissues/organs by the patient. Cell-mediated immune response is responsible for such rejections.

      16. Antibodies present in colostrum which protect the new bom from certain diseases is of
      (a) Ig G type (b) Ig A type (c) Ig D type (d) Ig E type
      Answer. (b) Antibodies present in colostrum which protect the new bom from certain diseases is of Ig A type.

      17. Tobacco consumption is known to stimulate secretion of adrenaline and nor¬adrenaline. The component causing this could be
      (a) Nicotine (b) Tannic acid (c) Curaimin (d) Catechin
      Answer. (a) Tobacco consumption is known to stimulate secretion of adrenaline and nor-adrenaline. The component causing this could be nicotine. Morphine, cocaine, codeine and nicotine are all alkaloids.

      18. Anti-venom against’snake poison contains
      (a) Antigens (b) Antigen-antibody complexes
      (c) Antibodies (d) Enzymes
      Answer. (c) Anti-venom against snake poison contains antibodies.

      19. Which of the following is not a lymphoid tissue?
      (a) Spleen (b) Tonsils (c) Pancreas (d) Thymus
      Answer. (c) Spleen, Tonsils and Thymus are lymphoid tissue while pancreas is mixed gland.

      20. Which of the following glands is large sized at birth but reduces in size with ageing?
      (a) Pineal (b) Pituitary (c) Thymus (d) Thyroid
      Answer. (c) Thymus glands is large sized at birth but reduces in size with ageing.

      21. Haemozoin is a
      (a) Precursor of hemoglobin
      (b) Toxin released from Streptococcus infected cells
      (c) Toxin released from Plasmodium infected cells
      (d) Toxin released from Haemophilus infected cells ’
      Answer. (c) Haemozoin is a toxin released from Plasmodium infected cells.

      22. One Of the following is not the causal organism for ringworm.
      (a) Microsporum (b) Trichophyton
      (c) Epidermophyton (d) Macrosporum
      Answer. (d) Microsporum, Trichophyton and Epidermophytonare the causal organism for ringworm while Macrosporum is a brown alga.

      23. A person with sickle cell anemia is
      (a) More prone to malaria (b) More prone to typhoid
      (c) Less prone to malaria (d) Less prone to typhoid.
      Answer. (c) A person with sickle cell anemia is less prone to malaria.

      Very Short Answer Type Questions
      1. Certain pathogens are tissue/organ specific. Justify the statement with suitable examples.
      Answer. Salmonella typhi causes typhoid and infects small intestine while intestinal endoparasite causes amoebic dysentery and infects large intestine.

      2.The immune system of a person is suppressed. In the ELISA test, he was found positive to a pathogen.
      a. Name the disease the patient is suffering from.
      b. What is the causative organism?
      c. Which cells of body are affected by the pathogen?
      Answer. a. Acquired Immuno Deficiency Syndrome (AIDS)
      b. Human Immuno deficiency virus (HIV)
      c. Helper T-lymphocytes (TH or T4)

      3. Where are B-cells and T-cells formed? How do they differ from each other?
      Answer. Both B-cells and T-cells are formed in bone marrow. B-cells matures in bone marrow while T-cells matures in thymus. B-cells provides humoral immunity and T-cells provides cell mediated immunity (CMI).

      4. Given below are the pairs of pathogens and the diseases caused by them. Which out of these is not a matching pair and why?
      (a) Virus – common cold (b) Salmonella – typhoid
      (c) Microsporum – filariasis (d) Plasmodium – malaria
      Answer. Pair is mismatched. Microsporum causes ringworm disease.

      5. What would happen to immune system, if thymus gland is removed from the body of a person?
      Answer. Thymus is the primary lymphoid organ. In thymus gland, immature lymphocytes differentiate into antigen-sensitive lymphocytes. If thymus gland is removed from the body of a person, his immune system becomes weak. As a result the person’s body becomes prone to infectious diseases,

      6. Many microbial pathogens enter the gut of humans along with food. What are the preventive barriers to protect the body from such pathogens? What type of immunity do you observe in this case?
      Answer. (i) The mucus coating of the epithelium lining of the gut helps in trapping microbes entering the body.
      (ii) Saliva in the mouth and hydrochloric acid in gastric juice secreted by stomach prevent microbial growth. This type of immunity is innate immunity.

      7. Why is mother’s milk considered the most appropriate food for a new born infant?
      Answer. Mother’s milk is considered as the most appropriate food for a new born infant because the yellowish fluid colostrum secreted by mother during the initial days of lactation has abundant antibodies (IgA) to protect the infant.

      8. What are interferons? How do interferons check infection of new cells?
      Answer. Interferons are natural proteins produced by the cells of immune system in
      response to foreign agents such as viruses, tumor cells and parasites and protect non-infected cells from further infection. Interferons inhibit the viral replication within host cells, activate natural killer cells and macrophages, increases antigen presentation to lymphocytes, and induce the resistance of host cells to viral infection. When the antigen is presented to matching T-cells’ and B-cells, these cells multiply and remove the foreign substance.

      9. In the figure, structure of an antibody molecule is shown. Name the parts A, B and C. Show A, B and C in the diagram.

      Answer. A:—Constant region of heavy chain,
      B—Constant region of light chain,
      C—Variable region of light and heavy chain

      10. If a regular dose of drug or alcohol is not provided to an addicted person, he shows some withdrawal symptoms. List any four such withdrawal symptoms.
      Answer. The withdrawal symptoms are:
      a. Anxiety b. Shakiness c. Nausea d. Sweating

      11. Why is it that during changing weather, one is advised to avoid closed, crowded and air-conditioned places like cinema halls etc.?
      Answer. During changing weather, one is advised to avoid closed, crowded and air- conditioned placed like cinema halls, etc., because during this period the infectious agents are more humerous and prevalent to which we are more vulnerable.

      12. The harmful allele of sickle cell anemia has not been eliminated from human population. Such afflicted people derive some other benefits. Discuss.
      Answer. The harmful alleles get eliminated from population over a period of time, yet sickle cell anaemia is persisting in human population because SCA is a harmful condition which is also a potential saviour from malaria.
      Those with the benign sickle trait possess a resistance to malarial infection. The pathogen that causes the disease spends part of its cycle in the red blood cells and triggers an abnormal drop in oxygen levels in the cell. In carriers, this drop is sufficient to trigger the full sickle-cell reaction, which leads to infected cells being rapidly removed from circulation and strongly limiting the infection’s progress. These individuals have a great resistance to infection and have a greater chance of surviving outbreaks. This resistance to infection is the main reason the SCA allele and SCA disease still exist. It is found in greatest frequency in populations where malaria was and is still often a serious problem.

      13. Lymph nodes are secondary lymphoid organs. Explain the role of lymph nodes in our immune response.
      Answer. Lymph nodes are small solid structures located at different points along the lymphatic system. Lymph nodes trap the microorganisms or other antigens, which happen to get into the lymph and tissue fluid. Antigens trapped in the lymph nodes are responsible for the activation of lymphocytes present there and cause the immune response.

      14. Why is an antibody molecule represented as H2 L2 ?
      Answer. Each antibody molecule is made of the two heavy chains (H2 ) and two light chains (L2 ), hence represented as H2 L2 .

      15. What does the term ‘memory’ of the Immune system mean?
      Answer. When body encounters a pathogen for the first time produce a response called 1° response. 1° response is of low intensity. When body encounters the same pathogen subsequently then body elicits 2° response. 2° response is highly intensified. This is due to the fact that our body have memory of the first encounter.

      16. If a patient is advised Anti Retroviral Therapy, which infection is he suffering from? Name the causative organism.
      Answer. The patient is suffering from AIDS. The causative organism for AIDS is HIV (Human Immuno deficiency Virus).

      Short Answer Type Questions
      1. Differentiate between active immunity and passive immunity.
      Answer.

      2. Differentiate between benign tumor and malignant tumor.
      Answer.

      • Benign tumors normally remain confined to their original location and do not spread to other parts of the body and cause little damage.
      • Malignant tumors are a mass of proliferating cells called neoplastic or tumor cells. Neoplastic cells grow very rapidly, invading and damaging the surrounding normal tissues. As these cells actively divide and grow they also starve the normal cells by competing for vital nutrients.
      • Cells sloughed from such tumors reach distant sites through blood, and wherever they get lodged in the body, they start a new tumor there. This property called metastasis is the most feared property of malignant tumors.

      3. Do you consider passive smoking is more dangerous than active smoking? Why?
      Answer. Yes, passive smoking is also dangerous as the active smoking because the person is exposed to the same harmful effects of smoking like emphysema, bronchitis, lung cancer, urinary bladder cancer or even peptic ulcer.

      4. “Prevention is better than cure”. Comment.
      Answer. Prevention is better than cure is true as in same cases the disease is non- curable like AIDS and Hepatitis-B, and in some cases’ the treatment causes financial problems in the family.

      5. Explain any three preventive measures to control microbial infections.
      Answer. (i) Maintenance of personal and public hygiene is very important for
      prevention and control of many infectious diseases. Measures for personal hygiene include keeping the body clean consumption of clean drinking water, food, vegetables, fruits, etc. Public hygiene includes proper disposal of waste and excreta periodic cleaning and disinfection of water reservoirs, pools, cesspools and tanks and observing standard practices of hygiene in public catering.
      (ii) In cases of air-borne diseases such as pneumonia and common cold, in addition to the above measures, close contact with the infected persons or their belongings should be avoided.
      (iii) For diseases such as malaria and filariasis that are transmitted through insect vectors, the most important measure is to control or eliminate the vectors and their breeding places. This can be achieved by avoiding stagnation of water in and around residential areas, regular cleaning of household coolers, use of mosquito nets, introducing fishes like Gambusia in ponds that feed on mosquito larvae, spraying of insecticides in ditches, drainage areas and swamps, etc. In addition, doors and windows should be provided with wire mesh to prevent the entry of mosquitoes.

      6. In the given flow diagram, the*replication of retrovirus in a host is shown. Observe and answer the following questions.
      (a) Fill in (1) and (2).
      (b) Why is the virus called retrovirus?
      (c) Can the infected cell survive while viruses are being replicated and released?

      Answer. (a) 1. Viral DNA is produced by reverse transcriptase.
      2. New viral RNA is produced by infected cell.
      (b) HIV is called retrovirus because it forms DNA from RNA by reverse transcription.
      (c) Yes, infected cell can survive while viruses are being replicated and released.

      7. “Maintenance of personal and public hygiene is necessary for prevention and control of many infectious diseases”. Justify’ the statement giving suitable examples.
      Answer. Measures for personal hygiene include keeping the body clean consumption of clean drinking water, food, vegetables, fruits, etc. Public hygiene includes proper disposal of waste and excreta periodic cleaning and disinfection of water reservoirs, pools, cesspools and tanks, and observing standard practices of hygiene in public catering. These measures are particularly essential where the infectious agents are transmitted through food and water such as typhoid, amoebiasis and ascariasis.

      8. The following table shows certain diseases, their causative organisms and symptoms. Fill the gaps.

      Answer.

      9. The outline structure of a drug is given below.

      (a) Which group of drugs does this represent?
      (b) What are the modes of consumption of these drugs?
      (c) Name the organ of the body which is affected by consumption of these drugs.
      Answer. (a) Cannabinoids
      (b) Generally taken by inhalation and oral ingestion
      (c) Affect the cardiovascular system of the body

      10. Give the full form of CT and MRI. How are they different from each other? Where are they used?
      Answer. CT (computed tomography) and MRI (magnetic resonance imaging) are very useful to detect cancers of the internal organs. Computed tomography uses X-rays to generate a three-dimensional image of the internals of an object. MRI uses strong magnetic fields and non-ionising radiations to accurately detect pathological and physiological changes in the living tissue.

      11. Many secondary metabolites of plants have medicinal properties. It is their misuse that creates problems. Justify the statement with an example.
      Answer. Several plants, fruits and seeds having hallucinogenic properties and have been used for hundreds of years in folk-medicine, religious ceremonies and rituals all over the globe. When these are taken for a purpose other than medicinal use or in amounts/frequency that impairs one’s physical, physiological or psychological functions, it constitutes drug abuse.

      12. Why cannabinoids are banned in sports and games?
      Answer. As these days cannabinoids are being abused by some sports persons to increase their performance, that is why cannabinoids are banned in sports and games.

      13. What is secondary metabolism?
      Answer. Secondary metabolism is a term for pathways and small molecule products of metabolism that are not absolutely required for the survival of the organism. Examples of the products include antibiotics and pigments.

      14. Drugs and alcohol give short-term ‘high’ and long-term ‘damages’. Discuss.
      Answer. Curiosity, need for adventure and excitement, and experimentation, constitute
      common causes, which motivate youngsters towards drug and alcohol use.
      A child’s natural curiosity motivates him/her to experiment. This is complicated further by effects that might be perceived as benefits, of alcohol or drug use. Thus, the first use of drugs or alcohol may be out of curiosity or experimentation, but later the child starts using these to escape facing problems. Of late, stress, from pressures to excel in academics or examinations, has played a significant role in persuading the youngsters to try alcohol and drugs. The perception among youth that it is ‘cool’ or progressive to smoke, use drugs or alcohol, is also in a way a major cause for youth to start these habits. Television, movies, newspapers, internet also help to promote this perception. Other factors that have been seen to be associated with drug and alcohol abuse among adolescents are unstable or unsupportive family structures and peer pressure.

      15. Diseases like dysentery, cholera, typhoid etc., are more common in overcrowded human settlements. Why?
      Answer. Diseases like dysentery, cholera, typhoid etc., are more common in overcrowded human settlements because these are infectious diseases that can transmitted from one person to another. In overcrowded settlements there is more chances of transmission of disease from one person to other.

      16. From which plant cannabinoids are obtained? Name any two cannabinoids. Which part of the body is effected by consuming these substances?
      Answer. Cannabinoids are obtained from the inflorescence of the plant Cannabis sativa. Marijuana, hashish, charas, ganja are some of the cannabinoids. These chemicals interact with cannabinoid receptors of the body, mainly present in the brain. Cardiovascular system is affected adversely.

      17. In the metropolitan cities of India, many children are suffering from allergy/ asthma. What are the main causes of this problem? Give some symptoms of allergic reactions.
      Answer. Allergy is the exaggerated response of the immune system of certain antigens present in the environment. In metropolitan cities life style is responsible for lowering of immunity and sensitivity to allergens. More polluted environment increases the chances of allergy in children. Some symptoms of allergic reactions are sneezing, watery eyes, running nose and difficulty in breathing.

      18. What is the basic principle of vaccination? How do vaccines prevent microbial infections? Name the organism from which hepatitis B vaccine is produced.
      Answer. The principle of vaccination is based on the property of ’memory’ of the immune system. In vaccination, a preparation of antigenic proteins of pathogens or inactivated/live but weakened pathogens is introduced into the body. The antigens generate the primary immune response by producing antibodies. The vaccines also generate the memory B-cells and T-cells. When the vaccinated person is attacked by the same pathogens, the existing memory B-cells or T-cells recognise the antigen quickly and overwhelm the invaders with massive production of lymphocytes and antibodies. Hepatitis B vaccine is produced from yeast.

      19. What is cancer? How is a cancer cell different from the normal cell? How do normal cells attain cancerous nature?
      Answer. An abnormal and uncontrolled division of cells is termed as Cancer. The cancerous cells are different from the normal cells in the following ways.

      In our body, the growth and differentiation of cells is highly controlled and regulated. The normal cells show a property called contact inhibition.
      The surrounding cells inhibits uncontrolled growth and division of cells. The normal cells lose this property and become cancerous cells giving rise to masses of cells called tumors. Transformation of normal cells into cancerous cells is induced by some physical, chemical and biological agents (carcinogens).

      20. A person shows strong unusual hypersensitive reactions when exposed to certain substances present in the air. Identify the condition. Name the cells responsible for such reactions. What precaution should be taken to avoid such reactions?
      Answer. Allergy. Mast Cells are responsible for such reactions. To avoid such reactions following precautions must be taken:
      (i) The use of drugs like antihistamine, adrenalin and steroids quickly reduce the symptoms of allergy.
      (ii) Avoid contact with substances to which a person is hypersensitive.

      21. For an organ transplant, it is an advantage to have an identical twin. Why?
      Answer. Very often, when some human organs like heart, eye, liver, kidney fail to
      function satisfactorily, transplantation is the only remedy to enable the patient to live a normal life. Then a search begins—to find a suitable donor.
      Grafts from just any source—an animal, another primate, or any human beings cannot be made since the grafts would be rejected sooner or later. Tissue matching, blood group matching are essential before undertaking any graft/transplant and even after this the patient has to take immuno-suppresants all his/her life. The body is able to differentiate ‘self ’ and ‘nonself’ and the cell-mediated immune response is responsible for the graft rejection. In an identical twin there is no chance of rejection of transplanted organ, so it is advantageous.

      22. What are lifestyle diseases? How. are they caused? Name any two such diseases.
      Answer. Lifestyle diseases are defined as diseases linked with the way people live their life. This is commonly caused by alcohol, drug and smoking abuse as well as lack of physical activity and unhealthy eating. Diseases that impact on our lifestyle are heart disease, stroke and obesity.

      23. If there are two pathogenic viruses, one with DNA and other with RNA, which would mutate faster? And why?
      Answer. Both DNA and RNA are able to mutate. In fact, RNA being unstable, mutate at a faster rate. Consequently, viruses having RNA genome and having shorter life span mutate and evolve faster.

      Long Answer Type Questions
      1. Represent schematically the life cycle of a malarial parasite.
      Answer.

      2. Compare the life style of people living in the urban areas with those of rural areas and briefly describe how the life style affects their health.
      Answer. Urban areas
      The social environment: Urban environments are more likely to see higher rates of crime and violencfc. ‘
      The physical environment: In densely populated urban areas, there is often a lack of facilities and outdoor areas for exercise. In addition, air quality is often lower in urban environments which can contribute to chronic diseases such as asthma. In the developing world, urban dwellers often live in large slums which lack basic sanitation and utilities such as water and electricity. Access to health and social service: Persons of lower socioeconomic status are more likely to live in urban areas and are more likely to lack health insurance. The high prevalence of individuals without health insurance or citizenship creates a greater burden on available systems.
      Rural areas
      The social environment: Rural dwellers have significantly poorer health status than urban elders. Also, rural residents smoke more, exercise less, have less nutritional diets.
      The physical environment: Rural women especially less educated women, are more sedentary than urban women. While poor air quality and crime rates are likely to be less of an issue in rural areas, insufficiencies in the built environment make it difficult for rural residents to exercise and maintain healthy habits.
      Access to health and social seryice: Evidence indicates that rural residents have limited access to health care. Some rural areas have a higher proportion of uninsured and individually insured residents than urban areas.

      3. Why do some adolescents start taking drugs? How can this be avoided?
      Answer. The reasons why adolescents and youngsters take to consumption of drugs are:
      (i) Curiosity of child motivates him/her to experiment.
      (ii) Need for adventure and excitement.
      (iii) Peer group pressure
      (iv) Desire to do more physical and mental work.
      (v) To overcome frustration and depression, due to failure in examinations or in other activities.
      (vi) Unstable or unsupportive family structures.
      The following measures can be taken to avoid taking drugs:
      (i) Avoid undue pressure on child to perform beyond his/her capability in studies, sports ox any other activities.
      (ii) Education and counselling are very important to face problem of stress and failure in life.
      (iii) Seeking help from parents, elders and peers. This would help the young to share their feelings and concern.
      (iv) Looking for danger signs and taking appropriate measures to treat them.
      (v) Seeking professional and medical help for de-addiction and rehabilitation.

      4. In your locality, if a person is addicted to alcohol, what kind of behavioural changes do you observe in that person? Suggest measures to overcome the problem.
      Answer. The immediate adverse effects of drugs and alcohol abuse are manifested in the form of reckless behaviour, vandalism and violence. Excessive doses of drugs may lead to coma and death due to respiratory failure, heart failure or cerebral hemorrhage. A Combination of drugs or their intake along with alcohol generally results in overdosing and even deaths. The most common warning signs of drug and alcohol abuse among youth include drop in academic performance, unexplained absence from school/college, lack of interest in personal hygiene, withdrawal, isolation, depression,, fatigue, aggressive and rebellious behaviour, deteriorating relationships with family and friends, loss of interest in hobbies, change in sleeping and eating habits, fluctuations in w’eight, appetite, etc. There may even be some far-reaching implications of drug/alcohol abuse. If an abuser is unable to get money to buy drugs/alcohol he/she may turn to stealing. The adverse effects are just not restricted to the person who is using drugs or alcohol. At times, a drug/ alcohol addict becomes the cause of mental and financial distress to his/her entire family and friends.
      The age-old adage of‘prevention is better than cure’ holds true here also. It is also true that habits such as smoking, taking drug or alcohol are more likely to be taken up at a young age, more during adolescence. Hence, it is best to identify the situations that may push an adolescent towards use of drugs or alcohol, and to take remedial measures well in time. In this regard, the parents and the teachers have a special responsibility. Parenting that combines with high levels of nurturance and consistent discipline, has been associated with lowered risk of substance (alcohol/drugs/tobacco) abuse. Some of the measures mentioned here would be particularly useful for prevention and control of alcohol and drugs abuse among adolescents.

      5. What are the methods of cancer detection? Describe the common approaches for treatment of cancer.
      Answer. Cancer detection and diagnosis: Early detection of cancers, is essential as it allows the disease to be treated successfully in many cases. Cancer detection is based on biopsy and histopathological studies of the tissue and blood and bone marrow tests for increased cell counts in the case of leukemias. In biopsy, a piece of the suspected tissue cut into thin sections is stained and examined under microscope (histopathological studies) by a pathologist. Techniques like radiography (use of X-rays), CT (computed tomography) and MRI (magnetic resonance imaging) are very useful to detect cancers of the internal organs. Computed tomography uses X-rays to generate a three-dimensional image of the internals of an object. MRI uses strong magnetic fields and non-ionising radiations to accurately detect pathological and physiological changes in the living tissue.

      • Antibodies against cancer-specific antigens are also used for detection of certain cancers. Techniques of molecular biology can be applied to detect genes in individuals with inherited susceptibility to certain cancers. Identification of such genes, which predispose an individual to certain cancers, may be very helpful in prevention of cancers. Such individuals may be advised to avoid exposure to particular carcinogens to which they are susceptible (e.g., tobacco smoke in case of lung cancer).
      • Treatment of cancer: The common approaches for treatment of cancer are surgery, radiation therapy and immunotherapy. In radiotherapy, tumor cells are irradiated lethally, taking proper care of the normal tissues surrounding the-tumor mass. Several chemotherapeutic drugs are used to kill cancerous cells. Some of these are specific for particular tumors. Majority of drugs have side effects like hair loss anemia, etc. Most cancers are treated by combination of surgery, radiotherapy and chemotherapy. Tumor cells have been shown to avoid detection and destruction by immune system. Therefore, the patients are given substances called biological response modifiers such as a-interferon which activates their immune system and helps in destroying the tumor.

      6. Drugs like LSD, barbiturates, amphetamines, etc., are used as medicines to help patients with mental illness. However, excessive doses and abusive usage are harmful. Enumerate the major adverse effects of such drugs in humans.
      Answer. Drugs like barbiturates, amphetamines, benzodiazepines, and other similar drugs, that are normally used as medicines to help patients cope with mental illnesses like depression and insomnia, are often abused. Morphine is a very effective sedative and painkiller, and is very useful in patients who have undergone surgery. Several plants, fruits and seeds having hallucinogenic properties have been used for hundreds of years in folk-medicine, religious
      ceremonies and rituals all over the globe. When these are taken for a purpose other than medicinal use or in amounts/frequency that impairs one’s physical, physiological or psychological functions, it constitutes drug abuse. ,

      7. What is Pulse Polio-Programme of Government of India? What is OPV? Why is it that India is yet to eradicate Polio?
      Answer. Pulse Polio is an immunisation campaign established by the government of India to eliminate poliomyelitis (polio) in India by vaccinating all children under the age of five years against the polio virus. The project fights poliomyelitis through a large-scale pulse vaccination programme and monitoring for polio cases.

      • In 1995, following the Global Polio Eradication Initiative of the World Health Organization (1988), India launched Pulse Polio immunisation program with Universal Immunization Program which aimed at 100% coverage.
      • The last reported cases of wild polio in India were in West Bengal and Gujarat on 13 January 2011. On 27 March 2014, the World Health Organization (WHO) declared India a polio free country, since no cases of wild polio had been reported in for three years.
      • Polio vaccines are the vaccines used to prevent poliomyelitis (polio).One type uses inactivated poliovirus and is given by injection (IPV), while the other type uses weakened poliovirus and is given by mouth (OPV). The World Health Organization recommends all children be vaccinated against polio. The two vaccines have eliminated polio from most of the world. The oral polio vaccine was developed by Albert Sabin and came into commercial use in 1961. _

      8. What are recombinant DNA vaccines? Give two examples of such vaccines. Discuss their advantages.
      Answer. A recombinant vaccine is a vaccine produced through recombinant DNA technology. This involves inserting the DNA encoding an antigen that stimulates an immune response into bacterial or mammalian cells.
      Recombinant DNA technology has allowed the production of antigenic polypeptides of pathogen in bacteria or yeast. Vaccines produced using jthis approach allow large scale production and hence greater availability for immunisation, e.g., hepatitis B vaccine (Recombivax HB) produced from yeast. As of June 2015 one human DNA vaccine had been approved for human use, the single-dose Japanese encephalitis vaccine called IMOJEV, released in 2010 in Australia.
      Advantages of recombinant DNA vaccines:
      1. No risk for infection
      2. Ease of development and production
      3. Stability for storage and shipping
      4. Cost-effectiveness
      5. Expression and purification of recombinant proteins
      6. Long-term persistence of immunogen
      7. In vivo expression ensures protein more closely resembles normal eukaryotic structure, with accompanying post-translational modifications.


      Research Programs

      NIAID is composed of 7 research divisions: the Division of AIDS the Division of Allergy, Immunology, and Transplantation the Division of Clinical Research the Division of Extramural Activities the Division of Intramural Research the Division of Microbiology and Infectious Diseases and the Dale and Betty Bumpers Vaccine Research Center. NIAID scientists conduct intramural research in laboratories located in Bethesda, Rockville, and Frederick, Maryland, and in Hamilton, Montana. More information on NIAID programs, committees, and initiatives can be found on NIAID's web site at www.niaid.nih.gov.

      Division of AIDS

      The Division of AIDS (DAIDS) was formed in 1986 to develop and implement the national research agenda to address the HIV/AIDS epidemic. Toward that end, the Division supports a global research portfolio on HIV/AIDS, its related co-infections, and co-morbidities. With the ultimate goal of creating an “AIDS-free Generation,” the Division continually develops and supports the research infrastructure and scientific expertise needed to enable innovative approaches aimed at: 1) halting the spread of HIV through effective and acceptable prevention strategies and a preventive vaccine 2) treating and curing HIV infection 3) establishing treatment and prevention strategies for the HIV co-infections and co-morbidities of greatest significance and 4) partnering with scientific and community stakeholders to implement effective interventions. Carl W. Diffenbach, Ph.D. Director.

      Division of Allergy, Immunology, and Transplantation

      The mission of the Division of Allergy, Immunology, and Transplantation (DAIT) spans the acquisition of knowledge on the function of the immune system, and development of effective approaches for the diagnosis, treatment, and prevention of infectious and immune-mediated diseases, including asthma and allergic diseases, autoimmune disorders, primary immunodeficiency diseases, and rejection of transplanted organs, tissues, and cells. To achieve this goal, DAIT promotes and supports basic research to increase understanding of the development and function of the immune system, the mechanisms of protective immunity, and the causes and mechanisms that lead to the development of immunologic diseases. DAIT’s clinical research activities apply this knowledge to the development and evaluation of new tolerogenic and immunomodulatory approaches for the diagnosis, treatment and prevention of immune-mediated diseases and transplant rejection. Daniel Rotrosen, M.D., Director.

      Division of Clinical Research

      The Division of Clinical Research (DCR) plays an integral role in facilitating the efficient and effective performance of NIAID research programs on both the domestic and the international level. This is accomplished through a multi-faceted approach to the provision and support of services vital to the research infrastructure that include oversight and management of intramural clinical research, program planning and management, regulatory monitoring and compliance, statistical consultation and research methodology, and clinical research capacity building. H. Clifford Lane, M.D., Director.

      Division of Extramural Activities

      The Division of Extramural Activities (DEA) serves NIAID's extramural research community and the Institute in several key areas: overseeing policy and management for grants and contracts managing NIAID's research training, small business, and international programs and conducting initial peer review for funding mechanisms with Institute-specific needs. In addition to providing broad policy guidance to Institute management, DEA also oversees all of NIAID's chartered committees, including the National Advisory Allergy and Infectious Diseases Council disseminates information to its extramural community through its large Internet site and develops extramural staff training and communications through the NIAID intranet. Matthew Fenton, Ph.D., Director.

      Division of Intramural Research

      The Division of Intramural Research (DIR) is composed of 21 laboratories and 3 branches that conduct biomedical research programs covering a wide range of disciplines relating to immunology, allergy, and infectious diseases. This includes the subdisciplines of virology, microbiology, biochemistry, parasitology, epidemiology, mycology, molecular biology, immunology, immunopathology, and immunogenetics. In addition, DIR supports a large clinical effort to conduct patient-centered research in allergy, immunology, and infectious diseases. Steven M. Holland, M.D.​, Director.

      Division of Microbiology and Infectious Diseases

      The Division of Microbiology and Infectious Diseases (DMID) supports extramural research to control and prevent diseases caused by virtually all human infectious agents except HIV. DMID’s portfolio includes a wide variety of projects on bacterial, viral, parasitic, and prion diseases. DMID-supported research spans the spectrum from basic biology of human pathogens and their interaction with human hosts, through translational and clinical research toward the development of new and improved diagnostics, drugs, and vaccines for infectious diseases. DMID supports basic research on organisms on the NIAID Category A to C list of priority pathogens for biodefense and emerging and re-emerging infectious diseases, as well as translational and clinical research to develop medical countermeasures for diseases caused by these agents. Emily Erbelding, M.D., M.P.H.​, Director.

      Dale and Betty Bumpers Vaccine Research Center

      While the core research focus of the VRC remains the development of an effective vaccine for prevention of HIV-1/AIDS, VRC capabilities informed by its work on HIV have led to significant contributions to vaccine development for other high-burden diseases such as influenza, RSV and malaria, as well as for biodefense threats and emerging infectious diseases including Ebola, Chikungunya, alphavirus encephalitides, SARS, and MERS. The VRC’s programmatic framework encompasses basic bench research, antigen discovery, comprehensive immune assessment, vaccine production capability, and conduct of clinical trials. The technology advances of the VRC in numerous areas, including antigen discovery, vaccine vector development, modulation and measurement of immunity, adjuvant use, manufacturing optimization, pre-clinical testing, efficient regulatory and clinical evaluation, and analysis of human immune responses, all have translated into opportunities for associated advances in immune modulator discovery, development, and implementation for other diseases.


      Human Biology Appears to Have Two Seasons, Not Four: Study

      The human body apparently disagrees with Mother Nature on how many seasons there are.

      Instead of four seasons, human biology appears to have two, according to a team of Stanford University researchers.

      "We're taught that the four seasons -- winter, spring, summer and fall -- are broken into roughly equal parts throughout the year, and I thought, 'Well, who says?' " said Michael Snyder, a professor and chair of genetics. "It didn't seem likely that human biology adheres to those rules."

      So he and his colleagues conducted a study guided by people's molecular compositions to let the biology reveal how many seasons there are.

      They analyzed four years of molecular data from 105 people, aged 25 to 75. About four times a year, participants provided blood samples that were analyzed for molecular information about immunity, inflammation, heart health, metabolism, the microbiome and more. Participants' diet and exercise habits were also tracked.

      Overall, the study found that more than 1,000 molecules ebb and flow during the year, especially during late spring-early summer and late fall-early winter.

      For example, late spring coincided with a rise in inflammatory biomarkers known to play a role in allergies, a spike in molecules involved in rheumatoid arthritis and osteoarthritis, a peak in HbAc1, a protein that signals risk for type 2 diabetes, and the highest annual levels of the gene PER1, an important regulator of the sleep-wake cycle.

      In early winter, there were increases in immune molecules that help fight viral infections molecules involved in acne development and markers of high blood pressure.

      The researchers also found differences between people who were insulin-resistant (their bodies don't process glucose normally) and those who weren't.

      Insulin-resistant people had higher levels of Veillonella, a type of bacteria involved in lactic acid fermentation and the processing of glucose, throughout the year, except during mid-March through late June, according to findings published Oct. 1 in the journal Nature Communications.

      Snyder noted that the study involved people in California, and it's likely that the molecular patterns of people in other regions would differ.

      Understanding such seasonal changes in human biology could help guide health care and the design of clinical drug trials, he suggested.


      Copyright © 2020 HealthDay. All rights reserved.


      Background

      Individuals due to be vaccinated may have had previous allergies, and may ask their healthcare professional for advice on their suitability for vaccination.

      • those with allergies, including anaphylaxis, to a food, insect sting or most medicines (where the trigger has been identified), can proceed with vaccination as normal according to local guidelines, as long as they are not known to be allergic to any component (excipient) of the vaccine
      • anyone with a family history of allergies, a previous non-systemic reaction to a vaccine, hypersensitivity to non-steroidal anti-inflammatory drugs (e.g. aspirin, ibuprofen) or mastocytosis can proceed with vaccination as normal, according to local guidelines.

      Allergic to Penicillin? You May Not Be

      Nineteen out of 20 people who have been told they are allergic to penicillin are not truly allergic to the drug.

      Millions of Americans who believe they are allergic to penicillin are not actually allergic. But they are steered away from using some of the safest, most effective antibiotics, relying instead on substitutes that are often pricier, less effective, and more likely to cause complications such as antibiotic-resistant infections.

      Those are the conclusions of a new paper on penicillin allergy. Experts in allergy and infectious disease, including the paper’s authors, are now urging patients to ask doctors to review their medical history, and re-evaluate whether they have a true penicillin allergy.

      The evaluation, which may require allergy skin testing and ideally should be done while people are healthy, is especially important for pregnant women, people with cancer and those in long-term care, and anyone anticipating surgery or being treated for a sexually transmitted infection.

      “When you have a true infection that needs to be treated, the physician will see you have the allergy and not question it,” said Dr. Erica S. Shenoy, lead author of the new report, published earlier this month in JAMA. “What we are trying to do is get people to question it.”

      Though an allergy can develop at any age, penicillin allergies are often first recorded in childhood, when penicillin is the No. 1 antibiotic prescribed, she said. If a child on penicillin develops a rash or other symptom and it is erroneously attributed to the drug, the allergy label sticks, often for life.

      “From then on it’s on the chart,” said Dr. Shenoy, associate chief of infection control at Massachusetts General Hospital.

      The review was carried out with input from the boards of three professional medical organizations: the American Academy of Allergy, Asthma and Immunology the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America. All three groups endorsed the findings.

      There is no question some people have potentially life-threatening allergic reactions to penicillin, but the label appears to have been applied far too broadly, experts say. About 10 percent of Americans report having a penicillin allergy, and the rate is even higher among older people and hospital patients, 15 percent of whom have a documented penicillin allergy.

      But studies that have gone back and conducted allergy skin testing on patients whose medical records list a penicillin allergy have found that the overwhelming majority test negative. A 2017 review of two dozen studies of hospitalized patients found that over all, 95 percent tested negative for penicillin-specific immunoglobulin E, or IgE, antibodies, a sign of true allergy.

      “We used to say nine out of 10 people who report a penicillin allergy are skin-test negative. Now it looks more like 19 out of 20,” said Dr. David Lang, president-elect of the American Academy of Allergy, Asthma and Immunology and chairman of allergy and immunology in the respiratory institute at the Cleveland Clinic.

      Patients can get mislabeled as allergic to penicillin in a number of different ways. They may experience bad drug reactions like headaches, nausea or diarrhea, which are not true allergic reactions but are misinterpreted. Alternatively, they may develop a symptom like a rash, which is indicative of a real allergic reaction but could be caused by an underlying illness and not by the drug.

      And many people who have avoided penicillin for a decade or more after a true, severe allergic reaction will not experience that reaction again. “Even for those with true allergy, it can wane,” said Dr. Kimberly Blumenthal, the review’s senior author, who is an allergist and an assistant professor at Harvard Medical School. “We don’t really understand this, but once you’ve proven you’re tolerant, you go back to having the same risk as someone who never had an allergy” to penicillin.

      It’s a good idea to find out if your allergy is real or not because penicillin antibiotics, which are part of a group of drugs called beta-lactam antibiotics, are among the safest and most effective treatments for many infections. Beta-lactams are the treatment of choice for Group A Streptococcus, which can cause pneumonia, toxic shock and other syndromes Group B Strep, which causes meningitis Staphylococcus aureus and other pathogens. Beta-lactams are used prophylactically to prevent infections during surgery, and studies have found that patients with penicillin allergies who are given second-line antibiotics before surgery had a substantially greater risk of a surgical site infection. Beta-lactams are also the first line treatment for syphilis and gonorrhea.

      Substitutes like fluoroquinolones, clindamycin, vancomycin and third-generation cephalosporins are available, but they are often both less effective and more expensive, and many are broader spectrum antibiotics, which can lead to the development of resistant organisms and other side effects, experts say. Studies have shown that patients with penicillin allergies are at increased risk for developing serious infections like Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant enterococcus.

      Don’t challenge yourself to penicillin on your own, experts warn. Patients who have been told they’re allergic to penicillin should talk to their doctors, who should take a careful history and review the symptoms of the reaction.

      If the past reaction to penicillin included symptoms like headache, nausea, vomiting and itching, or the diagnosis was made based on a family history of the allergy, the patient is considered low risk and may be able to take a first dose of penicillin or a related antibiotic, such as amoxicillin, under medical observation.

      If the past reaction included hives, a rash, swelling or shortness of breath, patients should have penicillin skin testing, which involves a skin prick test using a small amount of penicillin reagent, followed by a second test that places the reagent under the skin if the first test is negative. If both tests are negative, the patient is unlikely to be allergic to penicillin, and an oral dose may be given under observation to confirm.


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      Science

      Vol 318, Issue 5851
      02 November 2007

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      By Lars Råberg , Derek Sim , Andrew F. Read

      Science 02 Nov 2007 : 812-814

      In addition to developing resistance to parasite infection, mice can evolve to tolerate malarial parasites by limiting the damage caused by their presence.