Hypersensitivity and its types.pptx

A brief description over Hypersensitivity and its types.

1. SARDAR PATEL MAHAVIDYALAYA CHANDRAPUR DEPARTMENT OF MICROBIOLOGY 2021-2022 Hypersensitivity and its types A Seminar on PRESENTED BY DEEPAK CHAWHAN (M.Sc. II Yr. Semester- IV)

2. CONTENTS Introduction Classification of Hypersensitivity Type I Hypersensitivity- Causes, Signs of Hypersensitivity, Diagnosis and Treatment Type II Hypersensitivity- Example, Diagnosis and Treatment Type III Hypersensitivity- Example, Diagnosis and Treatment Type IV Hypersensitivity- Example, Diagnosis and Treatment References

3. INTRODUCTION Hypersensitivity (also called as Hypersensitivity reaction or intolerance). It refers to excessive, undesirable, damaging, discomfort- producing and sometimes fatal reactions produced by the normal immune system, including allergies and autoimmunity. Hypersensitivity reactions require pre-sensitized (immune) state of the host.

4. Classification of Hypersensitivity Type I (Immediate/Atopic/Anaphylactic) Type II ( Cytotoxic Hypersensitivity/ Antibody Mediated Hypersensitivity) Type III (Immune Complex/ Arthus Hypersensitivity) Type IV (Cell Mediated/ Delayed Type of Hypersensitivity)

5. Type I Hypersensitivity Type I Hypersensitivity also known as Immediate/Atopic/Anaphylactic Hypersensitivity. This develops within few minutes of exposure to the allergen. The reaction is mediated by Immunoglobulin E and other factors involved in inflammation. The primary cellular component in this hypersensitivity is the mast cell or basophils .

6. Causes - The allergens are considered to be the cause of hypersensitivity. The allergens are the non-parasite antigens that stimulate the type I hypersensitivity response.

7. Signs of Type I Hypersensitivity The reaction may involve skin ( urticaria and eczeema ), eyes (conjunctivitis), nasopharynx ( rhinorrhea , rhinitis), bronchopulmonary tissues ( asthama ) and gastroinestinal tract (Gastroenteritis). The reaction may cause a range of symptoms from minor inconvenience to death.

8. Diagnosis of Type I Hypersensitivity Diagnostic tests for immediate hypersensitivity include skin (prick and intradermal ) tests, measurement of total IgE and specific IgE antibodies against the suspected allergens. Total IgE and specific IgE antibodies are measured by a modification of enzyme immunoassay (ELISA). Increased IgE levels are indicative of an atopic condition, although IgE may be elevated in some non-atopic diseases (e.g., myelomas, helminthic infection, etc).

9. Treatment of Type I Hypersensitivity Drugs- > Non-steroidal anti- inflammatories (NSAIDs) > Antihistamines block histamine receptors. > Steroids> Theophylline OR epinephrine -prolongs or increases CAMP levels in mast cells which inhibits degranulation . Immunotherapy- > Desensitization ( hyposensitization )also known as allergy shots. > Repeated injections of allergen to reduce the IgE on Mast cells.

10. Type II Hypersensitivity Type II Hypersensitivity also known as Cytotoxic Hypersensitivity/ Antibody Mediated Hypersensitivity. This may affect a variety of organs and tissues. This develops within minutes to hours of exposure to the allergen. The reaction is mediated by antibodies of Immunoglobulin M or Immunoglobulin G Class and complements.

11. Hemolytic disease in Newborn -

12. Diagnosis of Type II Hypersensitivity Diagnostic tests for detection of circulating antibodies against the tissues involved by immunofluoresence . Stainning procedures also used in the diagnosis.

13. Treatment of Type II Hypersensitivity Drugs- > Non-steroidal anti- inflammatories (NSAIDs) > Immunosuppresive Agents.

14. Type III Hypersensitivity Type III Hypersensitivity also known as Antigen- Antibody Immune Complex/ Arthus Hypersensitivity. This may affect capillaries, joints and trigger inflammation. The reaction may be general (e.g., serum sickness) or may involve individual organs including skin (e.g., systemic lupus erythematosus , Arthus reaction), kidneys (e.g., lupus nephritis), lungs(e.g., aspergillosis ), joints (e.g., rheumatoid arthritis) or other organs. This develops within 3 - 10 hours after exposure to the antigen. The reaction is mediated by immune complexes mostly of Immunoglobulin G, although Immunoglobulin M Class may also be involved.

15. Signs of Type III Hypersensitivity -

16. Diagnosis of Type III Hypersensitivity Diagnosis involves examination of tissue biopsies for the deposit of Immunoglobulins and complement by immunofluoresence microscopy. The presence of immune complexes in the serum and depletion in the level of complement are also diagnostic.

17. Treatment of Type III Hypersensitivity Drugs- > Non-steroidal anti- inflammatories (NSAIDs)

18. Type IV Hypersensitivity Type IV Hypersensitivity also known as Cell Mediated/ Delayed Type of Hypersensitivity. This reaction peaks within 48 hours after the injection of antigen. There are two different types of reactions capable of causing tissue injury in this way. 1.delayed type hypersensitivity is mediated by CD4+ helper Tcells 2. cell mediated cytotoxicity , is mediated by CD8+ T cells.

19. Signs of Type IV Hypersensitivity -

20. Diagnosis of Type IV Hypersensitivity Diagnostic test involves Montoux test Patch test (for contact dermatitis) Mitogenic response Interleukin- 2 production

21. Treatment of Type IV Hypersensitivity Drugs- > Corticosteroids > Other Immunosuppresive agents

22. References Immunology and Medical Microbiology, R.P. Singh Textbook of Microbiology& Immunology, 2 nd Edition, Subhash chandra Parija

23. Thank you…..