Hypersensitivity (also called hypersensitivity reaction or intolerance) refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity.

1. Yash Gupta
I.E.T Bundelkhand University
Jhansi

2. •Hyperactive or excessive immune response to foreign
antigens
•Primarily mediated by the cells of adaptive immune
response i.e.T-cells and B-cells
•Damage occurs by the same mechanism as in normal
pathogen killing

3. • The term “Hypersensitivity” was firstly used by Emil
von Behring in 1893 while testing for diphtheria
toxins.
• The term “Allergy” was coined by Clemens von
Pirque in1906.
• Taken from the Greek word allos ergos meaning
“alteredreactions”.
Emil vonBehring
Clemens vonPirque

4. Source:Owen,J.A.,Punt,J.,Stanford S.A.,Kuby Immunology 7th Edition,W. H. Freeman andCompany, NewYork

5. Sensitization Elicitation Reactions

6. Source:Owen,J.A.,Punt,J.,Stanford S.A.,Kuby Immunology 7th Edition,W. H. Freeman andCompany, NewYork

7. Exposure Syndrome Symptoms
Respiratory mucosa Allergic rhinitis Nasal Pruritis,rhinorrhea,
congestion
Asthma Bronchospasm, chronicairway,
inflammation
Gastrointestinal
mucosa
Food allergy Cramping, colic vomit,diarrhea,
eczema
Skin Contact utricularia Hives pruritis
Circulation Anaphylaxis Hives, laryngeal edema,hypotension

8. Ab function Target Result Syndrome
Opsonization Platelets Splenic clearance Drug-induced
decreasedplatelets
and bleeding
Complement
Fixation
Erythrocytes RBC destruction Intravascul
ar
hemolytic
anemia
Antibody dependent
cellular
Cytotoxicity (ADCC)
Cardiac myosin,
perivascular
connectivetissue
Endocarditis,
myocarditis
Rheumatic heart
disease
Neutralization Acetylcholine
receptor
Muscle weakness Myasthenia
gravis
This type involve antibody-mediated cells destruction by immunoglobulins of heavy chain classes other than IgE
Antibody bound to a cell-surface antigen can induce death of the antibody-boundcellby distinct mechanisms

9. Source:Owen,J.A.,Punt,J.,Stanford S.A.,Kuby Immunology 7th Edition,W. H. Freeman andCompany, NewYork

10. Ag-Ab complexes deposit in local blood vessel walls
• Fix complement & generateC5a
Chemoattractant forneutrophils
Mast cellactivatorand histamine release hives, tissue edema
Bind Fc receptors on neutrophils cause release ofO2 free radicals,proteases
Serum sickness

11. Source:Brooks,G.F.,Jawetz,E.,Melnick,J.L.,&Adelberg,E.A. (2010).Jawetz,Melnick,&Adelberg’smedicalmicrobiology.NewYork:McGraw HillMedical.

13. Source:Owen,J.A.,Punt,J.,Stanford S.A.,Kuby Immunology 7th Edition,W. H.Freeman andCompany, NewYork

14. Type Site ClinicalAppearance Antigen
Contact dermatitis Epidermis Erythematous popular
scaling,blistering
Poison ivy, latex,organic
molecules, metals(Ni2+)
Tuberculin test Dermis Local induration(swelling) Mycobacterium candida
Drug rash Circulation Measles like rash,LFT’s Almostany
medication