A patient was on treatment with penicillin. He developed pallor but there was no shortness of breath, urticaria or wheezing. On investigation, antibodies against penicillin were found in his blood. What is the type of hypersensitivity reaction that most likely occurred in this patient?
Correct Answer: Type II hypersensitivity
Description: Ans. b. Type II hypersensitivity (Ref: Robbins 9 c p205.8/e p653, 202)Penicillin hypersensitivity reaction is an example of type II, antibody mediated hypersensitivity reaction.Examples of type II hypersensitivity* Auto immune hemolytic anemia* Autoimmune thrombocytopenic purpura* Pemphigus vulgaris* ANCA mediated vasculitis* Goodpasture syndrome* Myasthenia gravis* Acute rheumatic fever* Graves disease* Insulin resistant diabetes* Pernicious anemia Mechanisms of drug-induced immunohemolytic anemiaAntigenic drugs(Hapten Model)Tolerance-breaking drugs(Auto antibody Model)* Hemolysis usually follows large, intravenous doses of the offending drugQ* Occurs 1 to 2 weeks after therapy is initiatedExamples:* Penicillin and cephalosporins, bind to the red cell membrane and are recognized by anti-drug, as in penicillin-induced hemolysisQ* Quinidine-induced hemolysisQ, the antibodies recognize a complex of the drug and a membrane protein.* These drugs, of which the antihypertensive agent alpha- methyldopa is the prototype, induce the production of antibodies against red cell antigens, particularly the Rh blood group antigensQ. Types of HypersensitivityType 1 (lgE)QType II(IgG and lgM)Q Cytotoxic, complement mediated lysisQType IIIImmune complex (IgM and IgG)Type IVDelayed hypersensitivity (Cellular immunity)Includes:* Local: Eczema, Hay fever. Asthma (Atopy)Q* Systemic: AnaphylaxisExamples:* Theoblad Smith phenomenon:Q This is anaphylaxis in guinea pigs.* PK reaction (Prusnitz Kunster):Q Demonstrate that IgE is homocytotropic i.e. species specific.* Casoni's test: Immediate type (IgE) HypersensitivityIncludes:* Complement mediated lysis* Antibody dependent cell mediated toxicity (formerly classified as type l)Q* Changes in cellular function (former type V)Q* Increased function: Grave's diseaseQ * Decreased function: M. GravisQ* PhagocytosisExamples:- Those with Ag on RBC:- Blood transfusion reactionQ- Hemolytic anemia e.g. with I.M. and mycoplasmaQ* Those with Ag on Neutrophils: AgranulocytosisQ* Those with Ag on platelets: ITPdeg* Those with Ag on basement membrane: Goodpasture'sQ syndrome* Pemphigus vulgaris* ANCA mediated vasculitis* Acute rheumatic fever* Insulin resistant diabetes* Pernicious anemiaIncludes:* Local: Arthus reactionQ* Systemic: Serum sicknessQExamples:* Shick's testQ* Post streptococcal G.N.Q* Detected by RAJI AssayQIncludes:* Tuberculin testQ* Lepromin textQ* Contact dermatitis* Jones-mote reaction (cutaneous basophilic hypersensitivity)Q* Graft rejection (chronic)Q
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