Hypersensitivity Disorders Flashcards
Type I
Anaphylaxis = bee sting, food/drug allergies
Allergic and atopic disorders = rhinitis, hay fever, eczema, hives, asthma
Type I presentation
Immediate, anaphylactic, atopic
Free Ag cross-links IgE on mast cells and basophils and leads to immediate release of vasoactive amines that act on postcapillary venules
Type II
Autoimmune hemolytic anemia Pernicious anemia Idiopathic thrombocytopenic purpura Erythroblastosis fetalis Acute hemolytic transfusion reactions Rheumatic fever Goodpasture syndrome Bullous pemphigoid Pemphigus vulgaris
Type II presentation
Disease tends to be specific to tissue or site where antigen is found
Cytotoxic
IgM and IgG bind to fixed antigen on enemy cell, leading to cellular destruction via opsonization, complement-mediated lysis, or AB-dependent cell-mediated cytotoxicity
Type III
SLE Polyarteritis nodosa Poststreptococcal glomerulonephritis Serum sickness Arthus reaction (swelling and inflammation following tetanus vaccine
Type III presentation
Can be associated with vasculitis and systemic manifestations
Type IV
Multiple sclerosis Guillain-Barre syndrome Graft-versus-host disease PPD (test for M. tuberculosis) Contact dermatitis (poison ivy, nickel allergy)
Type IV presentation
Response is delayed and does NOT involve ABs (vs. types I, II, and III)
Delayed (T-cell-mediated)
Sensitized T cells encounter Ag and release lymphokines which leads to macrophage activation
Types I-IV “ACID”
Anaphylactic and Atopic = type I
Cytotoxic (AB mediated) = type II
Immune complex = type III
Delayed (cell mediated) = type IV
Anaphylaxis (bee sting, food/drug allergy)
Type I
Autoimmune hemolytic anemia
Type II
SLE
Type III
Multiple sclerosis
Type IV
Allergic and atopic disorders (rhinitis, hay fever, eczema, hives, asthma)
Type I
Pernicious anemia
Type II
