click below
click below
Normal Size Small Size show me how
Imm:Hypersensitivity
Hypersensitivity Reactions
| Question | Answer |
|---|---|
| Anaphylaxis | Type I |
| Allergic rhinitis (hay fever) | Type I |
| Asthma | Type I |
| Eczema | Type I |
| IgE mediated: free Ag cross-links IgE on presensitized mast cells and basophils --> trigger release of vasoactive amines | Type I |
| Ab mediated: IgM, IgG bind fixed Ag on cell--> lysis by complement or phagocytosis | Type II |
| Immune complex mediated: Ag-Ab complex activates complement --> attract neutrophils --> neutrophils release lysosomal enzymes | Type III |
| Delayed (T-cell) mediated: sensitized T lymphocytes encounter Ag --> release lymphokines --> macrophage activation | Type IV |
| Contact dermatitis | Type IV |
| Allergic rhinitis & anaphylaxis | Type I |
| Hemolytic anemia | Type II |
| Idiopathic thrombocytopenic purpura | Type II |
| Erythroblastosis fetalis | Type II |
| Rheumatic fever | Type II |
| Goodpasture's syndrome | Type II |
| Bullous pemphigoid | Type II |
| Graves' disease | Type II |
| Myasthenia gravis | Type II |
| SLE | Type III (immune complex) |
| Rheumatoid arthritis | Type III (immune complex) |
| Polyarteritis nodosum | Type III |
| Post-strep glomerulonephritis | Type III |
| Serum sickness | Type III (immune complex) |
| Arthus reaction | Type III |
| Hypersensitivity pneumonitis | Type III (immune complex) |
| Type I diabetes mellitus | Type IV |
| Multiple sclerosis | Type IV |
| Guillain-Barre syndrome | Type IV |
| Hashimoto thyroiditis | Type IV |
| Graft vs host disease | Type IV |
| PPD (TB test) | Type IV |
| Contact dermatitis | Type IV |
| Type II (Ab-mediated) | IgM, IgG bind to Ag on "enemy" cell-->lysis or phagocytosis |
| Type III (immune complex) | Ag-Ab complexes activate complement which attract PMNs who release dangerous substances |
| Type IV (delayed) | Sensitized T cells encounter Ag and release lymphokines to activate macrophages |
| Type III (serum sickness) | Fever, urticaria, arthralgias, proteinuria, lymphadenopathy 5-10 days after Ag exposure |