COMSAE PRACTICE Questions With Solutions

COMSAE PRACTICE Questions With Solutions CD4 AND CD8 T LYMPHOCYTES ARE NORMALLY FOUND IN thymic medulla? Hypersensitivity: 4 types anaphylactic and atopic (type I); cytotoxic (ab mediated type II); Immune complex (type III) Delayed (cell mediated, type IV) ACID!!! TYPE I HSR I=IgE Anaphylactic and atopic --free ag cross link IgE!!! on presensitized mast cells and basophils>> vasoactive amines that act at post capillary venues (like histamine); rapid develop after antigen exposure bc of preformed antibody; delayed phase results from mast cells and basophils releasing cytokines that induce cellular inflamm Type I = first and fast Type I II and III are all antibody mediated Test: skin test or blood test (ELISA) for allergen specific IgE; Ex: anaphylaxis (food, drug, or bee sting) Interpretation of Type I Allergen binds specific allergen IgE's on Mast cells and basophis>>leading to degranulation "" (vasoactive amines that act @ post cap venules) COMSAE PRACTICE Questions With Solutions Type II HSR Antibodies bind to cell -surface Ags>> cell destruction, inflammation, and cellular dysfunction Cell destruction cell is opsonized (coated) by Abs, leading to either: 1. phagocytosis and/or activation of complement system 2. NK cell killing (ab dependent cellular cytotoxicity) **complement or cytotoxicity!!** Inflammation --bind of abs to cell surfaces>>active of complement system and Fc receptormediated inflammation; Cell dysfunction: abs bind to cell surface receptors> abnormal blockade or active of downstream process Direct Coombs Test For type II HSR direct Coombs detects abs attached directly to the RBC surface Indirect Coombs test --detect presence of unbound antibodies in the serum Examples type II HSR Cellular destruction autoimmune -hemolytic anemia