All are given to prevent rejection in organ transplantation except:

Ans: a (Hyperimmune sera) Ref: Davidson, 20th ed, p. 90IMMUNOSUPPRESSIVE DRUGS USED IN TRANSPLANTATIONDrugAnti-proliferativeagentse.g. Azathioprine,Mycophenolate mofetilMechanism of actionInhibit DNA synthesis: block lymphocyte proliferation and cytokine synthesisMay be directly cytotoxic at high dosesMajor adverse effectsIncreased susceptibility to infectionLeucopeniaHepatotoxicityCalcineurin inhibitors e.g. cyclosporin, tacrolimusInhibit T-cell signaling: prevents lymphocyte activation and blocks cytokine transcriptionIncreased susceptibility to infectionHypertensionNephrotoxicityDiabetogenic(especially tacrolimus)Gingival hypertrophy, hirsutism (cyclosporin)CorticosteroidsDecrease phagocytosis and release of proteolytic enzymes; decrease lymphocyte activation and proliferation; decrease cytokine production; decrease antibody productionIncreased susceptibilityto infectionOther complicationsAnti-T-cell induction agents anti-thymocyte globulin (ATG), anti-CD3 monoclonal antibodyDepletion or blockade of T cells by antibodies to cell surface proteinsProfound non-specific immunosuppressionIncreased susceptibility to infectionInvestigations to avoid rejectionHLA typingHLA typing using genetic or serological assays determines an individual's HLA polymorphisms, and facilitates donor-recipient matching.Anti-HLA antibody screeningPotential transplant recipients are screened for the presence of anti-HLA antibodies using either recombinant HLA proteins or a pool of lymphocytes from individuals with broadly representative HLA types. If antibodies are detected, their specificity is further characterised and the recipient is excluded from receiving a transplant which carries these alleles.Donor-recipient cross-matchingCross-matching is a functional assay that directly tests whether serum from a recipient (which potentially contains anti-donor antibodies) is able to bind and/or kill donor lymphocytes. It is specific to a prospective donor, and is done immediately prior to transplantation. A positive cross-match is a contraindication to transplantation because of the risk of hyperacute rejection.C4d stainingC4d is a fragment of the complement protein C4, and deposition of C4d in graft capillaries indicates local activation of the classical complement pathway. This is specific to antibody-mediated damage and is useful in the early diagnosis of vascular rejection.