| immunosuppression | <immunology> This occurs when T and/or B clones of lymphocytes are depleted in size or suppressed in their reactivity, expansion or differentiation. It may arise from activation of specific or non-specific T suppressor lymphocytes of either T or B clones or by drugs that have generalised effects on most or all T or B lymphocytes. Cyclosporin A and FK506 act on T-cells, as does antilymphocyte serum, alkylating agents such as cyclophosphamide are less specific in their action and damage DNA replication, while base analogues interfering with guanine metabolism act in a similar way. See: immunophilin. (18 Nov 1997) |
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