All of the following immunosuppressives cause profound myelosuppression except:: (A) Sirolimus, (B) Cyclosporine, (C) Azathioprine, (D) Mercaptopurine
Answer is B. Ciclosporin&;s main effect is to lower the activity of T-cells; it does so by calcineurin-phosphatase pathway.Unlike cytotoxic immunosuppressants, it is free of toxic effects on bone marrow and RE system as it doesn&;t act on cell cycle.(ref: KD Tripathi 6/e p839)