<prompt> All of the following immunosuppressives cause profound myelosuppression except:SirolimusCyclosporineAzathioprineMercaptopurine  <response>: 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 6e p839 