Therapeutic effect of cyclosporine A in thrombocytopenia after myeloablative chemotherapy in acute myeloid leukaemia.

Four patients with acute myelogenous leukaemia (AML), who developed isolated thrombocytopenia after anti-leukaemic chemotherapy, were treated with cyclosporine A and showed significantly enhanced platelet recovery. All four patients demonstrated decreased bone marrow megakaryocytes without dysplastic features, absence of identifiable peripheral autoimmune platelet destruction or cytogenetic evidence of secondary myelodysplasia. The duration of response to cyclosporine A ranged from 6 days to 40 months. The mechanism of cyclosporine A-induced platelet recovery may include inhibition of negative modulators and induction of thrombopoietic cytokines mediated by bone marrow regulatory cells.