Cyclosporine-related encephalopathy following allogeneic bone marrow transplantation.

A 46-year-old man with chronic myelogenous leukemia received allogeneic bone marrow transplantation (BMT) from a partially human leukocyte antigen (HLA)-mismatched sibling. Cyclosporine (CYA)-related encephalopathy developed on days 10 and 21 following BMT, and CYA-related thrombotic thrombocytopenic purpura (TTP) developed on day 45 following BMT. We measured serum concentrations of thrombomodulin (TM) as a marker of endothelial injury. The concentrations of TM were increased during the encephalopathy or TTP and decreased following recovery. Since CYA can cause endothelial injury, we suggest that CYA-induced endothelial injury is common to the pathogenesis of both the encephalopathy and the TTP. CYA therapy should be reinstituted with extreme caution in patients with a past history of CYA-related encephalopathy, since readministration of a low-dose CYA can evoke the immediate return of the encephalopathy.