[Thrombotic microangiopathy following stem cell transplantation]

Stem cell transplantation associated microangiopathy (TA-TMA) occurs in about 7% of all transplantations. While it resembles in all its features idiopathic TTP or HUS, response to plasma therapy is poor. The overall mortality of patients afflicted with TA-TMA is about 80%. Comparative studies aimed at discovering risk factors for the development of TA-TMA and defined different entities according to clinical, laboratory and outcome parameters. It is thought to be of multifactorial aetiology with the central event of endothelial damage. Intensive chemotherapy and radiation for bmt-preparation, infection in the immunocompromised host and graft versus host disease in conjunction with immunosuppressive therapy i. e. cyclosporine turn the haemostatic balance into a procoagulant state. Therapeutic strategies deduced from idiopathic TTP were disappointing with the only consensus in the withdrawal of cyclosporine from TA-TMA patients. Future trials are directed to ameliorate endothelial dysfunction.