Severe thrombotic microangiopathy: an infrequent complication of bone marrow transplantation. Gruppo Italiano Trapianto Midollo Osseo (GITMO).

Thrombotic microangiopathy (TMA) usually occurs during the first weeks following transplantation in the setting of systemic infections or graft-versus-host reaction. However, some cases without any evidence of other complications or after autologous transplantation have been reported. Transplant-associated TMA (BMT-TMA) incidence ranges from 0% to 74%, possibly due to different diagnostic criteria. The GITMO Group provided the opportunity to retrospectively study 4334 consecutive Italian patients who received bone marrow transplants (1759 allogeneic and 2575 autologous BMT), during the 1985-1995 period. The present report focuses on patients with severe TMA requiring specific treatment. We identified nine cases of TMA as a complication of allogeneic BMT (0.51%), whereas three patients developed the syndrome after ABMT (0.13%); four of the 12 patients were not receiving CsA at the time of TMA onset. Finally, it is noteworthy that TMA occurred in seven patients as a late complication (up to 90 days after BMT). Despite intensive treatment, five of the seven patients with thrombotic thrombocytopenic purpura died. One death was observed among the five cases with hemolytic uremic syndrome.