ISOLATED THROMBOCYTOPENIA FOLLOWING ALLOGENEIC BONE MARROW TRANSPLANTATION

Abstract

Isolated thrombocytopenia following bone marrow transplantation was investigated in 65 fully grafted patients (pts) surviving 60 days post transplant. 24 pts (37%) developed this complication, which occurred most frequently in pts receiving pre-tx preparation with total body irradiation or busulfan. Two distinct syndromes were identified: (1) transient thrombocytopenia (9 pts) in which a normal platelet (plt) count (100,000/mm3) was established by day +40 but then fell to 10-45,000 on day +40-+70, with subsequent resolution by day +90. Three of these cases were associated with trimethoprim-sulfamethoxazole therapy. (2) chronic thrombocytopenia (15 pts) in which a plt count > 100,000 was not achieved at any time during the first 4 mo post-tx despite the simultaneous presence of normal granulocyte and reticulocyte counts. No association with drug therapy was detected. While the transient syndrome did not adversely affect prognosis, the chronic syndrome carried a high mortality (21% actuarial survival at 1000 days post-tx compared to 67% for all other pts p<0.01). The mortality was not due to bleeding but rather to a high association with both severe acute (grade III-IV) graft versus host disease and chronic GVHD. We conclude that isolated thrombocytopenia represents a significant complication of bone marrow transplantation particularly in pts receiving hematopoietic ablative preparatory regimens and that it is the chronic, and not the transient, thrombocytopenic syndrome that adversely affects patient prognosis as a manifestation of GVHD.