The problem of thrombocytopenia after hematopoietic stem cell transplantation.

Thrombocytopenia after hematopoietic stem cell transplantation (HSCT) is associated with an increased risk of bleeding and utilization of significant resources. This review presents an analysis of risk factors associated with delayed platelet engraftment. The retrospective analysis included 1,468 recipients of autologous or allogeneic transplants treated between January 1, 1990 and July 1, 1995. Risk factors associated with delayed platelet engraftment after autologous HSCT included use of marrow rather than peripheral blood as the source of stem cells, being transplanted for acute myeloid leukemia rather than other diseases, positive patient serology for cytomegalovirus and the presence of infection post-transplant before engraftment. Risk factors associated with delayed platelet engraftment after allogeneic marrow transplantation included unrelated as opposed to related donor transplants, being transplanted for diseases other than chronic myelogenous leukemia, increased age, onset of acute graft-versus-host disease (AGVHD), male gender, the administration of methotrexate for GVHD prophylaxis and the presence of infection before engraftment. Delayed platelet recovery is associated with decreased survival after both autologous and allogeneic transplants. Management of delayed platelet recovery by transfusion of blood products requires significant medical resources and is of some risk to the patients. Further development of new strategies may safely reduce the need for blood products. These include peripheral blood stem cell transplants (allogeneic and autologous), new algorithms for administering routine platelet transfusions and investigative biological agents for stimulating megakaryocytopoiesis. Further studies may elucidate the cause of increased platelet consumption associated with infection and GVHD.