Factors associated with response to platelet transfusion following hematopoietic stem cell transplantation.

We studied 526 consecutive post-transplant platelet transfusions to determine the factors associated with response to platelet transfusion in the BMT setting. Poor responses to platelet transfusions occurred frequently, with 310 of the 484 evaluable transfusions (64%) resulting in post-infusion corrected count increments of less than 7500. Factors associated with poor response to platelet transfusion by both univariate and multivariate analysis included, (1) presence of serum lymphocytotoxic antibodies; (2) male sex; (3) body surface area greater than 1.7 m2; (4) transfusion of red cells on the day of the platelet infusion; (5) concurrent administration of steroids; (6) major ABO mismatch between the recipient and the platelet product; and (7) (among women) a history of one or more pregnancies prior to transplant. Paradoxically, a history of greater than 25 blood product exposures prior to transplant, and evidence of prior CMV infection in either the bone marrow donor or recipient were associated with higher CCIs by both univariate and multivariate analysis. Factors that showed little correlation with response to platelet transfusion included, (1) age of the infused platelet product; (2) concurrent fever; (3) recent administration of intravenous immunoglobulin; and (4) absolute neutrophil count at the time of the infusion. The factors associated with response to platelet transfusion in BMT patients appear to be different from those observed in the non-transplant setting.