Plasma Exchange for Platelet Alloimmunization

We studied the effectiveness of plasma exchange for reversing antiplatelet alloimmunization in 18 patients undergoing marrow transplantation. Patients received one-to-three daily exchanges. Most exchanges occurred during the pretransplant conditioning phase. Overall, eleven of 18 patients had a beneficial response to plasma exchange, defined as an improvement in post-platelet-transfusion increments. More patients responded who had received two or more exchanges. Patients who had lymphocytotoxic antibodies pretransplant were more likely to benefit from the exchange. Our results show that plasma exchange may improve the posttransfusion platelet increments in alloimmunized patients undergoing marrow transplant.