FAILURE OF PLATELET TRANSFUSION TO IMPROVE HUMAN RENAL ALLOGRAFT SURVIVAL

Abstract

Platelets, expressing only class I antigens on their surface, have been shown to improve renal allograft survival in some experimental models but do not lead to humoral sensitization. In this pilot study, 24 previously untransfused patients were given 3 platelet transfusions at 2-week intervals before renal transplantation. Twelve patients (group 1) received 200 108 platelets contaminated by 15 106 leukocytes in each transfusion, and 42% developed cytotoxie antibodies; 12 further patients (group 2) received a purified preparation containing 200 108 platelets and <5 l06 leukocytes, and no cytotoxic antibodies were detected. Using a more sensitive flow cytometry technique, 83% of group 1 but only 17% of group 2 (P<0.004) responded to their platelet donors. From each group 9 patients have been transplanted. Four grafts in group 1 and 6 in group 2 have failed, yielding a 1-year graft survival rate of 44%, compared with 69% in blood-transfused patients (P = 0.03). Pure platelet transfusions, using our protocol, do not appear to improve renal allograft survival, and minimal contamination by leukocytes can lead to humoral sensitization.