LEUKOCYTE REDUCTION AND ULTRAVIOLET-B IRRADIATION OF PLATELETS TO PREVENT ALLOIMMUNIZATION AND REFRACTORINESS TO PLATELET TRANSFUSIONS

Background We conducted a multi-institutional, randomized, blinded tri al to determine whether the use of platelets from which leukocytes had been removed by a filter or that had been treated with ultraviolet B irradiation would prevent the formation of antiplatelet alloantibodies and refractoriness to platelet transfusions. Methods Patients who wer e receiving induction chemotherapy for acute myeloid leukemia were ran domly assigned to receive one of four types of platelet transfusions: unmodified, pooled platelet concentrates from random donors (control); filtered, pooled platelet concentrates from random donors (F-PC); ult raviolet B-irradiated, pooled platelet concentrates from random donors (UVB-PC); or filtered platelets obtained by apheresis from single ran dom donors (F-AP). All patients received transfusions of filtered, leu kocyte-reduced red cells. Results Of 530 patients with no alloantibodi es at base line, 13 percent of those in the control group produced lym phocytotoxic antibodies and their thrombocytopenia became refractory t o platelet transfusions, as compared with 3 percent in the F-PC group, 5 percent in the UVB-PC group, and 4 percent in the F-AP group (P les s than or equal to 0.03 for each treated group as compared with the co ntrols; there were no significant differences among the treated groups ). Lymphocytotoxic antibodies were found in 45 percent of the controls , as compared with 17 to 21 percent in the treated groups (P<0.001 for each treated group as compared with the controls; there were no signi ficant differences among the treated groups). Antibodies against plate let glycoproteins developed in 6 to 11 percent of the patients, with n o significant differences among the four groups. Conclusions Reduction of leukocytes by filtration and ultraviolet B irradiation of platelet s are equally effective in preventing alloantibody-mediated refractori ness to platelets during chemotherapy for acute myeloid leukemia. Plat elets obtained by apheresis from single random donors provided no addi tional benefit as compared with pooled platelet concentrates from rand om donors. (C) 1997, Massachusetts Medical Society.