To the Editor: Byrnes and Khurana1 conclude that, in a case of thrombotic thrombocytopenic purpura, remission was achieved by replacement of a deficient, “plasma factor” by transfusion of exogenous plasma. However, they do not convincingly exclude the possibility that the deficient factor was associated with platelets rather than plasma. The data presented on their patient indicate that the first seven successful exchange transfusions were done with fresh whole blood, which include normal fresh platelets. The patient improved, and despite receiving platelets, thrombotic tendencies were not aggravated. Furthermore, the interval between successive relapses varied from five to 11 days, a period.
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