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A patient with thrombotic thrombocytopenic purpura (TTP) showed for the first time catastrophic signs and symptoms of CNS involvement immediately after infusion of platelets. Postmortem examination revealed extensive deposits of platelet aggregates within the small blood vessels of the brain, whereas lesions elsewhere in the body consisted of platelets as well as fibrin and were associated with endothelial proliferation and microaneurysm formation. These findings are consistent with the view that the initial event in TTP may be platelet aggregation. The plasma of this patient contained platelet-aggregating activity. We conclude that platelet transfusions in patients with TTP may aggravate the disease process.

We worked with a new strategy for the treatment of autoimmune hemolytic anemia (AIHA) of the warm antibody type. Platelets were loaded with Vinca alkaloids and reacted with antiplatelet antibodies to facilitate their phagocytosis by macrophages, resulting in a measure of selective delivery of the drugs to the cells of the mononuclear phagocyte system, which destroy RBCs in AIHA. Four patients were studied. Three with AIHA refractory to splenectomy and the use of moderate doses of glucocorticoids achieved hematologic and clinical remissions. Administration of steroids was either discontinued or reduced to minimal doses after treatment. Remissions lasted three years in two patients and one year in the other. Responses were characterized by prompt prolongation of RBC survival, correction of anemia, and gradual decrease in cell-bound antibody. In one nonsplenectomized patient, the disorder did not respond. Platelet-Vinca alkaloid complex is useful in the treatment of AIHA refractory to splenectomy and use of steroids.