Demonstration of a thrombocytopenic factor in the blood of patients with thrombocytopenic purpura. 1951.

Abstract A thrombocytopenic factor has been demonstrated in the whole blood and plasma from eight of ten patients with idiopathic thrombocytopenic purpura and from one of three subjects with secondary thrombocytopenia. Administration of 500 c.c. of citrated whole blood or its plasma equivalent from these nine patients caused a prompt, and often dramatic decrease in the platelet counts of nonthrombocytopenic recipients. The thrombocytopenic effect persisted for five to seven days and, when severe, was associated with a prolonged bleeding time and decreased prothrombin consumption. The factor was stable for at least nine days at 5 ° C, and for at least eight days at 25 ° C. In the one plasma fractionation that has so far been done, the thrombocytopenic factor was found in the globulin fraction. Two patients who were demonstrated to have the platelet-reducing factor prior to splenectomy still had the factor present after platelet counts had returned to normal following removal of the spleen.