Platelets: VII. Shortened "Platelet Survival Time" and Development of Platelet Agglutinins Following Multiple Platelet Transfusions.

Abstract

Original technics were employed for the prepn., preservation and admn. of large numbers of platelets, the study of their rate of disappearance from the circulation and the presence of antiplatelet substances in the serum. The rate of platelet disappearance or "platelet survival time" was followed at regular intervals in 4 patients with hypoplastic or aplastic anemia receiving repeated transfusions of platelet-rich polycythemic blood or plasma administered directly by means of a "Silicone technic" or collected in plastic containers or of isolated platelets as supportive therapy. In 3 of these patients it was noticed that the survival time of the platelets became shorter, until it was no longer than that observed in idiopathic thrombocytopenic purpura. Meantime, the effect of the platelet transfusions on the bleeding manifestations of these patients became less and less beneficial. A titer anti-platelet agglutinin was found in the serum of 1 of these patients. With similar technics, the presence of agglutinins against platelets in the serum of some cases of idiopathic thrombocytopenic purpura. A search for platelet agglutinin was conducted in the serum of 11 patients who had received weak platelet agglutinin. This patient developed thrombocytopenia and exhibited a reduced "platelet survival time" when compared to normal individuals. Thus, "refractoriness" to the therapeutic effect of the admn. of platelets may develop in patients receiving multiple platelet transfusions. This may be due to changes in severity of the fundamental disease, but, at least in selected cases, may be due to the development of "acquired platelet agglutinins." These results support the view that the mechanism of some cases of idiopathic thrombocytopenic purpura may be the development of anti-platelet substances through "iso-immunization".