A Hypertransfused Mouse Assay for Thrombopoietic Factors

A method was developed for the quantitative separation of platelets from CF1 mouse whole blood. This made it possible to determine the platelet incorporation of ³⁵S-sulfate without the necessity of doing platelet counts. Daily hypertransfusions of the mice to three to four times normal platelet levels for 4-5 days significantly reduced platelet uptake of radiosulfate to an average of about 40% of the nontransfused controls. Mice rendered thrombocytopenic 48 hr earlier by antiplatelet serum, had 2-day ³⁵S uptakes over 2 1/2 times the controls and 6 times the hypertransfused animals. The administration of a total of 2 ml of serum, given twice daily for 3 days from a thrombocytopenic patient with Hodgkin's disease caused a highly significant 103% rise in radiosulfate incorporation when compared with saline in the hypertransfused mouse. Normal human serum from a healthy donor caused a small and insignificant rise. The serum from a patient with Hodgkin's disease caused a highly significant 63% rise in ³⁵S incorporation when compared to the normal serum.