Platelet transfusion therapy and circulating immune complexes.

30 platelet transfusions were administered to 9 thrombocytopenic patients with acute leukemias. Using the Raji cell radioimmunoassay, the serum concentration for circulating immune complexes (CIC) were determined immediately before and 10--12 h after each transfusion therapy. Elevated serum concentrations for CIC were present in 14 of the pretransfusion samples. After platelet transfusion therapy, a significant (p < 0.02) decrease in the values of CIC occurred. In these 14 transfusion studies the mean percent platelet increment was considerably lower (0.10 > p > 0.05) than the mean for the 16 transfusion studies in which the pretransfusion values for CIC were normal. These results show that CIC probably play an important role in removing transfused platelets from the circulation. Conversely, platelets are able to remove CIC from the circulation.