The role of alloimmunization in platelet survival studies.

The role of platelet alloimmunization in the survival of 51Cr-labeled allogeneic platelets was investigated in 89 patients with severe thrombocytopenias. The serological analysis included HLA typing of patients, screening of their sera in the lymphocytotoxicity test (LCTT), the platelet complement fixation test (PCFT), and the platelet radioactive anti-IgG test (PRAT; N = 38). Platelet donors were selected according to the best available HLA match and crossmatch in LCTT. Alloantibodies against HLA antigens were found in the sera of 17 patients (19.1%). No platelet-specific alloantibodies were detected. The use of compatible, allogeneic platelets permitted the discrimination of diminished platelet production from increased platelet turnover in thrombocytopenic patients with proven alloimmunization. Our results stress the necessity of a serological workup prior to platelet survival studies.