PROBLEM OF DEMONSTRATING ANTITHROMBOCYTIC AUTOANTIBODIES . COMPARATIVE ASSAY OF THROMBOCYTOPENIC AND NON-THROMBOCYTOPENIC PATIENTS BY ANTIGLOBULIN CONSUMPTION AND ANTIGLOBULIN FLUORESCENCE

The blood of 161 patients with different internal diseases was investigated with the direct and/or the indirect antiglobulin consumption test (AGCT) and with the direct and/or indirect fluorescence antiglobulin test (FT) on platelets. 63 patients revealed thrombocytopenia (platelets less than 90000 per mm3) in the course of various diseases, the remainder had normal platelet counts. Irrespective of clinical diagnosis positive results were found in the thrombocytopenic group in 37% with the direct AGCT, in 18% with the direct FT, in 27% with the indirect AGCT and in 28% with the indirect FT. Patients with normal platelet numbers showed positive tests in 30% (direct AGCT), in 16% (direct FT), in 7% (indirect AGCT) and in 9% (indirect FT). Control examinations on thrombocytes of healthy blood donors were almost regularly negative under the same conditions. These results suggest that the tests used for the detection of antiplatelet autoantibodies" are severely influenced by non-immunologic factors. There seem to exist correlations between the results of the tests and the level of gammaglobulins in the plasma. © 1968 Springer-Verlag."