Immunfluoreszenzmikrophotometrie zur quantitativen Erfassung antithrombozytärer Autoantikörper

In vitro tests for platelet compatibility

Four methods were investigated to determine their suitability as platelet compatibility procedures: leukoagglutination, lymphocytotoxicity, platelet suspension immunofluorescence and platelet enzyme-linked immunosorbant assay. None of the tests were found to reliably predict the 24-hour-posttransfusion platelet increment in 8 refractory thrombocytopenic patients judged refractory to random donor platelet therapy.

Detection of platelet antibody using rosette technique with anti-IgG antibody-coated polyacrylamide gel: a preliminary report

Paraformaldehyde-fixed platelets from normal donors were used for detection of antibody to platelet by in vitro sensitization (indirect method) utilizing rabbit anti-human IgG heavy chain specific antibody-coated polyacrylamide gels (Immunobeads). The sensitized platelets formed rosettes with Immunobeads and the positive rosette count was over 30%, while control showed less than 8% when normal sera were used. This method was also applicable for detecting antibody-sensitized platelets in vivo (direct method) in patients with autoimmune thrombocytopenia. This method is simple, rapid and reproducible for clinical use. Direct and indirect immunofluorescent antibody tests and a blocking test with anti-human serum also supported the results of Immunobead rosetting technique.

The problem of platelet autoantibodies. I. Evaluation of the platelet factor 3 availability test for their detection

To assess two modifications of the platelet factor 3 (PF3) test for platelet antibody detection, an analysis of test conditions was performed with normal test material (serum, plasma, globulin fraction), defined HLA-specific, complement-fixing antisera and a quinidine-induced antiserum. It was shown that, under standardized conditions, the PF3 test revealed known platelet antibodies confirming earlier results. Its reproducibility and, to a lesser degree, its sensitivity were inferior to platelet complement fixation. In contrast, the test did not permit the reliable determination of platelet autoantibodies in sera of 89 thrombocytopenic patients including 36 cases of idiopathic thrombocytopenic purpura. Positive results loosely corresponded to the presence of HLA antibodies in sera.

Immune reactions of platelets and their clinical significance

It is recognized that blood platelets with a peculiar cell membrane which carries numerous genetically determined immunogens, but is also intricately associated with the hemostatic process not only participate in immune reactions as a passive target cell, but also as an active functional cell. Pertinent results of animal experiments and of in vivo and in vitro investigations with human blood platelets are reviewed in the attempt to elucidate the role of immune reactions of platelets in the pathogenesis of various human bleeding disorders.