Pan-reactive platelet antibodies in post-transfusion purpura

Background and Objectives: The mechanism for the destruction of a patient's own platelets in post-transfusion purpura (PTP) is unknown. In order to te st the hypothesis that the destruction of autologous platelets in PTP is re lated to the presence of platelet antibodies with pan-reactivity, we invest igated sera from patients with PTP, Materials and Methods: Sera from 12 pat ients with PTP were investigated for platelet antibodies by platelet-ELISA and monoclonal antibody-specific immobilization of platelet antigen assay. Results: During the thrombocytopenic phase, antibodies of IgG and IgM class es with pan-specificity against platelet GPIIb-IIIa, GPIb-IX and GPIa-IIa w ere found together with HPA alloantibodies. After recovery, the pan-specifi c antibodies disappeared or the extent of reactivity diminished, whereas th e IgG HPA alloantibodies persisted, Conclusion: These findings provide evid ence that transient pan-reactive antibodies may be responsible for the auto logous platelet destruction in PTP.