[Immunologic aggregation of human blood platelets and its inhibition in vitro].

Unwashed human thrombocytes are best suitable for the immunological activation in PBS-glucose solution. The immunological aggregability of the blood platelets increases in this solution up to more than 1 hour. Rabbit-anti-human-Ig-L-chain (chi) or -anti-human-C1q serum aggregate once washed thrombocytes. The combined application of both antisera has a potencive effect. Soluble human-IgG-rabbit-anti-human-IgG-antibody-F(ab')2-complexes produce a strong thrombocyte aggregation in an intermediate human IgG excess. 4 minutes past heating of human IgG at 63 degrees C a mixture of IgG aggregates (AHGG) arises which activates blood platelets maximally. The AHGG can be stored at -20 degrees C up to at least 4 weeks. Therapeutical aspirin concentrations inhibit the AHGG induced thrombocyte aggregation. Plasma from patients with idiopathic thrombocytopenia inhibits the AHGG mediated platelet aggregation less than plasma from healthy persons.