Detection and characterization of immune complexes by the platelet aggregation test. II. Circulating complexes.

Abstract

Model experiments with preformed antigen–antibody complexes have shown that the platelet aggregation test can be used to characterize immune complexes. The platelet aggregating activity of four sera behaved like antigen–antibody complexes with respect to the effect of added antigen, added antibody and sedimentation in density gradient centrifugation. Two of the sera were from patients with fever of unknown origin. The findings suggest that the two sera contained circulating immune complexes which had both measles hyperimmunization induced and normal specificities. The serum of a patient with fatal subacute hepatitis seemed to contain immune complexes with Australia antigen. It was also positive in many of the autoimmunity tests. One of the sera was from a patient with haemorrhagic varicella in the acute phase of the disease. The patient had received large amounts of γ-globulin. The results suggested the transient presence of circulating immune complexes with varicella specificity.