Serial studies on circulating immune complexes in post-streptococcal sequelae

Abstract

Levels of circulating immune complexes were determined in the Trinidadian population with a high incidence of acute post-streptococcal sequelae, acute rheumatic fever and acute post-streptococcal glomerulonephritis. The studies were done on acute phase and serial bleedings up to 6 months after the acute illness. C1q solid phase assay employing radiolabelled protein A and the Raji cell radioimmunoassay were used in the detection of immune complexes. Both groups of patients had significantly elevated levels of immune complexes during the acute phase and showed an equivalent decline to slightly elevated levels during the 6 months of observation. The incidence and molecular size of the immune complexes in the two post-streptococcal sequelae were equivalent. The Raji cell assay tended to show much higher levels of complexes on an absolute basis, but both assays demonstrated an equivalent decline from the acute phase. These studies suggest that the presence of equivalent levels of complexes in two entirely different post-streptococcal sequelae indicates that other factors, such as the nature of the antigen in the complex, are more important in the pathogenesis of the post-streptococcal sequelae than the actual presence or the absolute levels of complexes.