Detection of immune complexes in acute rheumatic fever and their relationship to HLA-B5.

Employing five radioimmunoassays for immune complexes, the sera of 45 acute and 27 postacute follow-up sera from patients with acute rheumatic fever were examined. All patients experienced actue polyarthritis. Complexes were detected in 89% of acute-phase sera by one assay, 51% by two, 29% by three, and 7% by four. Immune complex values decreased significantly at followup, although some abnormalities persisted. There was no correlation between extra-articular manifestations and the occurrence of circulating immune complexes. Those positive for HLA-B5 demonstrated a significantly more pronounced immune response as measured by circulating immune complexes. The data indicate that circulating immune complexes occur frequently in adults with acute rheumatic fever. The relative frequency of immune complexes detected by multiple techniques in B5-positive, compared with B5-negative, patients suggests a genetic basis for the development of immune complexes in these patiemts.