The clinical significance of immune reactions with some streptococcal antigens in rheumatoid arthritis.

The level of antibodies and delayed-type hypersensitivity to the group specific polysaccharides and cell wall proteins of groups A, B, C and G streptococci was determined in 247 patients with rheumatoid arthritis (RA) as well as in healthy persons and in patients with other articular disorders by means of an enzyme linked immunosorbent assay, passive hemaglutination and leukocyte migration inhibition tests. An increase of the immune response to antigens of group B streptococcus was found in patients with RA. The greatest sensitization against these antigens was typical for high disease activity of short duration, and a rapidly progressive course of RA. High titers of antibodies to polysaccharide of group B streptococcus appeared in the synovial fluid in the early stages of the clinical development of RA. Values of immune response to streptococcal antigens correlated well with the titer of rheumatoid factor and the concentration of immunoglobulins and immune complexes. The presence of group B streptococcus in the urogenital tract appeared more often in patients with RA than in healthy persons. The possibility of a triggering role for immune reactions with antigens of group B streptococcus in the immunopathological process of RA is discussed, as well as the diagnostic significance of our results.