Common serological features in rheumatoid arthritis and yersinia arthritis. Demonstration of rheumatoid factors and antibodies against ssDNA and Yersinia enterocolitica Lipopolysaccharide by ELISA.

Sera from 31 patients with rheumatoid arthritis (RA) and from 49 patients with Yersinia enterocolitica 0:3 infection were examined for the presence of rheumatoid factors (RF) and antibodies against denatured (ss) DNA and Y. enterocolitica 0:3 lipopolysaccharide (LPS), by using enzyme-linked immunosorbent assays. Anti-ssDNA antibodies of IgG class were found equally often in the RA as in yersinia patients. The IgM-anti-ssDNA antibody levels were also elevated in the yersinia patients, whereas the RA patients had elevated levels of IgA-anti-ssDNA antibodies. High levels of RF were seen in the RA patients and an increase in IgA-RF activity was observed during the acute stage in the yersinia arthritis patients. An overlap in the serological profiles of RA and yersinia arthritis was further seen in th results of the anti-Y. enterocolitica LPS determinations, a anti-LPS antibodies of IgG class were present not only in yersiniosis but also in 16% of the RA patients.