Yersinia antibodies in inflammatory joint diseases.

The occurrence of IgM, IgG and IgA class Yersinia antibodies was studied at the beginning of an inflammatory joint disease and one year later in 354 adult patients using an ELISA technique. The control groups consisted of age and sex matched healthy persons living in the same geographical area as the patients, and of 64 patients with chronic rheumatoid arthritis. Yersinia antibodies of any Ig class were found in 9.0% of all the patients at the beginning of the disease, in 4.0% of the healthy controls and in 1.6% of the patients with chronic rheumatoid arthritis. Patients with ankylosing spondylitis, Reiter's disease or other reactive arthritis showed the highest prevalence (19.4%) of Yersinia antibodies, but in the whole material one half of the patients with Yersinia antibodies were clinically classified as rheumatoid or nonspecific arthritis. The elevated prevalence of Yersinia antibodies in patients with probable rheumatoid or nonspecific arthritis may indicate a reactive etiopathogenesis of arthritis also in some cases without previous evidence of gastrointestinal infection. Quantitation of IgG and IgA antibodies to Yersinia is important in the diagnosis of Yersinia arthritis. These antibodies may not be detected by the generally used agglutination test.