Serum antibodies to Klebsiella capsular polysaccharides in ankylosing spondylitis.

Objective: To measure antibodies to Klebsiella capsular polysaccharides in the sera of HLA-B27 positive patients with ankylosing spondylitis (AS), compared with HLA-B27 positive and HLA-B27 negative healthy control subjects.

Methods: Antibodies were detected by means of an enzyme-linked immunosorbent assay specific for each of the 77 known Klebsiella serotypes.

Results: Significantly elevated frequencies and titers of antibodies to capsular polysaccharides K26, K36, and K50 were detected in sera from AS patients, compared with controls.

Conclusions: These results suggest the predominance of Klebsiella serotypes K26, K36, and K50 in patients with AS.