[Antibodies to Klebsiella pneumoniae in ankylosing spondylitis].

This study was performed to evaluate the involvement of Klebsiella pneumoniae (Kp) in ankylosing spondylitis. Serum IgA, IgG and IgM antibodies to Kp were measured with ELISA in 60 patients with ankylosing spondylitis (AS), 28 patients with rheumatoid arthritis (RA) and 45 healthy individuals. A marked elevation of IgA antibody to Kp was detected in the sera of patients with AS, compared to that in patients with RA (P < 0.02) and healthy controls (P < 0.001). The positive rate of antibodies to Kp was 55% in patients with active AS, significantly higher than that in patients with inactive AS (16.7%, P < 0.01), patients with RA (17.8%, P < 0.05) and healthy controls (4.4%, P < 0.001). Stool culture for Kp was carried out in 15 of the 60 patients with AS simultaneously, 3 (20%) of them were positive. Our results are in line with the previously published findings suggesting that Kp may play a role in the pathogenesis of AS.