[Role of enteric Klebsiella pneumonia infection and HLA-B27 in ankylosing spondylitis].

Klebsiella pneumonia (KP) infection and HLA-B 27 have been shown to be strongly associated with ankylosing spondylitis (AS). In the present study, faecal cultures were performed and showed faecal carriage rate of KP was much higher in patients with AS (10/30) and hospital volunteers (2/10) than in the non-hospital volunteers (0/20). An octadecapeptide encompassing the shared hexamer between HLA-B 27 and KP nitrogenase residue was synthesized and autoantibodies against this short peptide were detected in sera of patients with AS and Reiter's syndrome (RS) and other related disease and normal controls. The results showed that such autoantibodies were detected in 42.2% of AS and 30% of RS patients yielding positive rate much higher than those found in other control groups. It is concluded that enteric KP infection were strongly implicated in the pathogenesis of AS probably by the mechanism of molecular mimicry with HLA-B 27.