Antibodies to Klebsiella pneumoniae lipopolysaccharide in patients with ankylosing spondylitis

The role of microbial lipopolysaccharides (LPS) in the aetiopathogenesis of ankylosing spondylitis (AS) is a matter of continuing debate. In this stud y, class-specific IgG, IgA and IgM antibodies against Klebsiella pneumoniae , Escherichia coli, Salmonella typhimurium and Salmonella enteritidis LPS w ere measured by enzyme-linked immunosorbent assay (ELISA) in 100 AS patient s, 50 rheumatoid arthritis (RA) patients and 50 healthy control subjects. T he AS patients had significantly elevated levels of IgG and IgA antibodies against IL pneumoniae LPS (P < 0.001) and IgA antibodies against E, coli LP S (P < 0.05) compared to healthy controls. There were no significant elevat ions of antibody levels against S. typhimurium and S. enteritidis in the th ree study groups. In addition, there was a correlation between IgG and IgA anti-IL pneumoniae LPS antibody levels and the acute-phase reactant C-react ive protein (P < 0.001).