ASSOCIATION OF GUT INFLAMMATION WITH INCREASED SERUM IGA CLASS KLEBSIELLA ANTIBODY CONCENTRATIONS IN PATIENTS WITH AXIAL ANKYLOSING-SPONDYLITIS (AS) - IMPLICATION FOR DIFFERENT ETIOPATHOGENETIC MECHANISMS FOR AXIAL AND PERIPHERAL AS

Objectives - A role for Klebsiella pneumoniae in ankylosing spondyliti s (AS) has been suggested because faecal carriage of Klebsiella and se rum Klebsiella specific antibodies may be increased in this disease. T his study has extended the earlier findings by comparing Klebsiella sp ecific serum IgA class antibodies with inflammatory changes in the gut . Methods - IgA antibodies to K pneumoniae, Escherichia coli, and Prot eus mirabilis in serum samples of 25 patients with AS, of eight contro l patients, and of 100 healthy blood donors were measured by enzyme im munoassay. Gut inflammation of the patients was studied by ileocolonos copy. Results - Increased IgA antibody concentrations to K pneumoniae associated with gut inflammation in patients with axial form of AS. Su ch association was not seen in patients with peripheral form of AS. Co nclusions - These findings may provide further evidence for the role o f K pneumoniae in the pathogenesis of AS. However, at least some of th e patients with axial AS without gut inflammation, as well as patients with peripheral AS did not have increased K pneumoniae antibody conce ntrations, which may be regarded as evidence against the direct role o f K pneumoniae in the pathogenesis. The aetiopathogenetic mechanisms i n the axial and peripheral form of AS may be different.