Role of heat shock proteins in the pathogenesis of arthritis associated with ulcerative colitis

ABSTRACT

Arthritis is a well recognised association of inflammatory bowel diseases. The cause of this arthritis is not yet clear but it is likely to be an immunological reaction to one of many bacterial antigens to which the bowel are exposed. One of such group, the heat shock proteins [HSPs], was investigated. These are immunodominant antigens of a wide variety of infectious microorganisms and have varying amino acid chain sequences some of which are similar to those found in human tissues. Antibodies to human HSP 60 and HSP 90 were measured in the serum of patients with ulcerative colitis, with and without arthritis, and in normal age and sex matched healthy controls. The severity of ulcerative colitis was assessed during exacerbation by numbers of motions per day, weight loss, pulse, temperature, ESR and serum albumin. The nature of the organisms colonising the large intestine was determined by bacteriological examination of stool. Higher mean titres of serum IgG anti-human HSP 60 and HSP 90 antibodies were found in all patients with ulcerative colitis than in healthy controls. Both types of antibodies were higher in patients in whom the intestine were colonised with E. coli. In these ulcerative colitis patients, serum IgG anti-human HSP 60 and HSP 90 antibodies were found to be higher in arthritic patients than in non arthritic and the elevation in anti-human HSP 60 antibodies was found to be significant. These findings suggest that arthritis associated with ulcerative colitis despite, being seronegative for rheumatoid factor, was associated with more sever ulcerative colitis and with a greater inflammatory response to heat shock proteins