Effect of sulphasalazine on gastrointestinal microflora and on mucosal heat shock protein expression in patients with rheumatoid arthritis.

This study was performed in order to elucidate a possible association between mucosal heat shock protein expression, the gastrointestinal microflora and disease activity in 17 patients with RA before and after 16 weeks of sulphasalazine (SASP) treatment. The duodenal-jejunal mucosal binding of the monoclonal antibody ML30, recognizing the 65 kDa heat shock protein of mycobacteria, was increased (P = 0.048) in the untreated RA patients compared to controls, but did not correlate to disease, activity or microflora and was not altered by SASP therapy. There was no convincing evidence for bacterial overgrowth in the jejunum and the faecal microflora was normal. SASP treatment altered the faecal microflora, with significant reductions of the total aerobic bacteria, Escherichia coli and Bacteroides, and increased numbers of Bacillus. SASP had only minor effects on the jejunal microflora. A high carriage frequency of Candida albicans was found in saliva and the counts correlated negatively with the unstimulated whole salivary secretion rate. These results suggest that the gut may be involved in the aetiopathogenesis of RA but do not substantiate the hypothesis that the anti-rheumatic effects of SASP are mediated via its anti-microbial properties. However, the possibility that a micro-organism, not detected in this study, may be of crucial importance in RA, cannot be ruled out.