Cytokine mRNA expression pattern in horses with large intestinal disease

The aim of this study was to investigate cytokine expression patterns in the large intestinal mucosa of horses, particularly in diseases associated with inflammation. Many cases of equine colitis remain without a definitive diagnosis and survival rates are poor. In humans, colitis is associated with increased expression of pro-inflammatory cytokines. To examine if similar responses occur in horses, we investigated IL-2, IL-4, IL-5, IL-10, TNFalpha, IFNgamma and TGFbeta messenger RNA expression in large intestinal mucosa. Samples were obtained from animals with large intestinal disease (n = 15) or from horses which had different levels of cyathostomin infection (n = 9) and analysed by reverse transcription-polymerase chain reaction. IL-2 was detected at all sites, whilst IL-4 was detected at all but one site. The presence of IL-10, IL-5, IFNgamma and TGFbeta varied with no significant differences amongst groups (P > 0.4). Detection of TNFalpha was significantly different between the group of horses that had infiltrative inflammatory bowel disease and those with larval cyathostominosis (P = 0.028) and those that were helminth negative (P = 0.014). These results indicate a possible role for TNFalpha in the pathogenesis of equine infiltrative inflammatory bowel disease. (C) 2002 Published by Elsevier Science Ltd.