Role of polymorphisms in the interleukin-10 gene in determining disease susceptibility and phenotype in inflamatory bowel disease

Interleukin-10 (IL-10) has a key role in regulating mucosal inflammation. T he role of functional polymorphisms at positions -627 and -1117 in the IL-1 0 gene as candidate susceptibility loci in inflammatory bowel disease and t heir importance in determining disease extent were evaluated in 159 patient s with ulcerative colitis (83 left-sided; 76 extensive), 90 patients with C rohn's disease (22 small bowel; 29 large bowel; 39 both), and 227 controls. Genotyping was performed either by PCR RFLP assays (-627 site) or SSCP ana lysis (-1117 site). An excess of -627A allele was observed in patients with left-sided colitis (52%) compared with controls (33%; P = 0.004) suggestin g that IL-10 may influence the extent of the disease. These results were no t replicated in a newly recruited group (N = 100) of patients with UC. We c onclude that polymorphisms at -627 and -1117 sites in the IL-10 gene do not contribute to the susceptibility to IBD or determining the extent of the d isease in our population.