Polymorphisms of the IL-1β and IL-1β-inducible genes in ulcerative colitis

Background. Ulcerative colitis (UC) is a chronic disorder of undetermined etiology, but a genetic predisposition to UC is well recognized. Among cytokines induced in UC, interleukin 1 (IL-1) appears to have a central role because of its immunological upregulatory and proinflammatory activities. The aim of this study was to assess whether UC is associated with polymorphisms of the IL-1β gene and three additional genes inducible with IL-1β in Japanese subjects. Methods. A total of 96 patients with UC and 106 ethnically matched controls were genotyped at polymorphic sites in IL-1β, matrix metalloproteinase 1 (MMP-1), matrix metallo-proteinase 3 (MMP-3), and inducible nitric oxide synthase (iNOS) genes, using polymerase chain reaction (PCR)-based methods. Results. There was no significant difference in genotype distributions of IL-1β, MMP-1, MMP-3, and iNOS genes between controls and UC patients in a Japanese population. Also, no significant association of those polymorphisms with various clinical parameters of the patients was found. However, concerning association of age at onset with clinical factors in UC, the frequency of pancolitis was significantly higher in UC patients with age at onset being less than 30 years than in those more than 30 years of age (P = 0.049). Conclusions. No association of the IL-1gB and three IL-1gB-inducible gene polymorphisms with UC was observed in a Japanese population.