Since the past, some genetic backgrounds have been pointed out as one of a cause of inflammatory bowel disease (colitis ulcerative, Crohn's disease). There genetic backgrounds include HLA typing and genotype of polymorphism site of cytokine genes. It is for a purpose of this study to make clear genetic factors of the susceptibility of inflammatory bowel disease in Japanese. We examined the association between inflammatory bowel disease and TNF gene, TNFRSF1A gene, TNFRSF1B gene, and IL18 gene. Furthermore, we studied it on CARD15/NOD2 gene. We found a significant difference in carrier frequency for haplotype AT (1466 A, 1493 T) of the TNFRSF1B gene between CD patients and the controls. The significance proved to be greater in CD patients with both internal and external fistula, and in those who were poor responders (n=22) to our treatments, which consisted of nutritional therapy, medical therapy and surgical therapy. In patients with Crohn's disease, the frequency of TCC-allele carriers was significantly higher than in healthy controls. And the magnitude of the association was more remarkable in females. The TCC-allele at codon 35 of IL18 may increase the risk for Crohn's disease, especially in females. It was reported that CARD15/NOD2 gene variants related to Crohn's disease in Europe and America in 2001. However, the same variants was not detected in Crohn's disease patient in Japan. Now we have been detecting CARD15/NOD2 genetic new variants. We have to make clear how CARD15/NOD2 gene variants is related to the onset of inflammatory bowel disease in Japanese.
