Polymorphisms of the ICAM-1 gene are associated with inflammatory bowel disease, regardless of the p-ANCA status.

The intercellular adhesion molecule-1 ( ICAM-1) is of paramount importance for the initiation and propagation of various inflammatory conditions. An increased frequency of allele R241 of the ICAM-1gene was previously described in p-ANCA-negative as compared to p-ANCA-positive ulcerative colitisand vice versa in Crohn's disease. One hundred sixteen healthy unrelated controls, 121 patients with ulcerative colitis, and 96 patients with Crohn's diseasewere genotyped for two polymorphisms of the ICAM-1gene (R/G241, exon 4; and K/E469, exon 6), employing dot-blothybridization and stratified according to their p-ANCAstatus. When compared with the control group the frequency of the allele R241 (P = 0.024) and the heterozygous genotype R/G241, P = 0.032) were significantly increased in ulcerative colitis, whereas the homozygous genotype G/G241 was found less frequently (P = 0.022). The heterozygous genotype K/E469 was observed less frequently (P = 0.001 and 0.037, resp.) than the homozygous genotype E/E469, which was more frequent in Crohn's diseaseand ulcerative colitis(P = 0.002 and 0.012, respectively). Further significant differences concerning the allele or genotype distribution were not observed. After stratification for the p-ANCAstatus significant differences concerning the frequencies of both the R241 and the E469 alleles were not detected when p-ANCA-positive inflammatory bowel disease and p-ANCA-negative inflammatory bowel disease were compared. Ulcerative colitisand Crohn's diseaseare associated with polymorphisms of the ICAM-1gene, which might therefore represent a functional candidate gene. However, the observed associations are independent of the p-ANCAstatus.