Association of Clinical Features with Human Leukocyte Antigen in Japanese Patients with Ulcerative Colitis

【Background】 The human leukocyte antigen (HLA) region has been found to be involved in the pathogenesis of inflammatory bowel disease (IBD), which is classified into ulcerative colitis (UC) and Crohn’s disease (CD), by genome-wide association studies. The aim of this study was to confirm whether HLA-alleles confer susceptibility to UC and to determine whether HLA-allel1es are associated with the clinical phenotypes in Japanese patients with UC. 【Methods】 In this study, HLA typing was performed by PCR-sequence-specific oligonucleotides (PCR-SSO) to confirm the correlation between UC and HLA alleles (for HLA-A, B, DRB1) in 45 Japanese UC patients. In addition, whether the HLA alleles are related to patient and clinical background characteristics was examined. 【Results】 Overall, 62.2%, and 66.7% of the 45 UC patients had HLA-B*52 and HLA-DRB1*15, respectively. These allele frequencies were significantly higher than in previously reported Japanese control persons (P < 0.0001). The frequencies of extraintestinal manifestations [odds ratio (OR) = 0.12, P = 0.039] and a history of colectomy (OR = 0.18, P = 0.046) were lower in HLA-B*52-positive UC patients than in HLA-B*52 negative UC patients. The white blood cell (WBC) count was significantly higher in HLA-DRB1*15-positive patients (9430 ± 4592/μL) than in HLA-DRB1*15-negative patients (6729 ± 2160/μL). Thus, HLA-B*52 and DRB1*15 appear to be associated with disease features and severity in Japanese UC patients. 【Conclusion】 These results indicate that HLA-B*52 and DRB1*15 are not only associated with overall UC susceptibility, but also with the clinical phenotypes in Japanese patients.