Objective: To explain the correlation between HLA class II genes and the intractability of ulcerative colitis (UC), DR genotyping and clinical analysis were performed for patients with UC.
Methods: HLA-DRB types and HLA-DR2 subtypes of 45 patients with UC in our hospital were determined using molecular genotyping in combination with sequence-specific oligonucleotide hybridization by polymerase chain reactions. The extent of involvement, clinical course, and treatment were studied to evaluate the intractability of UC.
Results: The gene frequency of DRB1*1502 in 18 patients with total colitis (0.444) was significantly higher than the group with left-sided colitis and proctitis (0.148; p < 0.05). In addition, DRw11 and DR2 increased significantly in the group including 18 cases with total colitis. In the 11 patients with total colectomy there were no cases with DRB1*1501, whereas 34 patients without operation included 12 genes of DRB1*1501 (p < 0.05). In addition, DRw11 increased significantly in the group with total colectomy compared to the group without operation (p < 0.05). When comparing between patients with and without intractability (defined based on the Japanese definition), DRB1*1502 and DRw11 were found more frequently in intractable UC patients (p < 0.01), whereas DRB1*1501 increased significantly in cases without intractability (p < 0.05).
Conclusions: DRB1*1502 or DRw11 have a probability of being closely related to the intractability of UC. In addition, patients with UC possessing DRB1*1501 have a lower probability of their cases leading to intractable UC. Thus, we believe there are unknown genes present that encode the intractability of UC.