Objective: Associations between HLA-DR genotypes and susceptibility to Crohn's disease (CD) have been reported. However, it is not known whether certain HLA-DR genotypes or IL-1ra gene polymorphism are associated with responsiveness to treatment or different clinical patterns of disease.
Design/setting: In a large, randomized, controlled multicentre trial, 318 patients with CD were treated with daily doses of 6, 9 or 18 mg budesonide. Patients were stratified into two groups: patients without steroid pretreatment and with active CD (CDAI > 150) and patients with conventional steroid pretreatment of < or= 30 mg prednisolone per day, which was replaced by oral budesonide within 3 weeks.
Main outcome measures: The HLA-DRB1 genotypes 1-16 and the IL-1ra gene polymorphism were examined for an association with budesonide treatment failure.
Results: Only HLA-DR 8 was associated with treatment failure of budesonide. HLA-DR 8 is not very common. Only 17/243 patients who could be evaluated expressed this genotype, and 13 of these 17 patients did not respond to budesonide (P < 0.00067). Neither the other HLA-DR genotypes nor the IL-1ra gene polymorphism had an influence on treatment outcome of budesonide therapy. No significant association of fistulas, perianal disease, need for bowel resections, and disease localization with certain HLA-DRB1 genotypes or the IL-1ra gene polymorphism were found.
Conclusions: This is the first description of an association of a certain HLA-DR genotype (HLA-DR 8) with treatment failure in inflammatory bowel disease (IBD).