Analysis of MHC class II DP, DQ and DR alleles in Crohn's disease.
BACKGROUND: Although inflammation in Crohn's disease is believed to be mediated by activated T cells, genotyping of all MHC class II alleles in white people with this disease has not been reported. AIMS: To perform a detailed molecular analysis of HLA DPB, DQB, and DRB genes in white patients with Crohn's disease and controls in order to determine if the inheritance of any class II genes confers susceptibility or resistance to this disease. METHODS: Complete molecular typing of HLA class II DPB, DQB, and DRB alleles was performed in 58 white patients with Crohn's disease and 93 healthy controls using a polymerase chain reaction-sequence specific oligonucleotide based approach. RESULTS: No significant association with any DPB or DQB alleles was noted in patients with Crohn's disease. Since our previous studies had shown a strong association of an HLA DRB3*0301/DRB1*1302 haplotype with Crohn's disease, we re-examined this association using more stringent genotyping criteria. This haplotype was present in 20.7% of patients and 5.4% of controls (p = 0.0066; relative risk = 4.59). CONCLUSIONS: The DRB3*0301/DRB1*1302 haplotype is the only significant MHC class II association noted in white people with Crohn's disease and represents the strongest association of any MHC or non-MHC locus with this disease.