Association of HLA-DRB1^*0803 and ^*1602 with the susceptibility to primary biliary cirrhosis

Forty-eight patients with primary biliary cirrhosis (PBC) and 336 healthy individuals were examined for HLA-DR, DQ and DP alleles, by DNA typing based on the polymerase chain reaction (PCR) sequence-specific oligonucleotide probe (SSOP) method. Frequencies of HLA-DRB1^*1602, DRB1^*0803, DQB1^*0502, DQB1^*0601 and DPB1^*0202 were found to be increased in the patients. These HLA alleles are in linkage disequilibria consisting of DRB1^*1602-DQB1^*0502 and DRB1^*0803-DQB1^*0601-DPB1^*0202 haplotypes. Since the frequencies of DRB1^*1401 and DRB1^*1502, that are in linkage disequilibria with DQB1^*0502 and DQB1^*0601, respectively, were not increased in the patients, the susceptibility to PBC was suggested to be controlled by the HLA-DRB1 locus. In contrast, the frequency of HLA-DQB1^*0302 was decreased in the patients, while the frequency of each DRB1 allele in linkage disequilibria with DQB1^*0302 did not differ significantly between the patient group and control group. This observation suggested that the resistance to PBC may be controlled by the HLA-DQ locus.