Genetic polymorphism of HLA-DR in the Japanese population.

As a result of carrying out sequence analyses on the HLA-DR genes of several Japanese donors, we found three new DRB1 alleles, DRB1-12b, DRB1-14c, and DRB1-JX6, that had not been identified using immunological procedures. Sequence-specific oligonucleotide (SSO) probes directed against various DRB1 alleles, including the above three, enabled DNA typing of all the DRB types in the Japanese population and calculation of their gene frequencies based on this typing to be carried out for the first time. The SSO-DNA typing yielded higher DR13 and DR14 gene frequencies than those reported by serological workshops. Next, we applied this DR-DNA typing to the analysis of Japanese patients with juvenile rheumatoid arthritis (JRA) and found that DRB1*0405 was the allele susceptible to rheumatoid factor-positive polyarticular JRA, which is one of the four types of JRA that has been classified clinically. Analysis of the DR types of patients who suffered unexplained recurrent spontaneous abortion (URSA) using DNA typing demonstrated that 1) URSA is not correlated with any particular DR type and 2) no difference between the DR sharing rate of patients and normal couple was detected, which contradicts the results obtained in some serological studies.