Positive and negative association of HLA-DR genotypes with Japanese rheumatoid arthritis.

OBJECTIVE

To clarify the relationship between the HLA-DR genotype and susceptibility to rheumatoid arthritis (RA) in Japanese patients.

METHODS

HLA-DR typing and DRB1* genotyping were carried out by PCR and PCR-SSCP (single stranded DNA conformation polymorphism), respectively.

RESULTS

In RA, the prevalence of HLA-DR4 was significantly higher (57.3%, p < 0.05). In particular, DRB10405 was predominantly higher (46.9%, p < 0.05) and DRB10401 was also increased although not significantly. HLA-DR8, especially DRB10802, was significantly lower (1.0%, p < 0.01). RA patients homozygous for DRB10405 showed slightly higher values for the erythrocyte sedimentation rate, gamma-globulin, and IgG, as well as positivity for rheumatoid factor and high titers for the Waalar-Rose test, and a decrease in the albumin/globulin ratio, albumin, and hemoglobin in comparison to patients without RA susceptibility genes, although the difference for each of these parameters was not significant.

CONCLUSION

DRB10405 and DRB10802, which are both rare alleles in Caucasians, are positively and negatively correlated, respectively, with the pathogenesis of RA in Japan.