The association of HLA-DM genes with rheumatoid arthritis in eastern France

In this study, the polymorphisms of the HLA DMA and DMB genes in patients w ith rheumatoid arthritis (RA) were examined. DMA and DMB typing was performed in 120 white RA patients from eastern Fran ce and 100 healthy controls, using PCR-SSO (sequence specific oligonucleoti de probes) method for DMA determination and PCR-RI;LP (restriction fragment : length polymorphism) method for DMB typing. All patients and controls had been HLA DRB1* genotyped. DMA*0103 was found significantly increased in RA patients (RA vs, controls: 18.3% vs. 4%) (p(corr) = 0.004; OR: 5.39; CI: 1.67-19.23). A decreased fre quency of DMA*0102 was also observed in the RA group (RA vs. controls: 18.3 % vs. 31%), bur not significantly. There were no differences in the prevale nce of DMB alleles between RA and controls. The patients and the controls w ere then stratified according to the expression of the HLA DRB1* RA-linked alleles (DRB1*01 and *04) and this allowed us to find no linkage disequilib rium between DMA*0103 and DRB1*01 or *04 alleles. Finally, most DMA*0103 pa tients were positive for rheumatoid factors and had extraarticular involvem ent such as subcutaneous nodules. Thus, our results suggest that DMA*0103 could be an additional genetic fact or for RA susceptibility in French whites. (C) American Society for Histoco mpatibility and Immunogenetics, 2000. Published by Elsevier Science Inc.