HLA-DMA alleles ave possible new markers of rheumatoid arthritis: Study ofa Corsican group

The HLA-DMA gene, along with the HLA-DMB gene, encodes the not classical cl ass II molecule. This molecule catalyzes the class-II-associated invariant- chain peptide (CLIP)antigen peptide exchange in classical class II molecule peptide-binding groove. As such, the DM heterodimer is an antigen presenta tion regulator and may be linked to immune system deficiencies such as thos e observed in autoimmune diseases. The study of DMA gene polymorphism seems be a reasonable approach to provide an answer to this question. Thanks to PCR-derived methods, the relationship between DMA gene polymorphism and rhe umatoid arthritis (RA) was demonstrated in the present study. The DMA*0101 allele was observed to confer a significant predisposition to RA while the DMA*0102 allele significantly protected from this disease. Polymorphism exp eriments with the HLA-DRB1 gene revealed that this relationship between DMA polymorphism and RA is not a consequence of a linkage disequilibrium with the HLA-DRB1 alleles implicated in this pathology. The;study of the DMA gen e could therefore prove to be very useful in the early diagnosis of RA. Cop yright (C) 1999 S. Karger AG, Basel.