Could HLA-DRB1 be the protective locus in rheumatoid arthritis?

Extensive studies in different ethnic groups have associated the susceptibility to development of rheumatoid arthritis (RA) with the third hypervariable region of the major histocompatibility complex (MHC) HLA-DR beta 1 molecule. On the basis of recent findings in the experimental mouse model of collagen-induced arthritis, Eric Zanelli, Miguel Gonzalez-Gay and Chella David propose that the HLA-DRB1 locus is associated with protection to RA and that the actual arthritogenic peptide-presenting molecule is HLA-DQ. Thus, the development of RA would depend upon the expression of the susceptible DQ allele and the nonprotective DRB1 alleles, along with environmental factors that trigger the autoimmune process.