In the present association study, we investigated the relevance of the classification of HLA-DRB1 alleles proposed by Tezenas du Montcel and colleagues [11] regarding susceptibility to RA, across various Caucasoid and non-Caucasoid population samples, using publicly available data from the 13th IHWG RA studies. The gene discussed is HLA-DRB1; the disease is rheumatoid arthritis.