For instance, several HLA-DRB1 alleles have been associated with susceptibility to rheumatoid arthritis (RA) in different populations, HLA-DQA1 and HLA-DQB1 alleles have been strongly associated with type-1 diabetes and celiac disease, and specific HLA-DRB3*03:01 allele with Crohn’s disease (14, 15). This evidence concerns the gene HLA-DRB1 and rheumatoid arthritis.