HLA-DRB1 and rheumatoid arthritis: The shared epitope sequence is common in high-risk alleles for RA, such as HLA-DB1*01:01, HLA-DRB1*04:01, HLA-DRB1*04:04, HLA-DRB1*04:05, HLA-DRB1*14:02, and HLA-DRB1*10:01 [7,8,9].