RA was firstly found to be significantly associated with HLA-DRB1 alleles carrying a common amino acid motif, which is the human leukocyte antigen (HLA)-DRB shared epitope (HLA-DRB-SE); however, the dosage of the shared epitope allele is only associated with patients who present aCCP antibodies [7]. Here, HLA-DRB1 is linked to rheumatoid arthritis.