For instance, HLA-DRB1*04:01 and HLA-DRB1*04:04 alleles are common in RA patients with Caucasian ancestry, while HLA-DRB1*04:05 allele is common in the Asian population [3, 6, 7, 9, 12–15]. Here, HLA-DRB1 is linked to rheumatoid arthritis.