HLA-B and rheumatoid arthritis: However, the few studies using imputation for determining the haplotypes on databases of patients with RA of Caucasian or Asian origin have converged on the finding that there is only an association with RA for HLA-A, specifically the asparagine residue at position 77 (HLA-A Asn77), and for HLA-B, the aspartic acid residue at position 9 (HLA-B*8-Asp9).