HLA-DRB1 and rheumatoid arthritis: Regarding the association between HLA and the efficacy of bDMARDs, a study reported a significant improvement in disease activity with TNF inhibitors when the amino acids at positions 11, 71, and 74 of HLA-DRB1 were valine, lysine, and alanine, respectively, using RA cohort data from the United Kingdom7.