HLA-DRB1 and rheumatoid arthritis: We analyzed these genetic markers (all currently known RA risk SNPs tagged by the Immunochip platform, and genome-wide SNPs) and several HLA-DRB1 amino acids (positions 11, 13, 71, and 74, and haplotypes defined by these positions), grouped into scores as well as individually, to evaluate how well they predict response to TNFi therapy among patients with RA who used TNFi as their first biological disease-modifying anti-rheumatic drug (bDMARD).