HLA-DRB1 and rheumatoid arthritis: Similarly, O’Dell and colleagues demonstrated as early as 1998 that carriers of alleles, such as HLA-DRB1*04, HLA-DRB1*01, HLA-DRB1*10, and HLA-DRB1*14 in RA had a reduced likelihood of responding to first-line MTX therapy, specifically in achieving low disease activity (ACR 50).