HLA-DRB1 and rheumatoid arthritis: Within a subset of RA patients, depending on the HLA-DRB1 SE allele, the most frequently represented HLA-ABC allele groups were HLA-C*07, HLA-A*02, and HLA-B*39.1, which were found to be most predominantly associated with the HLA-DRB1*14:02 allele.