HLA-DRB1 and rheumatoid arthritis: We did find a high frequency of DRB1*03:01:01:01 (11.76% in elderly women and 6.12% in elderly men), and it is known that the DRB1*03:01 allele is considered a protective allele for rheumatoid arthritis, but also a susceptible allele for type 1 diabetes or HIV progression to AIDS; however, with these studies being low-resolution, we do not know what impact and role each allele has.