HLA-DRB1 and rheumatoid arthritis: [73] additionally demonstrated that microbial genes from Clostridium, Eggerthella, Bacteroides, and Citrobacter in RA patients display molecular mimicry with RA-associated antigens, including collagen XI and HLA-DRB1*0401, and many genes belonging to metagenomic junction group were enriched in RA intestinal samples.