HLA-DRB1 and rheumatoid arthritis: Taking EBV infection in RA as an example (Figure 3), molecular mimicry occurs between EBV and self-proteins such as: Epstein–Barr nuclear antigen 1 (EBNA1) and human cytokeratin; a sequence in the gp110 EBV glycoprotein and sequence QKRAA located in HLA-DRB1*0401, a susceptibility factor for RA [197].