HSPA5 and rheumatoid arthritis: MycHSP70 and BiP shared 50% amino acid sequence similarity and MycHSP70287–306 located at the corresponding position of the major epitope for human BiP, BiP336–355 (RSTMKPVQKVLEDSDLKKSD), which we previously identified as a RA-related HLA-DR4 effector epitope (Fig. 3B)8.