Ten additional peptides produced a very weak proliferative response and the GRP78/BiP456–475 peptide (DNQPTVTIKVYEGERPLTKD) was identified as an IL‐10‐inducing epitope in RA patients and healthy donors, that could be blocked by anti‐HLA blocking antibodies, suggesting T‐cell receptor interaction with the BiP peptide containing HLA molecule was essential for IL‐10 production. Here, HSPA5 is linked to rheumatoid arthritis.