In the present work, we investigated the expression of GRP78 of plasma cells in both synovial tissue and fluid in inflamed peripheral joints of RA, trying to explore the expressional profiles of GRP78 of plasma cells in distinct histological variants of rheumatoid synovitis and thus to determine whether there was a potential link between activation of the UPR of plasma cells and ectopic lymphoid neogenesis in rheumatoid synovium as well as the local production of pathogenic autoantibody such as anti-CCP. The gene discussed is HSPA5; the disease is rheumatoid arthritis.