Establishment and characterization of nurse cell-like stromal cell lines from synovial tissues of patients with rheumatoid arthritis

Objective. To investigate the features of synovial stromal cells establishe d from patients with rheumatoid arthritis (RA), and to define these cells a s nurse cells. Methods. Synovial nurse-like stromal cell lines (RA-SNCs) were established from patients with RA. These cell lines were examined for morphology, pseud oemperipolesis activity, cell surface markers, and cytokine production. The interaction between these RA-SNCs and a synovial tissue B cell clone was a lso examined. Results. RA-SNCs had nurse cell activity. They spontaneously produced inter leukin-6 (IL-6), IL-8, granulocyte colony-stimulating factor, and granulocy te-macrophage colony-stimulating factor. Furthermore, they produced IL-1 be ta and tumor necrosis factor alpha and expressed higher levels of the other cytokines after coculture with the B cell clone. Proliferation and Ig prod uction by the B cell clone were dependent on direct contact with RA-SNCs. Conclusion. These results indicate that the RA-SNCs were nurse cells, The f indings suggest that RA-SNCs may play an important role in the pathogenesis of RA by producing large amounts of cytokines and maintaining infiltrating lymphocytes.