Dynamic interactions between T cells and dendritic cells and their derived cytokines/chemokines in the rheumatoid synovium.

This review focuses on the contributions made by interactions between dendritic cells (DCs) and T cells, and by local production of cytokines and chemokines to the pathogenesis of rheumatoid arthritis (RA) synovitis. DCs are efficient professional antigen-presenting cells, which are critical for the development of innate and adaptative immune responses through interactions with T cells. Cytokines from DCs play a key role in the switch inside effector T-cell pathways. Chemokines are important mediators of the immune response because they regulate leucocyte recruitment to tissue, and they play a key role in inflammatory diseases by acting on T-cell and DC migration. Furthermore, the recently discovered T-helper-17 proinflammatory cytokines, present in syno-vium samples, are associated with the migration, differentiation and maturation of inflammatory cells, and they facilitate a network of interactions between all components of the immune response. An understanding of such interactions is essential because it is the key to therapeutic application.