Background
Rheumatoid arthritis (RA) is a chronic autoimmune disease that is characterized by inflammation of the synovial joints, which leads to joint destruction. Dendritic cells (DC) are specialized antigen presenting cells, which are activated by 'pathogen associated molecular patterns' via toll-like receptors (TLRs). TLR3 and TLR7 are important in the recognition of viral RNA, whereas TLR2 and TLR4 are involved in the recognition of bacterial components and host-derived molecules, including heat shock proteins, fibronectin, hyaluronic acid. TLR and DC are critical in the regulation of immune responses.