Cytokines carry out many crucial biological processes like cell growth, proliferation, differentiation, inflammation, tissue repair and regulation of the immune response [9] [10]. It is well known that they play an important role in the pathogenesis of RA and are responsible for inflammation and joint destruction that occur during arthritis [11]. There occurs an imbalance between the pro- and anti-inflammatory cytokine activities which leads to multi-system immune complications [9].

The inflammatory milieu in the synovial compartment is regulated by a complex cytokine network. It is believed that B cells, T cells and over-production of various pro-inflammatory cytokines and de-regulation of anti-inflammatory cytokines regulate the pathophysiology of RA. Clinical interventions clearly demonstrate that of these components, tumour necrosis factor (TNF), interleukin 6 (IL-6), and probably granulocyte-monocyte colony stimulating factor are essential to the process. Cytokines lead to the induction or aggravation of the inflammatory response by activating endothelial cells and attracting immune cells to accumulate within the synovial compartment [3].

Although immune system which is regulated by cytokine network is complex, many of cytokines such as TNF-α, IL-6, IL-17 have been tested as therapeutic targets with notable success in RA and subsequently other inflammatory diseases, whereas targeting of other cytokines rendered low or no therapeutic success [3].

In conclusion, it is important to recovery balance of cytokine network and to improve immune function [12].