Objective To investigate the expressions and significances of Th1/Th2 cytokines in the peripheral blood (PB) and synovial fluid (SF) of patients with rheumatoid arthritis (RA). Methods Totally 15 PB samples and 36 knee joint SF were collected from 41 RA patients who diagnosed for the first time in our department from January 2006 to December 2007. They all were diagnosed as RA according to the diagnostic criteria of American College of Rheumatology (ACR) and received no any immunosuppressive treatment. Another 5 samples from health individuals served as normal control. Expressions of IL-2

IL-4

IL-6

IL-10

TNF-α and IFN-γ were examined by cytometric bead array (CBA). Serum expression of cyclic citrullinated peptide (CCP) was measured by ELISA. Results Expressions of IL-2(6.32±0.34 pg/ml)

IL-4 (5.83±0.30 pg/ml)

IFN-γ (18.62±11.52 pg/ml)

IL-6 (6 217.78±4 336.18 pg/ml) and IL-10 (35.28±8.02 pg/ml) were significantly increased in the SF of RA patients (P0.01). Expression of IFN-γ (18.62±11.52 pg/ml) was significantly increased in PB of RA patients (P0.01). Expression of TNF-α was increased in SF (17.34±4.78 pg/ml) and PB (29.48±14.26 pg/ml) of RA patients (P0.05). Furthermore

ratio of IFN-γ/IL-4 (3.34±0.42) was significantly increased in SF than in PB of RA and healthy donor (P0.01).  Moreover

compared with CCP-negative patients

the expressions of IL-2 (5.41±1.37 pg/ml) and IL-6 (5 360.21±3 705.78 pg/ml) were increased (P0.05)

and the expressions of TNF-α (15.99±3.75 pg/ml) and IFN-γ (29.04±12.46 pg/ml) were very significantly increased in CCP-positive patients (P0.01). Conclusion Altered polarization of Th1/Th2 is the principal mechanism of immunopathogenesis in RA. In topical part of arthritis

Th1 polarization induces the inflammation. Furthermore

inflammation of arthritis may be more severe in CCP-positive RA patients than negative ones.