Objective:To explore the role and significance of IL-17 on the pathogenesis of rheumatoid arthritis ( RA).Methods:The levels of IL-17 mRNA in peripheral blood mononuclear cell ( PBMC) of 66 RA patients (32 active,34 inactive) and 44 healthy controls were detected by reverse transcription-polymerase chain reaction ( RT-PCR ).The levels of serum IL-17 were detected by enzyme-linked immunosorbent assay ( ELISA).The levels of RF were detected by immunoturbidimetric assay.The correlations of serum IL-17 and RF were analyzed.Results: In RA patients the levels of IL-17 mRNA in PBMC were significantly higher than those in healthy controls ( P＜0.05 ) , but there was no difference between the active and inactive RA ( P>0.05 ).The serum IL-17 levels in active RA patients were significantly higher than those in inactive RA patients and healthy controls ( P＜0.05 ).The levels of serum IL-17 were positively correlated with RF in RA patients.Conclusion: IL-17 and RF play an important role in the pathogenesis and pathology process of RA ,and IL-17 may be associated with RA activity.