Abstract: Objective　To investigate the significance of glucose-6 phosphate isomerase(G6PI) antigen level in the development of rheumatoid arthritis(RA).  Methods　The levels of G6PI antigen in 140 patients with RA，75 patients with other rheumatoid diseases and 50 healthy controls were determined by enzyme-linked immunsorbent assay (ELISA)．The levels of C reactive protein (CRP), rheumatoid factor (RF), erythrocyte-sedimentation rate (ESR), attic tenderness and engorge and X-ray′s classification were also assessed in RA patients.  Results　Serum G6PI antigen levels were (3.13±2.62)μg/mL in patients with RA，(0.148±0.045)μg/mL in patients with other rheumatoid diseases，and (0.107±0.065)μg/mL in healthy controls. The G6PI antigen level and positive rate in patients with RA were higher than those in patients with other rheumatoid diseases and healthy controls (P＜0.01). The G6PI antigen level and positive rate in active RA group were higher than those in inactive RA group (P＜0.05)，and serum G6PI antigen level was positively correlated with CRP and the attic tenderness and engorge of RA.  Conclusions　The G6PI antigen acts as a potential contributor in the development of RA, and may become a useful diagnostic marker for RA and an indicator for therapeutic effect.

Key words: Glucose-6 phosphate isomerase, Rheumatoid arthritis, Enzyme-linked immunosorbent assay