ABSTRACT
Objective To investigate the diagnostic value of gluocose-6-phosphate isomerase (G6PI) detected by an enzy-me linked immunosorbent assay (ELISA) in patients with rheumatoid arthritis (RA). Methods The G6PI was detected by ELISA in serum samples from 106 patients with RA, 53 non-RA controls with various rheumatic diseases, and healthy individuals. The level of rheumatoid factor (RF), anti-CCP antibodies and AKA were also assessed in RA patients. The correlation analysis beween G6PI and anti-CCP, IgM-RF. G6PI, anti-CCP, IgM-RF and AKA were carried out between patients with erosion and with non-erosion diseases . Results ① G6PI serum level of patients with RA was (1.61 ±1.20) μg/ml, and was (0.11 ±0.17) in patients with other rheumatic diseases, and (0.06±0.07) μg/ml in healthy individuals. There was statistical significant difference between RA patients and patients with other rheumatic diseases (P<0.05). Receiver operator curve analysis (ROC) showed an opitium cut off level for C6PI at 0.225 μl/ml. The sensitivity of G6PI was 0.868, the specificity was 0.853 in RA. C6PI was associated with RF, but was not associated with anti -CCP. C6PI ws not associated with disease activity index by Spearman' s correlation analysis. The association between above parameters with bone erosion was not detected, however. Conclusion C6PI is abnormally increased in some RA so it may be a new diagnostic marker for RA. G6PI has a reasonable sensitivity (86.8%) and with high specificity(85.3%) to RA and it is valuable for RA diagnosis. C6PI is associated with RF, but not completely overlaps. C6PI is not associated with diseases activity. No association is found between G6PI and bone erosions.