ABSTRACT
Objective To assess the levels of glucose-6-phosphate isomerase(GPI) mRNA in peripheral blood monocytes and serum GPI levels in patients with rheumatoid arthritis, and analyze the association of serum GPI with MCV antibody, CCP antibody and RF of RA. Methods Fluorogenic quantitative real-time polymerase chain reaction (FQ-RT-PCR) was used to examine mRNA expression on peripheral blood monocytes in 60 RA patients (28 case in active stage,32 cases in stable stage) ,30 patients with other rheumatic diseases, and 30 healthy controls. ELISA was used to detect the levels of serum GPI, anti-MCV antibodies, anti-CCP antibodies and RF in each group. Results The levels of GPI mRNA in RA group [△Ct=4.21 (3.04-7.23)] were significantly higher than those in patients with other rheumatic diseases [△Ct=8.42 (5.16-9.98),P<0.01] and healthy controls [△Ct=8.66 (4.90-10.01), P<0.01]. There were statistically significant differences of GPI mRNA levels between active RA [△Ct=3.78 (1.28-6.09)] and inactive RA[△Ct =5.88(3.23-8.94),H=11.760,P<0.01)]. The RA group serum GPI levels [3.02 (2.02-8.39) mg/L] were higher than those of other rheumatic diseases [0.20 (0.11-0.32) mg/L] and healthy controls [0.18(0.08-0.30) mg/L]. There were significant differences of serum GPI levels between active RA group [4.84(2.81-10.38) mg/L] and inactive RA group[2.12 (1.26-4.34) mg/L] (H=9.830, P<0.01). The sensitivities of GPI, anti-MCV and anti-CCP were 68% (41/60) ,57% (34/60),58% (35/60), respectively and specificities were 95% (57/60), 92% (55/60) and 93% (56/60), respectively. Conclusions The high expression of GPI mRNA in RA patients shows that it may play a pathological role in the development of RA, and it may be correlated with the activity of RA. It may be a valuable diagnostic parameter for RA, because of its high sensitivity and specificity.