Subclinical reduced G6PD activity in rheumatoid arthritis and Sjogren's Syndrome patients: Relation to clinical characteristics, disease activity and metabolic syndrome

Objective. Glucose-6-phosphate dehydrogenase (G6PD) is an important site of metabolic control in the pentose phosphate pathway. The purpose of this study was to investigate the enzyme activity of G6PD in Rheumatoid Arthritis (RA) and Sjogren's Syndrome (SS) patients not known to be deficient in this enzyme. It was also within the scope of the aim to find the relation of G6PD to the presence of metabolic syndrome (MetS) in these patients. Methods. Erythrocyte G6PD activity was evaluated in 40 RA patients, 30 SS patients and in 30 age- and sex-matched control. The clinical characteristics, disease activity score (DAS28), SS disease activity (SSDAI) and damage (SSDDI) indices and presence of MetS of the included patients were analyzed in relation to the enzyme level. Results. The G6PD activity in RA patients (7.72 +/- 3.57 U/g Hb) was significantly reduced compared to that in the SS patients (11.55 +/- 3.14 U/g Hb) and control (13.23 +/- 3.34 U/g Hb) especially those with MetS (4.61 +/- 1.84 U/g Hb) (p < 0.001). There was a significant negative correlation of the G6PD activity with the disease duration and DAS28 (p < 0.001). Conclusion. The results of this study, suggest that G6PD not only does not protect against MetS in RA, but may even be considered a risk factor for the development of this disorder. The identification of regulatory tools for G6PD activity may prove promising for treating the associated metabolic disorders and chronic inflammation in RA.