Selenium belongs to important essential minerals and its deficiency can cause serious clinical manifestations. Since we live in the region with selenium deficiency in food, the authors explored whether serum selenium concentration and activity of glutathione peroxidase in erythrocytes was affected in a group of patients with rheumatoid arthritis (RA). Concentration of selenium in serum and activity of glutathionperoxidase in erythrocytes were analyzed in 39 patients with RA and in 13 patients using selenium in a dose of 50 µg per day for a minimum of 4 months. Control group consisted of 21 healthy volunteers. Concentration of selenium in serum was measured by atomic absorption spectrophotometry and activity of glutathione peroxidase in erythrocytes by the commercial kit from RANDOX. The serum concentration of selenium in patients with rheumatoid arthritis was 0.95 ± 0.17 µmol/l and the activity of glutathione peroxidase was 62.21 ± 19.65 U/gHb. Concentration of selenium in patients using selenium was 1.53 ± 0.33 µmol/l and the activity of glutathione peroxidase was 66.86 ± 6.93 U/gHb. Mean of serum concentration of selenium in control group was 1.02 ± 0.18 µmol/l and the activity of glutathione peroxidase 52.57 ± 10.67 U/gHb. We have not found significantly different concentrations of serum selenium between patients with RA and control group (p=0.294). However, the activity of glutathione peroxidase was significantly higher in patients with RA than in the control group (p=0.033). Patients with RA using selenium had significantly higher serum levels of selenium compared to patients with RA not using selenium (p=0.012). But the activity of glutathione peroxidase in patients with RA using selenium was not significantly increased (p=0.381). Correlation of serum level of selenium and the activity of glutathione peroxidase was not found in any of the investigated groups.

        Key words: selenium, glutathione peroxidase, rheumatoid arthritis