The factors affecting plasma glutathione peroxidase and selenium in rheumatoid arthritis: a multiple linear regression analysis.

The reactive oxygen radicals are trapped by anti-oxidants, such as selenium containing glutathione peroxidase (GSHpx), which also can inhibit the oxygenation of arachidonic acid to pro-inflammatory prostaglandins and leukotrienes. We studied the levels of anti-oxidant glutathione peroxidase and selenium (in plasma) in 48 patients with rheumatoid arthritis (RA). In the multiple regression model, joint score had the highest explanatory value for serum selenium, and sulphasalazine treatment was the most significant variable contributing to GSHpx activity. The plasma GSHpx activity was not increased in RA patients in general, but was high in those taking sulphasalazine as compared with those not doing so (342.4 +/- 48.2 vs. 298.9 +/- 34.7 U/l, 95% confidence interval of difference from 17.9 to 69.1, p less than 0.002). The serum selenium levels correlated with clinical activity of the joint, disease measuring joint score.