Serum nitrotyrosine levels in patients with multiple sclerosis: relationship with clinical activity

Abstract

We have assayed levels of nitrotyrosine, one of the products of peroxynitrate (ONOO-), in the sera of 20 controls and 14 patients with multiple sclerosis (MS). These were in different stages of clinical activity: seven with clinical remission (RR) (clinically inactive) and seven with chronic progressive (CP) disease (four active and three inactive). The Ievels of nitrotyrosine were significantly higher (P < 0.0001) in MS patients (112.79 ± 33.24 ng/ml) than in the controls (20 .0 ± 8.0 ng/ml). The highest increase (155.6 ± 18.3 ng/ml) was in active chronic progressors (PCA) and these values were significantly higher than in RR patients (91.7 ± 25. 7 ng/ml, P < 0.0001) and inactive CP (117.5 ± 9.2 ng/ml, P < 0.05) patients, Serum nitrotyrosine levels are raised considerably in MS patients and they may vary with the stage and activity of the disease. Future studies should ascertain the importance of serum peroxynitrate formation in MS.