396 - Oxidative and Nitrative Modifications of Blood Plasma Proteins in Patients with Myasthenia Gravis

Abstract

Myasthenia gravis (MG) is an autoimmune disease caused by production of antibodies against acetylocholine receptors of the neuromuscular junction (Ab). As oxidative damage is involved in inflammatory and autoimmune-mediated diseases, we studied oxidative modifications of blood plasma proteins in patients with MG. The group studied consisted of 50 MG patients, 24 with ocular and 26 with generalized MG (28 females and 22 males), mean age 66.7 (30-81) y, mean duration of disease 9.5 (0.5-34) y, mean level of Ab of 8.9 (0.1-85) nmol/ml, and 25 age-matched healthy controls. The patients were classified according to the type of MG (Osserman's classification), duration of disease ( 5 y) and Ab level (low, 3 nmol/l). Glycophore fluorescence was increased in ocular MG a . Dityrosine was increased in both types of MG c , in patients ill b and >5 c y, with low c and high c levels of Ab. N-formylkynurenine was increased in the ocular a and generalized b MG, in both disease duration groups a , in the group of low Ab a . Kynurenine was incre a sed in the group with high Ab a . Tryptophan fluorescence was decreased in ocular b and generalized a MG, in patients ill for b and >5 a y, with low a and high c A b . Thiol groups were decreased in ocular a and generalized c MG, in patients ill for >5 a y, in the group with high Ab a . AOPP was elevated in p a tients with high Ab a . Protein carbonyls were increased in both ocular b and generalized b MG, in patients ill for >5 b y, with low b and high b A b . FRAP and ABTS due to fast antioxidants were unchanged but ABTS due to slow antioxidants was lower in ocular c and generalized b MG, in patients ill for >5 c y, in patients with low c and high b A b ( a P b P c P