ELEVATED SERUM LEVELS OF MANGANESE SUPEROXIDE-DISMUTASE IN POLYMYOSITIS AND DERMATOMYOSITIS

We studied serum concentrations of manganese superoxide dismutase (Mn SOD) and copper-zinc superoxide dismutase (Cu/Zn SOD) in 22 patients w ith polymyositis and dermatomyositis (PM/DM), 87 patients with four ty pes of muscular dystrophy, 20 patients with amyotrophic lateral sclero sis, and 15 patients with collagen vascular diseases (CVD). Serum leve ls of Mn SOD were increased only in the patients with PM/DM and CVD, a nd the elevation was more prominent in those with PM/DM. Levels of Cu/ Zn SOD were slightly elevated in some patients with PM/DM and Duchenne muscular dystrophy. In patients with PM/DM, the change in Mn SOD leve ls corresponded to disease activity as closely as or more closely than those of creatine kinase. The results indicate that serum Mn SOD may be a useful clinical marker for PM/DM.