Antioxidant enzymes in red blood cells and lymphocytes of ataxia-telangiectasia patients.

Toxic oxygen metabolites may contribute to the development of tissue damage, and play a role in the pathogenesis of malignancies, some acute and chronic pulmonary diseases, and in cell damage by radiomimetic agents, which can be seen in patients with ataxia-telangiectasia (A-T). Oxidative stress resulting from increased free radical production and/or defects in antioxidant defences is also involved in neurodegenerative disorders. Thus, oxidative stress could account for several aspects of the pleiotropic phenotype of A-T patients. The aim of this study was to determine the activities of the enzymes involved in cellular antioxidant metabolism in A-T patients to see if there is any defect which may result in constant oxidative stress. Superoxide dismutase (SOD) and catalase activities of erythrocytes, in contrast to lymphocytes, were found to be significantly higher in patients than in healthy controls. Our results may be another indication for the presence of constant oxidative stress in A-T patients as suggested previously.