Erythrocytic glutathione in cystic fibrosis. A possible marker of pulmonary dysfunction.

To evaluate the role of red blood cell (RBC) antioxidants as clinical markers of oxidative exposure, we measured RBC glutathione (GSH) concentrations in 32 adult patients with cystic fibrosis (CF), and 8 healthy age-matched control subjects. We chose patients with CF because this disease is characterized by severe bronchial inflammation and marked oxidant-antioxidant imbalance. Although the GSH concentration of the two study groups was not significantly different, the RBC GSH concentration of patients with CF had a greater variability (p = 0.01) and was also inversely and significantly correlated to tests of pulmonary function (p < 0.05). These data indicate a large and significant interindividual variability of erythrocytic antioxidants in patients with CF, with a compensatory, but probably inadequate, increase in patients with more severe respiratory deterioration. Red blood cell GSH concentration may thus provide a biologic marker for disease severity and a rationale for antioxidant manipulation in these patients.