Increased susceptibility to peroxide-induced haemolysis with normal vitamin E concentrations in cystic fibrosis.

Vitamin E status was assessed in 22 patients with cystic fibrosis and 9 controls by measuring concentrations of the vitamin, vitamin E:lipid ratios and peroxide-induced haemolysis in plasma and erythrocytes. For a given concentration of plasma or erythrocyte alpha-tocopherol, erythrocytes of patients with cystic fibrosis were more susceptible to peroxide-induced haemolysis than controls. This susceptibility should be countered by supplementation with vitamin E to maintain higher than normal concentrations of circulating alpha-tocopherol-greater than 4.8 mmol alpha-tocopherol/mol cholesterol.