Effects of ascorbic acid on neutrophil function. Studies on normal and chronic granulomatous disease neutrophils

Ascorbic acid is able to stimulate neutrophil oxidative metabolism in normal neutrophils, as well as other several functions of these cells, either in the normal state or in the defective one. In the present study, we have investigated the effects of ascorbic acid on the hexose monophosphate shunt (HMPS) and on the bactericidal activity of neutrophils from Chronic Granulomatous Disease (CGD) patients. Furthermore, we have investigated the effects of ascorbic acid on the antibody dependent cell cytotoxicity (ADCC) of normal neutrophils. Ascorbic acid in vitro was able to significantly improve both HMPS activity and bacterial killing of CGD neutrophils. Its prolonged administration to such patients led to consistent clinical improvement, possibly related to the enhancement of chemotaxis, although the effects on HMPS and bacterial killing seen in vitro could not be confirmed. Ascorbic acid was also able to interfere with neutrophil ADCC with different results depending on its concentration and the experimental conditions.