The aim of this study was to evaluate the effect of pegylated interferon-alpha (PEG-IFN-α) on the plasma citrulline/arginine ratio, regarded as an index of nitric oxide (NO) synthesis, in patients with high-risk melanoma. Forty patients were randomly assigned to either PEG-IFN-α treatment (n = 22) or to observation only (control group, n = 18). The treatment group received 6 μg PEG-IFN-α/kg once a week during 8 weeks, followed by a maintenance dose of 3 μg/kg/wk. Blood was collected at different time points, plasma concentrations of citrulline and arginine were measured and the ratio of citrulline/arginine was calculated. Patients treated with PEG-IFN-α showed a significant decrease in the concentrations of citrulline and in the citrulline/arginine ratio during the whole study period, both compared to baseline values and to the control group. The data suggest that therapy with PEG-IFN-α results in a marked decrease in the synthesis of NO in melanoma patients.

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Amino Acids
Erasmus MC: University Medical Center Rotterdam

Fekkes, D., Bannink, M., Kruit, W., van Gool, A., Mulder, P., Sleijfer, S., … Stoter, G. (2007). Influence of pegylated interferon-α therapy on plasma levels of citrulline and arginine in melanoma patients. In Amino Acids (Vol. 32, pp. 121–126). doi:10.1007/s00726-006-0284-3