Effect of alpha-interferon on natural killer cell activity and lymphocyte subsets in thalassemia patients with chronic hepatitis C.

The variation of natural killer (NK) cell activity and lymphocyte subsets 20 h after a single test dose of alpha-IFN, was studied in 17 thalassemic patients with chronic hepatitis C. All patients had suspended the alpha-IFN therapy at least 12 months before the study: 10 were considered responders and 7 nonresponders. Also NK cell cytotoxicity after in vitro incubation with alpha-IFN was studied. The administration of a single dose of alpha-IFN increased NK cell cytotoxic activity significantly in the group of responders and in non-responders; moreover the NK cell cytotoxic activity after alpha-IFN in vitro incubation increased both in responders and nonresponders, but to a lesser degree than in healthy controls. Absolute values of CD4+ and CD8+ lymphocytes decreased significantly only in responders. In conclusion, our data suggest that the variation of NK cytotoxic activity and lymphocyte subsets after a test dose of alpha-IFN can be considered a parameter related to IFN biological effects.