Plasma concentrations of zinc, copper, interleukin-6 and interferon-γ, and plasma dipeptidyl peptidase IV activity in chronic hepatitis C

Copper and zinc are essential trace elements which play an important role in various biological processes. Along with various cytokines, glucocorticoids, glucagon and insulin, the acute-phase protein metallothionein is involved in the regulation of immune cell functions. Metallothionein is the central protein regulating zinc concentration. Zinc deficiency is often found in patients with chronic liver disease, chronic kidney disease and diabetes mellitus, and in those with acute infectious diseases. In contrast, copper deficiency is rarely reported. In order to determine whether there is a correlation between zinc and/or copper and selected immunological parameters in patients with chronic liver disease, we investigated plasma levels of zinc and copper, concentrations of interleukin-6 (IL-6) and interferon-γ (IFN-γ), and the enzymatic activity of dipeptidyl peptidase IV (DP IV, CD26) in patients with chronic hepatitis C and in healthy control subjects. Whereas zinc plasma levels did not differ between patients and control subjects, copper concentrations revealed gender-specific differences. The mean copper concentration was higher in female patients with chronic hepatitis C and in female controls compared with the respective male groups. The immunological parameters of IFN-γ concentration and DP IV activity showed similar levels in the patient and control groups. Of note, the mean IL-6 plasma concentrations were significantly elevated in patients with chronic hepatitis C compared with healthy control subjects. In summary, there was no correlation between either zinc or copper concentrations and the immunological parameters measured (IL-6 and IFN-γ levels and DP IV activity) in patients with chronic hepatitis C and in healthy control subjects.