The human MxA
protein is a new specific marker for
type I interferon activity both in vitro and in vivo. In the study presented here, this
interferon-induced marker, as well as the
2',5'-oligoadenylate synthetases, was measured in circulating mononuclear cells from 21 patients with acute
hepatitis A, 20 patients with acute
hepatitis B and 14 patients with acute
hepatitis C for determination of the activation of the
interferon system in these
viral diseases. In acute
hepatitis A a strong expression (10 of 10 patients) of the MxA
protein and the
2',5'-oligoadenylate synthetase activity in peripheral-blood mononuclear cells was observed during the first 2 wk after onset of clinical symptoms. In this period the MxA
protein concentrations reached levels similar to those measured in patients treated with up to 5 x 10(6) IU
interferon-alpha three times a week. Beyond wk 3, in eight of eight patients with
hepatitis A no increased MxA
protein levels were found. In contrast, peripheral-blood mononuclear cells from patients with acute
hepatitis B contained either no measurable MxA
protein or only slightly higher levels of the MxA
protein, as did those of most patients (12 of 14) with acute
hepatitis C. The MxA
protein levels of both
hepatitis B and C patients were significantly lower (p < 0.05) than those found in
hepatitis A patients. Furthermore, sera from 6 of 10 patients with
hepatitis A, but none of 10 patients with acute
hepatitis B and C, contained measurable MxA
protein. This serum MxA
protein may originate from
interferon-exposed and subsequently damaged liver cells.(ABSTRACT TRUNCATED AT 250 WORDS)