Lack of evidence for the Th2 predominance in patients with chronic hepatitis C

Abstract

A T helper (Th)1 to Th2 shift has been proposed to be a critical pathogenic determinant in chronic hepatitis C. Here, we evaluated mitogen-induced and hepatitis C virus (HCV) core antigen-induced cytokine production in 28 patients with biopsy-proven chronic hepatitis C. Flow cytometry demonstrated that after mitogenic stimulation the percentage of Th2 cells (IL-4 + or IL-13 +) and Th0 cells (IFN-gamma/IL-4 + or IL-2/IL-13 +) did not differ between patients and controls. In contrast, the percentage of Th1 cells (IFN-gamma + or IL-2 +) was significantly increased in CD4 +, CD8 +, 'naive'-CD45RA + and 'memory'-CD45RO + T-cell subsets from patients versus controls. Similar results were obtained by ELISA testing supernatants from mitogen-stimulated, unfractionated peripheral blood mononuclear cell (PBMC) cultures. Interferon-alpha treatment was associated with a reduction in the mitogen-induced Th1 cytokine response in those patients who cleared their plasma HCV-RNA. Analysis of cytokine expression by CD4 + T cells after HCV core antigen stimulation in a subgroup of 13 chronic hepatitis C patients demonstrated no cytokine response in 74% of these patients and an IFN-gamma-restricted response in 26%. Finally, no Th2 shift was found in lipopolysaccharide-stimulated monocytes. These data indicate that a Th1 to Th2 shift does not occur in chronic hepatitis C.

Fig. 1

Detection of T-helper (Th)-1, Th2 and Th0 cells by cytofluorimetric analysis. Mitogen-stimulated PBMC were stained as described in the legend to Table 2 and analysed on FL1 (FITC) versus FL2 (PE) two-dimensional plots to discriminate positive cells. (a, c) PBMC from a typical control subject. (b, d) PBMC from a typical patient. Left lower quadrants: unstained cells. Left upper quadrants: Th1 cells staining positive exclusively for FITC-anti-IFN-γ or anti-IL-2 monoclonal antibodies. Lower right quadrants: Th2 cells staining positive exclusively for PE-anti-IL-4 and anti-IL-13 monoclonal antibodies. Right upper quadrants: Th0 cells staining simultaneously for anti-IFN-γ plus anti-IL4 or anti-IL-2 plus anti-IL-13 monoclonal antibodies.

Fig. 2

Cytokine measurement of mitogen-induced cytokine production by ELISA testing of supernatants from unfractionated peripheral blood mononuclear cells. a, IL-4; b, IL-10; c, IL-13; d, IFN-γ; e, IL-2.Bars represent S.D.

Fig. 3

Cytokine expression by in vitro activated T lymphocytes from HCV patients before (□) and after four months (▪) of IFN-α therapy. Mitogen-stimulated PBMC were stained as described in the legend to Table 2 and analysed by FACS. Bars represent S.D.