In contrast to the significant increase in the serum IFN-γ and IL-4 levels in the CHB patients with fibrosis compared to the controls, the ratio of IFN-γ/IL-4 was significantly lower in the F5–6 group than in the F3–4 and F1–2 groups, respectively (P < 0.05), suggesting a negative correlation with the degree of fibrosis. The gene discussed is IL4; the disease is fibrosis.