Reduced plasma transforming growth factor-β1 levels in patients with chronic hepatitis C after interferon-α therapy: association with regression of hepatic fibrosis

Background/Aim: Transforming growth factor-β1 is involved in liver fibrosis. Our aim was to examine the association of plasma transforming growth factor-β1 levels with the degree of liver fibrosis. Methods: We analyzed plasma transforming growth factor-β1 levels in 43 patients with chronic hepatitis C treated with interferon-α using a transforming growth factor-β1 ELISA. The content of transforming growth factor-β1 in liver tissue obtained by needle biopsy (n=13) was also analyzed. The degree of liver fibrosis was assessed histologically and morphometrically. Results: Plasma transforming growth factor-β1 levels were significantly correlated with transforming growth factor-β1 content in liver tissue (r=0.83,p<0.001), indicating that plasma levels correspond with tissue cytokine. Plasma transforming growth factor-β1 levels in patients (8.1±1.1 ng/ml) before interferon-α therapy were significantly higher than in controls (1.9±0.3 ng/ml) (p<0.01). Plasma levels were significantly correlated with the degree of fibrosis (p<0.01). Plasma transforming growth factor-β1 levels were significantly decreased in sustained responders (from 5.2±1.0 ng/ml to 2.9±0.7 ng/ml), relapsed patients (from 9.8±2.0 ng/ml to 3.4±0.6 ng/ml), and nonresponders (from 9.3±2.1 ng/ml to 3.9±0.9 ng/ml) at the end of therapy (p<0.05 for all comparisons). Significant regression of liver fibrosis after therapy was observed in both sustained responders and nonresponders (p<0.05 for both). Conclusions: These observations suggest that plasma transforming growth factor-β1 levels appear to be associated with the degree of liver fibrosis.