TNF and hepatitis A virus infection: The pathogenic importance of TNF-α in liver disease has been previously demonstrated: besides the increased concentration of TNF-α in the liver of patients with chronic hepatitis C [10], it has been observed that serum levels of this cytokine are correlated with histological grading score of hepatitis [11]; moreover, patients with increased serum levels of TNF-α or their receptors showed a reduced survival [12].