Aim: An abnormal fatty acid pattern in advanced liver cirrhotic (LC) patients has been reported in plasma phospholipids and some other tissues. We elucidated the significance of arachidonic acid deficiency on clinical pathophysiology of LC and hepatocellular carcinoma (HCC). Methods: We analyzed fatty, acid composition in mononuclear cell phospholipids, plasma α-tocopherol and tiobarbituric acid reactive substances (TBARS), and serum cytokines on 23 hepatitis C virus (HCV) infected cirrhotic patients, 12 without HCC and 11 with HCC. Results: Significantly low levels of n-6 polyunsaturated fatty acid, linoleic (LA), eicosadienoic, dihomo-γ-linolenic and arachidonic acid (AA) in LC patients were observed compared with control subjects. The plasma α-tocopherol level was lower and TBARS was higher in HCC patients than that in control subjects. AA/LA molar ratio in mononuclear cell phospholipids was correlated significantly with lymphocyte and platelet count in the cirrhotic patients. The serum IL-12 level tended to correlate with the AA/LA ratio. Conclusions: These results suggest that n-6 fatty acid composition in mononuclear cells may have an important roll in progression of HCV cirrhosis. Nutritional management preventing fatty acid peroxidation and maintaining AA and other polyunsaturated fatty acid levels may have some beneficial effects on the progression of HCV chronic liver disease. [ABSTRACT FROM AUTHOR]