Immune response has a complex role in the recurrence of HCC following LT in patients with hepatitis C. After LT, our recent hepatic micro-RNA study revealed that, due to factors associated with cytochrome P450, which regulates immunosuppressive drugs in the liver, fluctuations in anti-HCV antibody levels may be the result of significant changes in CD4/CD8 T-cell activity in the immune system, which is essential for preventing organ rejection or attack on cholangiocytes. This evidence concerns the gene CD4 and hepatitis C virus infection.