AIM:To evaluate the efficacy of granulocyte colony stimulating factors(G-CSF)in liver transplanted patients with hepatitis C(HCV)recurrence and Pegylated-IFN α-2b induced neutropenia,and to evaluate the impact of G-CSF administration on virological response. METHODS:Sixty-eight patients undergoing antiviral treatment for post-liver transplantation(OLT)HCV recurrence were enrolled.All patients developing neutropenia received G-CSF. RESULTS:Twenty three(34%)received G-CSF.Mean neutrophil count at the onset of neutropenia was 700/mmc(range 400-750/mmc);after 1 mo of G-CSF it increased to 1210/mmc(range 300-5590/mmc) (P<0.0001).Three patients did not respond to G-CSF. Treatment duration was similar in neutropenic and non-neutropenic patients.No differences in the rate of discontinuation,infections or virological response were observed between the two groups.G-CSF was protective for the onset of de novo autoimmune hepatitis(P<0.003). CONCLUSION:G-CSF administration is effective in the case of Peg-IFN induced neutropenia increasingneutrophil count,prolonging treatment and leading to sustained virological response(SVR)rates comparable to non-neutropenic patients.It prevents the occurrence of de novo autoimmune hepatitis. AIM: To evaluate the efficacy of granulocyte colony stimulating factors (G-CSF) in liver transplanted patients with hepatitis C (HCV) recurrence and Pegylated-IFN α-2b induced neutropenia, and to evaluate the impact of G-CSF administration on virological response METHODS: Sixty-eight patients undergoing antiviral treatment for post-liver transplantation (OLT) HCV recurrence were enrolled. All patients developed neutropenia received G-CSF. RESULTS: Twenty three (34% onset of neutropenia was 700 / mmc (range 400-750 / mmc); after 1 mo of G-CSF it increased to 1210 / mmc (range 300-5590 / mmc) -No differences in the rate of discontinuation, infections or virological responses were observed between the two groups. G-CSF was protective for the onset of de novo autoimmune hepatitis (P < 0.003). CONCLUSION: G-CSF administration is effective in the case of Peg-IFN induced neutropenia increasing neutrophil count, prolonging treatment and leading to sustained virological response (SVR) rates comparable to non-neutropenic patients. It prevents the occurrence of de novo autoimmune hepatitis.