Prospective study of natural killer cell phenotype in recurrent hepatitis C virus infection following liver transplantation

Background/Aims: Graft re-infection invariably occurs after liver transplantation (OLT) for chronic hepatitis C and disease progression is unpredictable. We prospectively examined peripheral blood mononuclear cells (PBMC) subsets and natural killer (NK) cell receptors (NKRs) in patients with recurrent hepatitis C post-OLT. Methods: PBMC were obtained at baseline and at different time points after OLT. NKRs were identified using monoclonal antibodies by flow cytometry. Results: The proportions of NK, natural T (NT), total and gamma delta T cells were significantly reduced (p < 0.01) 7 days post-transplant, probably as a result of graft repopulation. NKG2D+ NK cells were significantly higher compared with healthy controls (p < 0.01), declined post-OLT and subsequently returned to baseline values. This, together with a progressive increase in the proportion of CD94/NKG2C+ NK cells over time (p <= 0.01), appeared to be related to hepatitis C recurrence. There was a statistically significant correlation between expression of the natural cytotoxicity receptors (NCRs) and ALT (p < 0.05), supporting the hypothesis that NK cells participate in the necroinflammatory process. Conclusions:The data are compatible with homing of immune cells to the liver allograft after surgery, most of which return to pre-OLT levels. HCV recurrence may cause variations in selected NKRs expression akin to other viral infections. (C) 2008 European Association for the Study of the Liver. Published by Elsevier BAI. All rights reserved. RI Fagnoni, Francesco/A-1642-2008