TY - JOUR T1 - Altered natural killer cell subset distributions in resolved and persistent hepatitis C virus infection following single source exposure JF - Gut JO - Gut DO - 10.1136/gut.2007.130963 AU - Lucy Golden-Mason AU - Laura Madrigal-Estebas AU - Emma McGrath AU - Melissa J Conroy AU - Elizabeth J Ryan AU - John E Hegarty AU - Cliona O'Farrelly AU - Derek G Doherty Y1 - 2008/03/27 UR - http://gut.bmj.com/content/early/2008/03/27/gut.2007.130963.abstract N2 - Background: Natural killer (NK) cells may be impaired in patients with persistent hepatitis C virus (HCV) infection, but studies to date have yielded inconsistent findings due to patient and virus heterogeneity and difficulties obtaining appropriate controls. Aims: To overcome these variables, we have examined numbers, phenotypes, cytotoxic activities and cytokine profiles of circulating NK cells from Irish females who acquired infection through administration of HCV genotype 1b-contaminated anti-D immunoglobulin from a single source and matched controls. Results: Comparing 29 women who developed persistent infection with 21 who spontaneously resolved infection and 26 controls, we found that NK cell numbers were consistently lower in the persistently-infected group (p=0.02 and 0.002). This decrease was due to depletions of NK cells expressing low levels of CD56 (CD56dim NK cells; p=0.004 and 0.0001), whilst CD56bright NK cells were expanded (p=0.004 and 0.0001). Compared to HCV resolvers, CD56dim NK cells from persistently-infected patients less frequently expressed CD16 and more frequently expressed NKG2A/C/E. These phenotypic changes did not significantly affect natural or interleukin-2-induced cytotoxicity by peripheral blood mononuclear cells against K562 and Daudi targets. Greater frequencies of CD56bright NK cells from chronic HCV patients produced interferon-γ compared to HCV responders (p=0.05) and controls (p=0.0001) after phorbol ester stimulation in vitro. Conclusions: Alterations in NK subset distributions in chronic HCV infection may explain why previous reports of impaired NK cell functions were difficult to confirm. Altered NK cell functions may contribute to impaired cellular immune responses and chronicity of disease following HCV infection. ER -