Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jun 21, 2012; 18(23): 2887-2894
Published online Jun 21, 2012. doi: 10.3748/wjg.v18.i23.2887
New perspectives in occult hepatitis C virus infection
Vicente Carreño, Javier Bartolomé, Inmaculada Castillo, Juan Antonio Quiroga
Vicente Carreño, Javier Bartolomé, Inmaculada Castillo, Juan Antonio Quiroga, Foundation for the Study of Viral Hepatitis, C/Guzmán el Bueno 72, 28015 Madrid, Spain
Author contributions: Carreño V, Bartolomé J, Castillo I and Quiroga JA equally contributed to generating the ideas for this review and writing this manuscript.
Supported by Fundación de Investigaciones Biomédicas (Madrid, Spain); and the Fundación Mutua Madrileña (Madrid, Spain)
Correspondence to: Vicente Carreño, MD, PhD, Foundation for the Study of Viral Hepatitis, C/Guzmán el Bueno 72, 28015 Madrid, Spain. fehvhpa@fehv.org
Telephone: +34-91-5446013 Fax: +34-91-5449228
Received: August 5, 2011
Revised: December 12, 2011
Accepted: April 28, 2012
Published online: June 21, 2012

Occult hepatitis C virus (HCV) infection, defined as the presence of HCV RNA in liver and in peripheral blood mononuclear cells (PBMCs) in the absence of detectable viral RNA in serum by standard assays, can be found in anti-HCV positive patients with normal serum levels of liver enzymes and in anti-HCV negative patients with persistently elevated liver enzymes of unknown etiology. Occult HCV infection is distributed worldwide and all HCV genotypes seem to be involved in this infection. Occult hepatitis C has been found not only in anti-HCV positive subjects with normal values of liver enzymes or in chronic hepatitis of unknown origin but also in several groups at risk for HCV infection such as hemodialysis patients or family members of patients with occult HCV. This occult infection has been reported also in healthy populations without evidence of liver disease. Occult HCV infection seems to be less aggressive than chronic hepatitis C although patients affected by occult HCV may develop liver cirrhosis and even hepatocellular carcinoma. Thus, anti-HCV negative patients with occult HCV may benefit from antiviral therapy with pegylated-interferon plus ribavirin. The persistence of very low levels of HCV RNA in serum and in PBMCs, along with the maintenance of specific T-cell responses against HCV-antigens observed during a long-term follow-up of patients with occult hepatitis C, indicate that occult HCV is a persistent infection that is not spontaneously eradicated. This is an updated report on diagnosis, epidemiology and clinical implications of occult HCV with special emphasis on anti-HCV negative cases.

Keywords: Occult hepatitis C virus, Hepatitis C virus RNA, Liver, Peripheral blood mononuclear cells, T-cell response