Occult Hepatitis C virus infection Among Hemodialysis Patients

Hepatitis c virus (HCV) is a small enveloped RNA virus belonging to the family Flaviviridae and genus hepacivirus. HCV accounts for approximately 15%-20% cases of acute hepatitis. After acute infection, around 50% to 80% of HCV patients will develop chronic infection. Approximately, HCV infects >185 million individuals worldwide. Chronic hepatitis C (CHC) patients are at high risk to develop life-threatening complications, including cirrhosis in 20% of cases and hepatocellular carcinoma (HCC) at an incidence of 4%-5% per year in cirrhotic patients (Li and Lo, 2015). The prevalence of HCV infection in hemodialysis (HD) patients is persistently greater than in the general population, predominantly in the Mediterranean and developing countries of the Middle and Far East. Despite strict precautions taken on blood products, HCV transmission is still being observed among HD patients. Prolonged vascular exposure puts HD patients at increased risk of infection with blood-borne pathogens, including HBV (hepatitis B virus), HCV and HIV (human immune deficiency virus), from contaminated devices, equipment and supplies, environmental surfaces or attending personnel (Elsayed et al., 2014). Occult HCV infection (OCI), is 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, This 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 (Carreño et al., 2012). 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 (Carreño et al., 2012). Occult HCV has been documented in various populations, including hemodialysis patients, patients with cryptogenic hepatitis and liver cirrhosis, hepatocellular carcinoma, lymphoproliferative disorders, and healthy individuals without evidence of liver disease (Fabrizi et al., 2014). The clinical consequences of occult HCV infection include the risk for HCV transmission from patients with occult HCV within HD units (Fabrizi and Martin, 2008). The gold standard for diagnosis of this occult viral infection is detection of HCV-RNA in liver cells. However, because of the invasive nature of the liver biopsy, other alternatives were studied. It was found that HCV-RNA is also detected in the PBMC of a high percentage of patients with an occult HCV infection (Carreño, 2006). In hemodialysis units routine serologic controls performed biannually including qualitative PCR technology and testing at least every 2 months for alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase (γGTP) levels are important for monitoring viral hepatitis transmission within HD units (Barril et al., 2008). Health care procedures related to nosocomial infections, unsafe drug injection practices, and blood transfusions are key factors in HCV transmission. The guidelines for preventing HCV infection in HD settings recommend fundamental infection control practices, and routine screening of HD patients for HCV. Isolating-HCV infected patients or using dedicated machines for such patients are not advocated, except as necessary during local outbreaks (Etik et al., 2015)