الفهرس 
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Abstract
Hepatitis C virus (HCV) infection is a blood borne infection The diagnosis of HCV infection is made by the detection of antibodies against HCV (anti-HCV) and/or by detecting the presence of the HCV RNA in serum (lawerance et al,. 2017).
HCV is a leading cause of chronic liver disease worldwide and can lead to a spectrum of liver diseases from mild inflammation with a relatively indolent course to extensive liver fibrosis and consequent cirrhosis, conferring significant morbidity and mortality to affected individuals. Associated hepatocellular carcinoma is a serious complication of CHC-related cirrhosis with an incidence of 5.8% per year in the at-risk population (Burstow et al., 2017).
The liver is the main site of virus replication but it can also replicate at extrahepatic sites such as peripheral blood mononuclear cells (PBMC) 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 (Rezaee-Zavareh et al ., 2015 ).
DAAs are molecules that target specific nonstructural proteins of the virus and results in disruption of viral replication and infection. There are four classes of DAAs, which are defined by their mechanism of action and therapeutic target. The four classes are nonstructural proteins 3/4A (NS3/4A) protease inhibitors (PIs), NS5B nucleoside polymerase inhibitors (NPIs), NS5B non-nucleoside polymerase inhibitors (NNPIs), and NS5A inhibitors (Poordad et al., 2012), (AASLD 2016).
This work aimed to study the possibility of persistence of HCV RNA in peripheral blood mononuclear cells(PBMCs) among post liver transplant patients after successful eradication of HCV RNA from serum by direct acting antiviral agents (DAA) and the impact of different factors on occurrence of such condition.
Our study has found that occult hepatitis C virus infection is still a significant problem even after the era of direct antiviral agents; We detected the HCV RNA in the Peripheral blood mononuclear cells in 2 out of 20 (10%) among post liver transplanted patiens who maintained a sustained virologic response 12 weeks after therapy (SVR12) with direct-acting antiviral (DAA) agents.
We can not find association between OCI and Liver enzymes ,so we suggest the importance of exclude other causes of elevated liver enzymes.
Neither the antiviral treatment type , the treatment duration nor dose and type of immunosuppressive therapy showed a statistically significant relationship with the persistence of HCV in PBMC.
In identifying the risk factors of Occult HCV infection neither history of diabetus , hypertension nor hyperlipidemia are considered a risk factors of occult HCV.