Electronic Physician (ISSN: 2008-5842) http://www.ephysician.ir December 2015, Volume: 7, Issue: 8, Pages: 1619-1625, DOI: http://dx.doi.org/10.19082/1619 Corresponding author: Dr. Samya Hassan El-shishtawy, Lecturer of Internal Medicine, Nephrology Department, Theodor Bilharz Research Institute, Giza, Egypt. Tel: +20.1003661563 Samya_shishtawy@yahoo.com Received: September 06, 2015, Accepted: October 09, 2015, Published: December 2015 iThenticate screening: October 22, 2015, English editing: November 03, 2015, Quality control: November 08, 2015 © 2015 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial- NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Page 1619 Occult Hepatitis C Virus Infection in Hemodialysis Patients; Single Center Study Samya El-shishtawy 1 , Nevine Sherif 1 , Emad Abdallh 1 , Laila Kamel 2 , Mohamed Shemis 3 , Abdel Aziz Ali Saleem 4 , Haitham Abdalla 4 , Hesham Gamal el Din 5 1 Nephrology Department, Theodor Bilharz Research Institute, Giza, Egypt 2 Clinical Pathology Department Theodor Bilharz Research Institute, Giza, Egypt 3 Biochemistry Department, Theodor Bilharz Research Institute, Giza, Egypt 4 Department of Tropical Diseases, Theodor Bilharz Research Institute, Giza, Egypt 5 Clinical Pathology Department National Research Center, Giza, Egypt Type of article: Original Abstract Introduction: A new form of hepatitis C virus infection, known as occult hepatitis C virus (HCV) infection, is characterized by the presence of HCV_RNA in the liver or peripheral blood mononuclear cells (PBMCs). However, no serological markers of infection occur and there is not as much damage to the liver damage as is produced by chronic hepatitis C. There is a high incidence of HCV infection among hemodialysis patients, there is significant concern about viral transmission. HCV infection is a major problem in hemodialysis (HD) units even though blood products are screened for anti-HCV antibodies and other precautions are taken. The aim of this study was to determine the prevalence of occult HCV infection in PBMC in chronic hemodialysis (CHD) patients in the dialysis unit at Theodor Bilharz Research Institute (TBRI) with HCV antibodies and HCV RNA negativity irrespective of their liver function tests. Methods: Fifty-three patients who were repeatedly were anti-HCV negative and serum HCV-RNA negative and on regular hemodialysis for > six months were enrolled in the study, which was conducted in the dialysis unit of Nephrology Department at TBRI; there were 10 healthy matched controls. The patients were classified into two groups according to the result HCV RNA in their PBMCs. Serological markers of HCV infection, including anti- HCV antibody and serum HCV-RNA, were repeatedly negative for all patients included in the study. We collected serum and PBMC samples from the patients on the day they entered the study. The test of all serum samples for anti-HCV antibodies and HCV-RNA was repeated by RT-PCR to ensure that the patients did not have these HCV serologic markers, We also measured their ALT and GGT levels. Results: Occult hepatitis C virus infection (OCI) was detected in 15.1% of our CHD patients without any evidence of chronic liver disease. Conclusion: Occult HCV infection was present among the hemodialysis patients irrespective of whether they had persistent abnormal values of liver enzymes for which no cause had been identified. Further study is required to determine the clinical significance of occult HCV infections in these patients. Keywords: hepatitis C, hemodialysis, occult infection 1. Introduction Chronic infection with hepatitis C virus (HCV) is a serious public health problem associated with increased morbidity and mortality, and it affects approximately 2.8% of the world’s population (1, 2). The distribution of this infection varies significantly between various geographical locations (3). It was found that about 20% of Egypt’s population had HCV infections, the highest prevalence anywhere in the world (4). The International Committee on Taxonomy of Viruses has classified hepatitis C virus as being within the genus Hepacivirus, family Flaviviridae. Six major phenotypes (HCV-1 to HCV-6) have been described, each of which contains multiple subtypes with different