الفهرس 
Hepatitis B virus
Detection methods of HBV genotypesOnly 14 pages are availabe for public view
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Abstract
Hepatitis B virus and hepatitis C virus are the most common causes of chronic liver diseases (CLD) worldwide and can lead to cirrhosis and hepatocellular carcinoma(HCC).
The two viruses share the same mode of transmission, and co-infection by the two viruses is common, particularly in areas where the two viruses are endemic.
HBV infection may occur in HBsAg negative patients with or without serological markers of previous infection (anti-HBs and anti-HBc). Such infection is called occult HBV infection which is defined as the detection of low levels of HBV DNA in serum or liver tissue without detectable HBsAg.
The reasons for the lack of circulating HBsAg may be due to rearrangements in the HBV genome that interfere with gene expression or lead to the production of an antigenically modified S protein, or due to HBV infection with sub detectable levels of HBsAg. Several possibilities have been hypothesized for the mechanisms of occult HBV infection. These include:(i) mutations of HBV-DNA sequence; (ii) integration of HBV-DNA into host’s chromosomes; (iii) infection of peripheral blood mononuclear cells by HBV; (iv) formation of HBV-containing immune complex; (v) altered host immune response; and (vi) interference of HBV by other viruses.
The prevalence of occult HBV is higher in HCV positive patients than HCV negative patients , and may have an impact on the clinical outcome of hepatitis C patients mainly decreasing the response to IFN therapy and increasing the rate of HCC.
The diagnosis of occult HBV infection mainly occurs by the detection of HBV DNA using a highly sensitive PCR technique with or without the detection of HBV markers.
Patients with chronic HCV infection usually show normal or slightly high liver enzymes, whereas in HCV related CLD patients with occult HBV infection, flare in liver enzymes that reached at least five times the upper limit of normal may occur. This may be due to flare in HBV DNA replication , immune activation, and subsequent liver injury.
The aim of the present work was to determine the role of occult hepatitis B virus infection in chronic hepatitis C patients with flare of liver enzymes.
This study was carried out through the period from January 2008 to February 2009. It included 60 HBsAg negative patients who were attending National Liver Institute, Menuofiya University and were diagnosed clinically and serologically as having Chronic hepatitis C virus infection. Both sexes were included and their ages ranged from 21 to 70 years. Patients were divided into 2 groups according to their liver enzymes; 30 patients with normal or slightly high liver enzymes and 30 patients with flare in liver enzymes(≥ 5 times normal values). A sheet was fulfilled for each patient in this study, including the important personal data (e.g. age, sex, history of blood transfusion and history of vaccination).