Introduction
Hepatitis C is one of the most common liver diseases around the world. It is caused by hepatitis C virus (HCV) and a significant number of patients progress towards chronic hepatitis, hepatocellular carcinoma (HCC) and liver cirrhosis (Hoofnagle et al.,2002).
Viral infection is the major cause of liver cirrhosis in about 20% of patients that after 10 years lead to HCC in 3% of these patients per year (Zein et al., 2000).
The prevalence of HCV infection in various locations around the world ranges from 0.5 to 10% (Brinster et al., 2001). Currently, almost 200 million people of the world population are infected with HCV (Butt S et al.,2010).
HCV genotypes and many subtypes have been identified and are generally studied for epidemiology, molecular diagnosis, development of vaccines, and clinical management of the infection (Ali et al., 2010).
Still no vaccine is available and the standard treatment is neither economical nor fully effective in all the patients (Arichi et al., 2000).
Core gene is one of the most conserved regions of HCV genome, involved in detection, quantitation and genotyping (Ohno et al., 2007).
It also interact with the envelop protein (E1) and thus forms the HCV capsid (Lunel et al., 1994).
The core antigen-based assays has been reported to be helpful for the measurement of HCV RNA among the patients undergoing dialysis and shown to be useful indicator for HCV viremia in asymptomatic carriers (Agha et al., 2004) .
It has also been reported that the HCV core antigen-based methods are useful for the quantitative measurement of HCV with respect to rapidness, easiness and low cost (Okazaki et al., 2008).
Moreover, HCV core antigen-based assay can identify up to 94% of viraemic donations given during the seronegative window phase of infection. The performance of the assay appears to be suitable for large-scale screening of blood donations (Lee SR et al., 2001).
To combat and timely diagnose HCV, community based serologic screening is of extreme significance due to dodgy trend of asymptomatic nature of the HCV infection (Lee SR et al., 2001).For this purpose rapid, economical, sensitive and more specific assays are needed.
The present work involved an effort to design such an assay using purified HCV core antigen from local isolates and to check out the opportunity of these cloned HCV core gene to be further employed in the possibility of vaccine development. We also describe the application of recombinant HCV core antigen from local isolates to formulate more specific screening assay for Egyptian population where HCV is becoming a big health problem.
Aim of the study:
To evaluate the role of core antigen as a marker for diagnosis of HCV infection in comparison to HCV RNA as detected by reverse transcription polymerase chain reaction (RT-PCR).