Application Of Microarray In The Study On Molecular Diagnosis And Gene Expression Profiles Of Viral Hepatitis

Hepatitis viruses are the most common cause of acute and chronic hepatitis. Chronic infection by hepatitis viruses affects over 500 million people worldwide. Viral hepatitis is associated with significant morbidity and mortality and is considered to be a major public health problem in most areas of the world. Development of earlier and more sensitive assays may contribute greatly to the diagnosis, treatment, and prevention. In China, approximately 18 million people have developed chronic hepatitis B after exposure to the hepatitis B virus (HBV) and the incidence rate of HBV infection is 158/100,000 each year. Up to 40% of these will eventually develop serious hepatic complications. The infection can cause acute and chronic liver disease including cirrhosis and hepatocellular carcinoma (HCC). The risk of incidence rate of HCC in the individuals that have developed chronic hepatitis B is 300 times higher than those have not. Infection with hepatitis C virus (HCV) has been identified as themajor cause of post-transfusion non-A, non-B hepatitis, and is considered to be a major public health problem in most areas of the world, raising the issues of its diagnosis, treatment, and prevention. In China, the total rate of HCV infection is 1-3%. About 70-80% of the patients have developed chronic hepatitis and the transformation efficiency of HCV is drastically higher than that of hepatitis B. About 5% of infected people have developed HCC within 20-30 years. Up to now, there is no effective measure to prevent and control HCV infections, and no vaccine is commercially available. As a result, early diagnosis is an effective way to prevent and control HCV infections. HCV is classified into six genotypes and an increasing number of subtypes based on degree of genomic sequence divergence. The HCV genotype and subtypes have a characteristic in geographical distribution. Recently, a number of studies have suggested that the severity of liver disease and the outcome of therapy may be genotype-dependent. Infection with type 1 of HCV or mixed-genotype is associated with more severe liver disease and a poorer response to IFN therapy. The discrepancy response to IFN treatment and the degree of viremia is different in different genotypes. The hepatitis D virus (HDV), a defective virus, requires the supply of hepatitis B surface antigen (HbsAg) envelope for its assembly and transmission. During both acute and chronic infections, HDV infection often leads to a more severe disease.