Detection The Frequency Of CD4～+CD25～+ Treg Cells And Investigation Its Role In Suppression Of CD4～+ Th1 Cell Responses From Chronic HCV-infected Patients

Hepatitis C virus (HCV) is a major public health problem, affecting an estimated 200 million people worldwide , which infects 1.9% of the population in developed countries, and more than 22% of the population in some countries. In our country, HCV-infected subjects account for 40% of all worlds. A striking feature of infection with HCV is the very high rate of chronicity with 80 % of cases developing persistent viraemia. The virus can go on to cause fibrosis, and ultimately death through liver failure or hepatocellular carcinoma. The mechanisms that cause both viral persistence and hepatic pathology are unknown.There is growing evidence that virological features of HCV are associated with different clinical manifestations and response to therapy. HCV genome contains a hypervariable region 1 at the upstream end of the envelope 2/nonstructurall (E2/NS1) gene segment. It has been suggested that thehigh mutation rate in hypervariable region 1 may generate variants to escape host immune surveillance, leading to persistent infection. Genotype 1b is associated with more severe liver disease and with lower response rates for antiviral therapy, compared with types 2 and 3. A major advance in understanding the regulation of specific immune responses to...