الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Cell-mediated immune response, especially multi-specific antiviral CD4+ and CD8+ T cells responses are essential for the control of HBV infection. Activated CD4+ T cells usually been divided into two distinct lineages-Th1 and Th2 cells on the basis of their cytokine secretion profiles classically. The Th1/Th2 cytokine balance is likely important in influencing the clinical outcome and disease progression of HBV infection patients. The Th1/Th2 dichotomy has been revisited and the third member of the CD4+ Th cell family . At present, CD4 T helper cells are divided into four major subsets based on their expression profile of transcription factors and secreted cytokines: Th1, Th2, regulatory T cells (Treg) and Th17 cells. Classical Th1 cells secrete IL-2 and IFN-c, whereas Th2 cells secrete IL-4,IL-5, IL- 10 and IL-13. Th2 cytokines are considered to play a profibrotic role in liver fibrosis, whereas Th1 cytokines play a protective role. In addition, Tregs are involved in the regulation of the fibrosis process during HBV infection. Th17 cells are a more recently discovered subset of CD4+ T helper cells and are characterized by the production of their signature cytokine IL-17. Up-regulation of IL-17 produced by Th17 cells has previously been detected in alcoholic liver disease, autoimmune liver disease and viral infectious disease. Intrahepatic IL-17 mRNA expression is increased in acute and chronic liver disease. In addition, in vitro study, IL- 17 cytokine could stimulate DC and monocytes activation, and then increasing proinflammatory cytokine secretion. Thus serum IL-17 level has also been shown to serve as a marker for the severity of acute hepatic injury. Interestingly, although IL-17 cell is a kind of pro-inflammatory cells, IL-17A produced by γδ T cells also was reported to play a critical role in innate immunity against Listeria monocytogenes infection in the liver. Up to now, the role and mechanism of Th17 cells on hepatitis is more and more clear, there are still some concerns need carefully considered, such as the mechanism of Th17 cells on immune activation and hepatitis aggravation in patients with HBV infection, the variant mechanism of harmful or protective role of Th17 and/or IL-17 in different infections or clinical setting is rarely reported. IL-17, its major effector cytokine, can recruit inflammatory cells into livers as well as activate directly hepatic natural immunity systems, such as neutrophils, monocytes and myeloid dendritic cells, to release cytokines that perpetuate chronic inflammation and even IL- 17 may be implicated in the induction of liver fibrosis. IL-17 cells can upregulate antiapoptotic molecules, enhance virusinfected cells survival, impair antiviral cytotoxic CD8+ T cells and thus increase persistent infection . Although a series of reports showed Th17 cells play an important role in the pathogenesis of chronic hepatitis B and liver failure. Our study provides a new insight into understanding the role of Th17 cells to breaking immune tolerance and aggravating necroinflammation in HBV infected patients, and found the baseline difference and dynamic change of Th17 cells in patients with HBV. This study aimed to asses the expression of Interleukin-17- producing CD4+T cells (Th17) in peripheral blood of patients with chronic hepatitis B. The study included fifteen patients suffering from chronic hepatitis B, fifteen suffering from cirrhosis and fifteen are healthy volunteers with matched age and gender were en rolled in the study as a control group. The patients were selected from the outpatient clinics and inpatient of internal medicine departments of the National Liver Institute, Menoufiya University. All groups were subjected to full clinical examination, abdominal ultrasound, hepatitis viral markers (HBs Ag, HCV Ab), liver function tests, HBV RNA PCR and, Th-17 expression. The gained results showed that: - A significant increase in the expression of Th-17 cells in chronic hepatitis B patients compared with healthy control. - A significant increase in the expression of Th-17 cells in chronic hepatitis B cirrhotic patients compared with healthy control.