| Abstract: | C型肝炎是影響國人健康甚巨的問題，目前尚無有效的疫苗可以防治，因此治療成為一重要課題。已知HCV病毒蛋白Non-structural 5A (NS5A)區域上的ISDR (Interferon Sensitivity Determining Region)序列，可能會與干擾素作用過程中的蛋白激PKR (Protein Kinase R)作用，因此ISDR序列發生突變可能會影響干擾素治療的效果。在本研究中，70位病患感染C型肝炎病毒的患者接受干擾素與Ribavirin治療，其中有52位患者感染基因型1b，另外18位患者則為混合感染。藉由患者治療前後ALT值作為評估療效的標準，探討干擾素與Ribavirin治療療效間與病毒序列ISDR突變間是否具有相關性，並檢測病人的治療後各項肝功能指數、血液生化檢驗值、腎功能指數、以及病毒在血清中的含量，分析治療效果與各項檢測值之間的關係。與HCV 1b病毒的原型核酸序列比較發現，所有病人體內的病毒核酸序列皆有七個位置發生突變，但不影響胺基酸序列的表現為無義突變(missense Mutation)。比較病毒胺基酸序列並分析與療效間相關性，結果發現70位病人中有6位病人的ISDR區域胺基酸序列發生突變，包括治療後復發者有2人、治療有效者有3人及治療無效者有1人。Chi square test統計分析後發現，病人病毒胺基酸突變與治療效果間無明顯相關性(p=0.324)；其他檢測值與療效間的比較發現，腎功能指數BUN與療效在統計上具有意義，BUN越高者的療效較差(p=0.046)。將病人更進一步分類為單一基因型病毒感染與不同基因型病毒混合感染兩群後發現，單獨感染HCV-1b病人療效與病毒胺基酸突變無相關性(p=0.480)，而混合不同基因型病毒其胺基酸序列則未見突變。由本實驗結果發現，干擾素與Ribavirin治療療效可能不受病毒ISDR區域變異性所影響。
Chronic Hepatitis C infection has been an important health topic in Taiwan since no effective and protective vaccines available for prophylaxis and then treatment becomes the practicable way for blocking the disease progression to hepatoma or cirrhosis. The interaction between Interferon Sensitivity Determine Region (ISDR) of Non-structural 5A (NS5A) of HCV and protein kinase R (PKR), an interferon-responsive protein has been reported and therefore, it was speculated that mutations within the ISDR region may interfere the efficiency of interferon therapy. This hypothesis has been verified by several studies; however, conflicting results were also presented. In this study, 70 patients with chronic HCV infection, 52 patients were infected with genotype 1b and the other 18 patients were infected with mixed genotypes (1a+1b or 1b+2a), who have undergone the interferon-ribavirin therapy were recruited for evaluating the influences of various host and viral factors on the treatment efficiency. Before the treatment, serum samples were collected from every patient for routine laboratory tests and viral sequence analysis. As the results shown, certain host factors, including ALT, BUN and TBIL, have relationships, although not statistically significant, to the treatment efficiency insignificant while mutation of ISDR region has no impact on the treatment efficiency although several mutations, including serine to praline at 2210, histidine to arginine at 2218, histidine to arginine at 2219, aspartic acid to arginine at 2223, alanine to serine at 2224, and isioleucine to phylalanine at 2227. In addition, 7 missense mutations of nucleotides, including T6971C, T6996C, C7036T, G7059A, C7068T, T7076C and A9081G, were identified in all isolates which may present local variations. The impact of these variations and mutations on the binding activity of resulting NS5A proteins to PKR warrants further investigation. |
