Preiss Scott, Littlejohn Margaret, Angus Peter, Thompson Alex, Desmond Paul, Lewin Sharon R, Sasadeusz Joe, Matthews Gail, Dore Gregory J, Shaw Tim, Sozzi Vitini, Yuen Lilly, Lau George, Ayres Anna, Thio Chloe, Avihingsanon Anchalee, Ruxrungtham Kiat, Locarnini Stephen, Revill Peter A
Victorian Infectious Diseases Reference Laboratories, Research and Molecular Development, North Melbourne, Victoria, Australia.
Hepatology. 2008 Sep;48(3):741-9. doi: 10.1002/hep.22386.
Defective hepatitis B virus DNA (dDNA) is reverse-transcribed from spliced hepatitis B virus (HBV) pregenomic messenger RNA (pgRNA) and has been identified in patients with chronic HBV (CH-B). The major 2.2-kb spliced pgRNA encodes a novel HBV gene product, the hepatitis B splice protein (HBSP) via a deletion and frame shift within the polymerase. Although spliced RNA and HBSP expression have been associated with increased HBV DNA levels and liver fibrosis, the role of dDNA in HBV-associated disease is largely undefined. Our aims were to (1) compare the relative proportions of dDNA (% dDNA) in a range of HBV-infected serum samples, including patients with human immunodeficiency virus (HIV)/HBV coinfection and HBV-monoinfected persons with differing severities of liver disease, and (2) determine the effect of mutations associated with drug resistance on defective DNA production. Defective DNA was detected in 90% of persons with CH-B. There was no significant difference in the relative abundance of dDNA between the monoinfected and HIV/HBV-coinfected groups. We also found no association between the % dDNA and alanine aminotransferase, hepatitis B e antigen status, HBV DNA levels, fibrosis levels, compensated or decompensated liver cirrhosis, genotype, or drug treatment. However, the % dDNA was significantly lower in individuals infected with lamivudine-resistant (LMV-R) HBV compared with wild-type HBV (P < 0.0001), indicating that antiviral drug resistance alters the balance between defective and genomic length DNA in circulation. Experiments in vitro using HBV encoding LMV-R mutations confirmed these results.
Our results identified no association between dDNA and parameters associated with disease status and suggested that the relative abundance of dDNA is largely dependent on the integrity of the HBV polymerase and is unrelated to the severity of liver disease.
缺陷型乙型肝炎病毒DNA（dDNA）由剪接后的乙型肝炎病毒（HBV）前基因组信使RNA（pgRNA）逆转录而来，已在慢性HBV（CH-B）患者中被鉴定出。主要的2.2kb剪接pgRNA通过聚合酶内的缺失和移码编码一种新型HBV基因产物，即乙型肝炎剪接蛋白（HBSP）。尽管剪接RNA和HBSP表达与HBV DNA水平升高及肝纤维化有关，但dDNA在HBV相关疾病中的作用在很大程度上尚不清楚。我们的目的是：（1）比较一系列HBV感染血清样本中dDNA的相对比例（% dDNA），包括人类免疫缺陷病毒（HIV）/HBV合并感染患者以及不同肝病严重程度的HBV单感染个体；（2）确定与耐药相关的突变对缺陷型DNA产生的影响。在90%的CH-B患者中检测到了缺陷型DNA。单感染组和HIV/HBV合并感染组之间dDNA的相对丰度没有显著差异。我们还发现% dDNA与丙氨酸氨基转移酶、乙肝e抗原状态、HBV DNA水平、纤维化水平、代偿期或失代偿期肝硬化、基因型或药物治疗之间没有关联。然而，与野生型HBV相比，拉米夫定耐药（LMV-R）HBV感染个体中的% dDNA显著更低（P < 0.0001），这表明抗病毒耐药性改变了循环中缺陷型和基因组长度DNA之间的平衡。使用编码LMV-R突变的HBV进行的体外实验证实了这些结果。
我们的结果表明dDNA与疾病状态相关参数之间没有关联，并提示dDNA的相对丰度在很大程度上取决于HBV聚合酶的完整性，与肝病严重程度无关。
