Quantitative analysis of HBV cccDNA from clinical specimens: correlation with clinical and virological response during antiviral therapy

Attempts to investigate changes in various forms of intrahepatic hepatitis B virus (HBV) DNA during antiviral therapy have been hampered by limitations in technologies and scarcity of adequate tissue for analysis. We used a sensitive, specific assay to detect and quantitate covalently closed circular DNA (cccDNA) from total intrahepatic HBV DNA in clinical liver specimens. Total HBV DNA and cccDNA from 21 needle-biopsy specimens were quantified, with levels ranging from 0.1 to 9.8 copies/cell and 0.3 to 491.0 copies/cell, respectively. Then, we performed the same determinations on baseline and week-52 liver needle-biopsy specimens from eight patients enrolled in a clinical trial and evaluated the association between intrahepatic HBV DNA levels and serological and virological endpoints. In most patients, levels of intrahepatic HBV DNA, including cccDNA, decreased over the 52-week study, regardless of therapy or serological outcome. Higher ratios of cccDNA to total HBV DNA were detected at week 52 than at baseline indicating a shift in predominance of nonreplicating virus in posttreatment specimens. In patients who achieved treatment-related or spontaneous hepatitis B e antigen (HBeAg) responses, including those harbouring tyrosine-methionine-aspartate-aspartate-mutant HBV, levels of intrahepatic and serum HBV DNA suppression were greater than those in patients without HBeAg responses. In conclusion, this pilot study of intrahepatic HBV replicative forms in patients with chronic hepatitis B indicated that total intrahepatic and, specifically, cccDNA levels are not static but change as a reflection of serological and virological events.     

Validation of a sensitive and specific real‐time PCR for detection and quantitation of hepatitis B virus covalently closed circular DNA in plasma of chronic hepatitis B patients

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) serves as a template for viral replication and plays a role in persistence of HBV infection. The origin and significance of cccDNA in plasma however, is not well understood. A sensitive, specific, and reproducible real‐time PCR for detection and quantitation of cccDNA in plasma of chronic hepatitis B patients was developed and validated. Four HBV DNA reference panels, and 96 plasma samples of chronic hepatitis B patients were analyzed. Results were compared with total HBV DNA levels, individual ALT levels and the Histology Activity Index (HAI). This cccDNA assay had a lower limit of detection at 15 copies/PCR, a lower limit of quantitation at 91 copies/PCR and a correlation coefficient (R) of 0.98 (P < 0.0001). cccDNA was detected in two of four international panels. Significant correlation was found between cccDNA and total HBV DNA levels in both panels (R = 0.96, and R = 0.43) and in samples of the chronic hepatitis B patients (R = 0.88, P < 0.0001). In 57% of these samples cccDNA was detectable. Mean level of cccDNA was 0.16% of total HBV load. Plasma cccDNA levels were higher in HBeAg positive samples than in HBeAg negative samples (4.91 log copies/ml vs. 3.88 log copies/ml, P < 0.0001). Levels of total HBV DNA and HBV genotype did not influence cccDNA detection. ALT levels and HAI‐score were not correlated with plasma cccDNA levels. These findings suggest that cccDNA levels in plasma are not the result of increased hepatocyte degeneration, but indicate that other mechanisms might be responsible. J. Med. Virol. 81:988–995, 2009. © 2009 Wiley‐Liss, Inc.     

HBsAg plasma level kinetics: a new role for an old marker as a therapy response predictor in vertically infected children on combination therapy

We aimed to investigate the ability of HBsAg plasma level kinetics to predict therapy response by studying 23 children with infancy‐acquired chronic hepatitis B (CHB) during combination sequential therapy with lead‐in lamivudine (LAM) and add‐on interferon‐α (IFN‐α) [5 responders (R = anti‐HBs seroconversion) and 18 nonresponders (NR)] and to assess their relationship with pretreatment intrahepatic HBV‐DNA and cccDNA and HBsAg and HBcAg liver expression. Plasma HBsAg levels were measured in samples before (treatment week 0 = TW0), during (TW9, TW28, TW52) and after (follow‐up week = FUW24) therapy by Abbott ARCHITECT^® assay [log₁₀IU/mL]. Baseline liver HBV‐DNA and cccDNA were quantified by real‐time TaqMan PCR [log₁₀copies/ng genomic DNA]. HBsAg and HBcAg liver expression was evaluated by immunostaining of formalin‐fixed, paraffin‐embedded specimens [number of positive cells/1000 hepatocytes]. All results are presented as medians. Plasma: at baseline, on‐treatment and during follow‐up, HBsAg levels were lower in R than NR (TW0: 4.36 vs 4.75;TW28: 2.44 vs 4.35;TW52: 0 vs 4.08 and FUW24: 0.17 vs 4.35, all P < 0.05). Liver: baseline HBV‐DNA (3.82 vs 4.71, P = 0.16) and cccDNA (1.98 vs 2.26, P = 0.18) tended to be lower in R than NR, HBsAg expression was lower in R than NR (0.5 vs 4.7, P = 0.03), and HBcAg expression was similar between R and NR. There were positive correlations between plasma HBsAg levels and liver HBV‐DNA (r = 0.44, P = 0.04), cccDNA (r = 0.41, P = 0.04) and HBsAg liver expression (r = 0.38, P = 0.05). Lower baseline HBsAg plasma levels, lower HBsAg expression in liver and on‐treatment decline of plasma HBsAg levels heralds HBsAg clearance and response to treatment in tolerant children with CHB.     

肝移植术后肝组织中HBV cccDNA的表达及临床意义

目的探讨肝移植术后患者肝组织内乙型肝炎病毒共价闭合环状DNA(HBV cccDNA)的表达及其临床意义。方法应用原位聚合酶链反应及免疫组织化学法检测2004年4月至2007年4月在北京地坛医院肝移植术后出现HBV再感染的25例患者及10例肝移植术后未出现HBV再感染者肝组织中HBV cccDNA及乙型肝炎表面抗原(HBsAg)、乙型肝炎核心抗原(HBcAg)、前-S1的表达。结果在35例标本中检测到cccDNA阳性的有22例(62.9%),阳性信号为紫蓝色呈块状或颗粒状,定位于细胞核。25例术后出现HBV再感染的患者其HBV cccDNA阳性率显著高于未出现HBV再感染者(84%对10%,P<0.01)。HBV cccDNA和HBcAg均为阳性的有20例,有2例患者肝组织中HBcAg阴性,但HBV cccDNA检测为阳性。肝组织中HBV cccDNA的表达阳性率与HBcAg具有高度一致性(Kappa=0.755,P<0.01)。结论肝移植患者肝组织中HBV cccDNA阳性表达可能与乙型肝炎再感染具有密切关系。     

Baseline and kinetics of serum hepatitis B virus RNA predict response to pegylated interferon‐based therapy in patients with hepatitis B e antigen‐negative chronic hepatitis B

Serum hepatitis B virus (HBV) RNA has emerged as a novel biomarker of treatment response. This study aimed to investigate the role of this marker in predicting long‐term outcome of patients with hepatitis B e antigen (HBeAg)‐negative chronic hepatitis B (CHB) receiving pegylated interferon (PEG‐IFN)‐based therapy. Serial serum samples from 91 patients with HBeAg‐negative CHB previously treated with PEG‐IFN alone or combined with entecavir in a randomized trial were retrospectively analysed. HBV RNA quantification was examined by droplet digital PCR. At the end of 3 years post‐treatment follow‐up, maintained virological response (MVR, HBV DNA < 2000 IU/mL), and hepatitis B surface antigen (HBsAg) clearance were achieved in 37.4% (34/91) and 7.7% (7/91), respectively. Baseline serum HBV RNA concentrations correlated with HBV DNA and covalently closed circular DNA but did not correlate with HBsAg levels. Multiple regression analysis showed that pre‐treatment HBV RNA and HBsAg were independently associated with MVR and HBsAg clearance. Baseline HBV RNA (cut‐off 2.0 log₁₀ copies/mL) had a positive predictive value (PPV) and a negative predictive value in predicting MVR of 80.8% and 80.0%, respectively. At the same cut‐off value, PPV and NPV for predicting HBsAg clearance were 30.8% and 95.4%, respectively. At week 12 during therapy, HBV RNA level ≥ 2 log₁₀ copies/mL displayed high NPVs of achieving MVR and HBsAg clearance (95% and 100%, respectively). In conclusion, the measurement of HBV RNA prior to PEG‐IFN‐based therapy could identify patients with high probability of MVR. In addition, HBV RNA kinetics may serve as a promising “stopping rule” in patients infected with HBV genotypes B or C.     

Relationship between serum hepatitis B virus DNA and surface antigen with covalently closed circular DNA in HBeAg‐negative patients

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is responsible for viral persistence. This study aimed to investigate the serum surrogate markers for cccDNA and to evaluate the intrahepatic viral events associated with disease activity in HBeAg‐negative chronic hepatitis B patients. Thirty‐three treatment‐naïve patients with a negative HBeAg who had a liver biopsy were studied. Active disease was defined as a serum alanine aminotransferase >40 IU/L and a serum HBV DNA >10,000 copies/ml. This study showed significant correlation between serum HBV DNA and both log cccDNA (r = 0.41, P = 0.018) and log total intrahepatic HBV DNA (r = 0.71, P < 0.0001). No significant correlation was observed between serum HBsAg and log cccDNA (P = 0.15) or log total intrahepatic HBV DNA (P = 0.97). Fourteen and 19 patients had inactive and active disease, respectively. The median log cccDNA and log total intrahepatic HBV DNA (copies/10⁶ cells) were significantly higher in patients with active disease compared with those with inactive disease (4.11 vs. 3.53, P = 0.03 and 5.46 vs. 4.64, P < 0.001, respectively). The HBV replicative efficiency, defined as the ratio of serum HBV DNA to cccDNA, was approximately 20% higher in patients with active disease. No significant difference was observed in the HBsAg levels and the ratio of serum HBsAg to cccDNA between the two groups. In conclusion, serum HBV DNA, but not HBsAg, reflects the amount of cccDNA and the replication efficiency of HBV in patients with HBeAg‐negative chronic hepatitis B. J. Med. Virol. 82:1494–1500, 2010. © 2010 Wiley‐Liss, Inc.     

乙型肝炎病毒cccDNA巢式-实时荧光定量PCR法的建立及应用

目的建立检测HBV共价闭合环状（cccDNA）的巢式-荧光定量PCR法,检测外周血单核细胞（PBMC）及骨髓单核细胞（MMNC）中cccDNA。方法根据HBV cccDNA与松弛结构DNA（rcDNA）结构上的差异,设计2对跨缺口的特异性引物及下游的特异性TaqMan探针。根据Mung Bean Nuclease对rcDNA与cccDNA作用的不同,使cccDNA扩增而使rcDNA降解,分别用外引物及内引物进行PCR反应,再用荧光探针进行实时荧光定量PCR,根据阳性参照物,计算出检测标本定量值。结果成功建立了HBV cccDNA巢式-荧光定量PCR的检测方法,线性范围为5.0×102～3.9×107拷贝/ml。用上述方法检测25例慢性乙型肝炎（CHB）及肝硬化血清HBV DNA阳性患者PBMC中cccDNA,7例MMNC中cccDNA,21例健康献血者PBMC cccDNA,骨髓标本中有3例cccDNA阳性,25例外周血标本中有9例cccDNA阳性。结论巢式-荧光定量PCR法可检测乙型肝炎患者PBMC及MMNC中的HBV cccDNA含量。PBMC及MMNC中可检测到HBV cccDNA。