HBV天然免疫的研究进展

HBV入侵人体时,天然免疫首先发挥重要的作用。成人感染HBV后,常常会被自发清除,然而在出生或者年幼时期感染HBV时,病情更容易慢性化并且迁延终生。在HBV感染初期,天然免疫应答对病毒复制的抑制发挥了重要作用,HBV感染的转归取决于宿主和病毒共同作用。简述了近年来有关HBV与宿主天然免疫中发挥重要作用的细胞类型、细胞因子、信号通路及其作用机制的研究进展,并指出了其在临床治疗方面的潜在价值。     

Reactivation of hepatitis B virus during interferon‐free therapy with daclatasvir and asunaprevir in patient with hepatitis B virus/hepatitis C virus co‐infection

Direct‐acting antiviral agents (DAA) for hepatitis C virus (HCV) are not effective for hepatitis B virus (HBV), which may be suggestive of reactivation of anti‐HBe hepatitis during interferon (IFN)‐free DAA therapy in HBV/HCV co‐infected patients with inactive HBV. A 69‐year‐old male patient was diagnosed with chronic hepatitis due to HBV/HCV co‐infection with serum levels of alanine aminotransferase (ALT) of 94 U/L, HCV RNA of 4.2 log IU/mL and HBV DNA of 2.5 log copies/mL. HCV was thought to be responsible for the hepatitis activity because of low level of HBV core‐related antigen (3.1 log U/mL). He was treated with combination therapy of daclatasvir and asunaprevir. Serum ALT gradually increased, and reached 237 U/L on day 43 in spite of undetectable HCV RNA. Serum HBV DNA was increasing to 7.0 log copies/mL at that time. The treatment was stopped due to suspicion of drug‐induced liver injury and/or HBV reactivation. Administration of entecavir reduced HBV DNA levels, followed by improvement in ALT levels. This report proposes that close monitoring of HBV DNA during the anti‐HCV DAA therapy and the commencement of anti‐HBV therapy with nucleoside analogs after the increase of HBV DNA should be considered in patients with HBV/HCV co‐infection.     

Host immunity influences disease progression and antiviral efficacy in humans infected with hepatitis B virus

Hepatitis B virus (HBV) infection can lead to several severe liver diseases, including hepatitis, cirrhosis and hepatocellular carcinoma, although the underlying mechanisms responsible for the clinical outcome have not been well characterized. In this review, we retrospectively examine the history of immunological responses to HBV infection and summarize the current understanding of innate and adaptive immunity in the context of HBV-associated liver disease. Recent data indicate that the interaction between HBV and the host immune response not only substantially drives disease progression, but also significantly influences antiviral efficacy in HBV-infected individuals. Advances in the field have provided insight into the immunopathology of HBV infection. Based on the characteristics of host immune responses in patients with HBV infection, a ‘climbing slope hypothesis’ is proposed to suggest that therapeutic strategies aimed at modulating the immune activity of the host may represent a complementary approach to antiviral drug treatment for the management of chronically HBV-infected patients.     

Histological changes during clearance of chronic hepatitis B virus infection by adoptive immunity transfer

BACKGROUND: Serological clearance of hepatitis B surface antigen (HBsAg) has been described after reception of hepatitis B surface antibody positive marrow, via allogeneic bone marrow transplantation (BMT). Histological changes during the clearance of HBsAg are unknown. METHODS AND RESULTS: We described two chronic hepatitis B carriers (both hepatitis B e antigen negative), who cleared HBsAg after allogeneic bone marrow transplantation. Both received hepatitis B surface and core antibody positive human leucocyte antigen identical donors' marrow and had serological clearance of HBsAg 15 and 7 weeks after allogeneic BMT, respectively. Both events were preceded by hepatic flare. Both patients were also treated with famciclovir for the prevention of hepatitis B reactivation after BMT. Histological examination during the flare showed only mild necroinflammatory activity with multiple foci of confluent necrosis, associated with moderate lymphocytic infiltration. The majority of these lymphocytes were cluster of differentiation (CD) 8 positive. Using immunohistochemistry, there was no detectable hepatic expression of hepatitis B core antigen. However, HBsAg was positive, mainly in the area of confluent necrosis. Using in situ hybridization, hepatitis B virus (HBV) DNA was detected in the nucleus of 5% of hepatocytes, but not in the cytoplasm. CONCLUSIONS: At their last follow up, 22 and 16 months after BMT, the serum of both patients remained HBsAg negative, hepatitis B surface antibody positive and HBV-DNA negative by branched DNA assay.     

Factors associated with isolated anti‐hepatitis B core antibody in HIV‐positive patients: impact of compromised immunity

Summary. In regions that are hyperendemic for chronic hepatitis B virus (HBV) infection, prevalence of and risk factors associated with isolated anti‐hepatitis B core antibody (anti‐HBc) in HIV‐positive patients are less well described. HIV‐positive patients who were tested for hepatitis B surface antigen (HBsAg), anti‐hepatitis B surface antibody (anti‐HBs) and anti‐HBc at designated hospitals for HIV care in Taiwan were included for analysis. HBV DNA was detected by real‐time polymerase chain reaction in patients with and without isolated anti‐HBc. Of 2351 HIV‐positive patients, 450 (19.1%) were HBsAg positive, 411 (17.5%) were anti‐HBc positive alone and 963 (41.0%) for both anti‐HBs and anti‐HBc. Compared with patients who were positive for both anti‐HBs and anti‐HBc, patients with isolated anti‐HBc were older, less likely to have anti‐hepatitis C virus antibody (anti‐HCV), had lower CD4 lymphocyte counts and higher plasma HIV RNA loads. Older age (adjusted odds ratio, 1.029; 95% confidence interval, 1.015–1.043) and CD4 <100 cells/μL (adjusted odds ratio, 1.524; 95% confidence interval, 1.025–2.265) were independently associated with isolated anti‐HBc by logistic regression, while presence of anti‐HCV and injecting drug use were not. HBV DNA was detectable in 8.3% of 277 patients with isolated anti‐HBc and 14.3% of 56 patients with both anti‐HBs and anti‐HBc (P = 0.160). In a country hyperendemic for HBV infection, HIV‐positive patients at older age and with CD4 <100 cells/μL were more likely to have isolated anti‐HBc, suggesting that compromised immunity plays a role in the presence of this marker.     

Successful clearance of hepatitis B virus after allogeneic stem cell transplantation: beneficial combination of adoptive immunity transfer and lamivudine

We report a 38-yr-old male with acute lymphocytic leukemia (ALL), whose serological tests for the hepatitis B virus (HBV) before transplantation showed a chronic carrier status, and a liver biopsy specimen revealed chronic liver injury because of HBV. The patient underwent allogeneic peripheral blood stem cell transplantation (PBSCT) from his sibling who was hepatitis B surface antibody (HBsAb) positive. He had received lamivudine treatment for the prophylaxis of HBV reactivation during cytotoxic chemotherapy, and lamivudine administration continued after transplantation. Successful engraftment was documented 3 wk after PBSCT, and clearance of the hepatitis B surface antigen (HBsAg) was observed 2 months after PBSCT. Liver function tests transiently showed a mild elevation of aminotransferases on day 25, although this returned to normal after the dose escalation of the immunosuppressive agent. We presume that the combination of adoptive immunity transfer by bone marrow transplantation (BMT) from an HBsAb-positive donor and antiviral drugs such as lamivudine is beneficial in clearing HBV in chronic carriers.     

Efficacy of antepartum administration of hepatitis B immunoglobulin in preventing mother‐to‐child transmission of hepatitis B virus

The aim of this study was to investigate the efficacy of antepartum administration of three doses of hepatitis B immunoglobulin (HBIG) in interrupting mother‐to‐child transmission (MTCT) of hepatitis B virus (HBV). In this trial, a total of 728 HBeAg‐positive pregnant women with chronic HBV infection who had an HBV DNA level higher than 6log₁₀ copies/mL were enrolled. They were divided into three groups based on individual preference. Subjects in group A and group B received 200 IU (unit) HBIG and 400 IU (unit) HBIG intramuscularly once a month at the third, second and first month before delivery, respectively. Subjects in the control group (C) received no special treatment. All the infants received passive‐active immunoprophylaxis. The HBsAg‐positive rate of all infants at 7‐12 months of age was 5.1% (37/728). Specifically, the HBsAg‐positive rate of infants was comparable in all three groups (5.3% vs 5.1% vs 5%, P = 0.988). No significant difference was found in anti‐HBs levels between the infants aged 7‐12 months in the three groups (P = 0.469). HBV DNA levels of the umbilical cord blood in the HBV‐infected group were higher than those in the uninfected group (5.2 vs 3.4log₁₀ copies/mL, P < 0.001), and these with family history of HBV infection were also higher (45.9% vs 28.5%, P = 0.034). To conclude, administration of passive‐active immunoprophylaxis to infants contributed to effective prevention of the MTCT of HBV; extra antepartum administration of HBIG during pregnancy could not decrease the rate of MTCT or increase the anti‐HBs levels of infants born to HBsAg‐positive mothers with HBV DNA higher than 6log₁₀ copies/mL.     

急性乙型肝炎患者乙型肝炎病毒清除的临床观察

目的探讨急性乙型肝炎患者血清乙型肝炎病毒(HBV)清除及临床转归的机制。方法动态观察29例住院急性乙型肝炎患者肝功能、HBV DNA、HBV血清标志物的变化,检测其T细胞亚群并与慢性乙型肝炎患者进行比较。结果急性乙型肝炎早期患者HBV广泛抑制,两例患者HBV得到清除,随肝功能的恢复所有患者HBV DNA在较短时间内转阴、HBeAg与HBV DNA几乎同时转阴,肝功能恢复正常时有22例患者HBeAg发生血清学转换,11例患者HBsAg转阴,2例发生HBsAg血清学转换。急性乙型肝炎患者CD3 细胞、CD4 细胞高于慢性乙型肝炎患者,但差异无统计学意义,而CD8 细胞则显著高于慢性乙型肝炎患者(t=2.382,P<0.05)。结论非细胞毒机制在急性乙型肝炎早期HBV DNA的清除中具有重要作用,特异性细胞免疫反应对彻底清除HBV DNA、防止感染慢性化起更重要的作用。     

Immune response to hepatitis B vaccine in patients with chronic hepatitis C infection: A systematic review and meta‐analysis

Hepatitis B virus and hepatitis C virus (HCV) co‐infection can add to the severity of hepatitis and the risks of liver cirrhosis and hepatocellular carcinoma. Whether chronic HCV infection decreases antibody response to hepatitis B vaccination is still controversial. We evaluate the influence of HCV infection on antibody response to hepatitis B vaccination by a systematic review of published works with a meta‐analysis of clinical trials. The random‐effects model of DerSimonian and Laird with heterogeneity and sensitivity analyses were used in this study. The end‐point of interest was the rate of patients showing seroconversion of antibody responses at completion of hepatitis B vaccination schedule among patients with chronic HCV infection versus healthy controls. We identified 11 studies involving 704 patients with HCV and 812 controls. Our results show a significant decrease in antibody seroconversion rates among patients with HCV versus healthy controls (pooled odds ratio = 0.17 [95% confidence interval, 0.11–0.28]). The P‐value was 0.21 for our test of study heterogeneity. Stratified analysis in subgroups of interest and sensitivity analysis did not meaningfully change our results. Our meta‐analysis showed patients with hepatitis C infection have a statistically significant lower rate of seroconversion in comparison to healthy controls, both in cirrhotic and non‐cirrhotic patients. Chronic HCV infection can decrease the immune response to a standard schedule of hepatitis B vaccination. Further studies are needed to investigate the optimum vaccination schedule for patients with chronic HCV infection.     

Suppression of hepatitis B virus replication mediated by hepatitis A‐induced cytokine production

Abstract: Background: Acute hepatitis A virus (HAV) infection can cause severe hepatitis especially in patients with underlying chronic liver disease. In patients with pre‐existing chronic hepatitis B (HBV) acute HAV infection can suppress HBV replication. The exact mechanism of HBV suppression during acute HAV infection is still a subject of debate. One mechanism may be the production of HAV infection‐induced cytokines leading to suppression of HBV replication and viral clearance. Aim: To evaluate cytokine production and HBV‐specific lympho‐proliferative responses (LPR) during acute HAV infection in a patient with chronic HBV infection‐clearing markers of active HBV replication. Design: Early detection of a case of acute HAV infection in an HBeAg‐positive, HBV DNA‐positive chronic HBV patient treated with lamivudine. Results: At the time of HAV infection a sharp peak in the gamma‐interferon (IFN‐γ) level occurred just before the rise in serum transaminase activity. This was subsequently followed by a decrease in HBV DNA and HBeAg below the limit of detection of the assay. However the HBV‐specific T‐cell response was not modified. After resolution of the acute HAV infection and withdrawal of antiviral therapy HBV replication relapsed. Conclusion: The sharp rise in IFN‐γ production mediated by the acute HAV infection may be pivotal in the suppression of HBV replication in chronic hepatitis B.     

DNA-based vaccination induces humoral and cellular immune responses against hepatitis B virus surface antigen in mice without activation of C-myc

AIM To develop a safe and effective DNA vaccine for inducing humoral and cellular immunological responses against hepatitis B virus surface antigen (HBsAg). METHODS BALB/c mice were inoculated with NV-HB/s, a recombinant plasmid that had been inserted S gene of hepatitis B virus genome and could express HBsAg in eukaryotes. HBsAg expression was measured by ABC immunohistochemical assay, generation of anti-HBs by ELISA and cytotoxic T lymphocyte (CTL), by MTT method, existence of vaccine DNA by Southern blot hybridization and activation of oncogene C-myc by in situ hybridization.RESULTS With NV-HB/s vaccination by intramuscular injection, anti-HBs was initially positive 2 weeks after inoculation while all mice tested were HBsAg positive in the muscles. The titers and seroconversion rate of anti-HBs were steadily increasing as time went on and were dose-dependent. All the mice inoculated with 100 μg NV-HB/ s were anti-HBs positive one month after inoculation, the titer was 1:1024 or more. The humoral immune response was similar induced by either intramuscular or intradermal injection. CTL activities were much stronger (45.26%) in NV-HB/s DNA immunized mice as compared with those (only 6%) in plasmaderived HBsAg vaccine immunized mice. Two months after inoculation, all muscle samples were positive by Southern-blot hybridization for NV-HB/s DNA detection, but decreased to 25%and all were undetectable by in situ hybridization after 6 months. No oncogene Cmyc activation was found in the muscle of inoculation site. CONCLUSION NV-HB/s could generate humoral and cellular immunological responses against HBsAg that had been safely expressed in situ by NV-HB/s vaccination.     

Effect of hepatitis B virus on steatosis in hepatitis C virus co‐infected subjects: A multi‐centre study and systematic review

It remains unclear whether hepatitis B virus (HBV) infection may modify the severity of viral steatosis in patients coinfected with chronic hepatitis C virus (HCV). We examined the influence of coinfection with HBV on prevalence of steatosis in chronic hepatitis C in a multi‐centre cohort of HBV‐HCV subjects, and by performing a systematic review and meta‐analysis of the literature. We centrally and blindly assessed steatosis prevalence and severity in a cohort of HBV‐HCV coinfected subjects compared to HCV and HBV monoinfected controls and we performed a systematic review of studies addressing the prevalence of steatosis in HBV‐HCV subjects compared to HCV controls. In the clinical cohort, we included 85 HBV‐HCV, 69 HBV and 112 HCV subjects from 16 international centres. There was no significant difference in steatosis prevalence between the HBV‐HCV and the HCV groups (33% vs 45%, P = .11). In subgroup analysis, lean HBV‐HCV subjects with detectable HBV DNA had less steatosis than lean HCV subjects matched for HCV viremia (15% vs 45%, P = .02). Our literature search identified 5 additional studies included in a systematic review. Overall, prevalence of steatosis > 5% was similar in HBV‐HCV infection compared to HCV (pooled odds ratio [OR] 0.91, 95% CI 0.53‐1.6) although there was significant heterogeneity (I² 69%, P = .007). In conclusion, although the prevalence of steatosis is similar in HBV‐HCV compared to HCV subjects, our analysis suggests that there may be an inhibitory effect of HCV‐induced steatogenesis by HBV in certain subgroups of patients.     

Low incidence of hepatitis B virus reactivation and subsequent hepatitis in patients with chronic hepatitis C receiving direct‐acting antiviral therapy

To determine the clinical characteristics of hepatitis B virus (HBV) reactivation in patients undergoing interferon‐free antihepatitis C virus (HCV) therapy, we examined HBV DNA in 25 HBV co‐infected patients and 765 patients with resolved HBV infection during and after treatment with direct‐acting antiviral agents (DAAs). Among those with HCV genotype 1, asunaprevir plus daclatasvir was administered to 160 patients, sofosbuvir (SOF) plus ledipasvir to 438 patients and paritaprevir plus ombitasvir and ritonavir to 25 patients. In total, 167 patients with genotype 2 were treated with SOF plus ribavirin. Three patients with an HBV DNA level ≥2000 IU/mL were treated with entecavir before anti‐HCV therapy, without reactivation of HBV. In 3 of 22 (12%) HBV surface antigen (HBsAg)‐positive patients with an HBV DNA level <2000 IU/mL, the viral load increased during treatment. However, hepatitis flare did not occur in these patients. There was no significant difference in clinical history between patients with and without HBV reactivation. Among 765 patients with resolved HBV infection, HBV reactivation occurred in 1 (0.1%) patient after initial resolution, whose HBV DNA level spontaneously decreased after DAA therapy. We compared anti‐HBs titres at baseline with those at post‐DAA therapy in 123 patients without HBsAg. There was no significant difference in anti‐HBs levels between the two points (P = .79). In conclusion, HBV reactivation was rare in HBsAg‐negative patients treated with DAA therapy. Additionally, hepatitis did not occur in HBV‐reactivated patients with a baseline HBV DNA level <2000 IU/mL before DAA therapy.