Xinyue Chen

A Randomized Controlled Phase IIb Trial of Antigen-Antibody Immunogenic Complex Therapeutic Vaccine in Chronic Hepatitis B Patients

Background The safety of the immune complexes composed of yeast-derived hepatitis B surface antigen (HBsAg) and antibodies (abbreviated as YIC) among healthy adults and chronic hepatitis B patients has been proved in phase I and phase IIa trial. A larger number of patients for study of dosage and efficacy are therefore needed. Methods and Principal Findings Two hundred forty two HBeAg-positive chronic hepatitis B patients were immunized with six injections of either 30 µg YIC, 60 µg of YIC or alum adjuvant as placebo at four-week intervals under code. HBV markers and HBV DNA were monitored during immunization and 24 weeks after the completion of immunization. The primary endpoint was defined as loss of HBeAg, or presence of anti-HBe antibody or suppression of HBV DNA, while the secondary endpoint was both HBeAg seroconversion and suppression of HBV DNA. Statistical significance was not reached in primary endpoints four weeks after the end of treatment among three groups, however, at the end of follow-up, HBeAg sero-conversion rate was 21.8%(17/78) and 9% (7/78) in the 60 µg YIC and placebo groups respectively (p = 0.03), with 95% confidence intervals at 1.5% to 24.1%. Using generalized estimating equations (GEEs) model, a significant difference of group effects was found between 60 µg YIC and the placebo groups in terms of the primary endpoint. Eleven serious adverse events occurred, which were 5.1%, 3.6%, and 5.0% in the placebo, 30 µg YIC and 60 µg YIC groups respectively (p>0.05). Conclusions Though statistical differences in the preset primary and secondary endpoints among the three groups were not reached, a late and promising HBeAg seroconversion effect was shown in the 60 µg YIC immunized regimen. By increasing the number of patients and injections, the therapeutic efficacy of YIC in chronic hepatitis B patients will be further evaluated. Trial Registration ChiCTR.org ChiCTR-TRC-00000022

MicroRNA-146a Feedback Suppresses T Cell Immune Function by Targeting Stat1 in Patients with Chronic Hepatitis B

More than 350 million people are chronically infected with hepatitis B virus, and dysfunctional T cell responses contribute to persistent viral infection and immunopathogenesis in chronic hepatitis B (CHB). However, the underlying mechanisms of T cell hyporesponsiveness remain largely undefined. Given the important role of microRNA-146a (miR-146a) in diverse aspects of lymphocyte function, we investigated the potential role and mechanism of miR-146a in regulating T cell immune responses in CHB. We found that miR-146a expression in T cells is significantly upregulated in CHB compared with healthy controls, and miR-146a levels were correlated with serum alanine aminotransaminase levels. Both inflammatory cytokines and viral factors led to miR-146a upregulation in T cells. Stat1 was identified as a miR-146a target that is involved in antiviral cytokine production and the cytotoxicity of CD4+ and CD8+ T cells. In vitro blockage of miR-146a in T cells in CHB greatly enhanced virus-specific T cell activity. Therefore, our work demonstrates that miR-146a upregulation in CHB causes impaired T cell function, which may contribute to immune defects and immunopathogenesis during chronic viral infection.

The 104‐week efficacy and safety of telbivudine‐based optimization strategy in chronic hepatitis B patients: A randomized, controlled study

An optimization strategy based on the Roadmap concept is supposed to improve the clinical outcomes of patients with suboptimal antiviral response. The aim of this study was to prove the concept with a multicenter, open‐label, randomized, controlled study. In all, 606 hepatitis B e antigen (HBeAg)‐positive, nucleos(t)ide‐naive chronic hepatitis B patients were randomized to the Optimize or Mono group. Patients in the Optimize group were treated with telbivudine for 24 weeks, after which those suboptimal responders with HBV DNA ≥300 copies/mL at week 24 received telbivudine plus adefovir until week 104, while the early virological responders continued telbivudine monotherapy. Patients in the Mono group received telbivudine monotherapy. All patients with telbivudine monotherapy had adefovir added if viral breakthrough developed. Sixty‐eight percent (204/300) of patients in the Optimize group had adefovir added due to suboptimal response. At week 104, compared to the Mono group, more patients in the Optimize group achieved HBV DNA <300 copies/ml (76.7% versus 61.2%, P < 0.001) with less genotypic resistance (2.7% versus 25.8%, P < 0.001). The rates of HBeAg seroconversion and alanine aminotransferase (ALT) normalization were comparable between the two groups (23.7% versus 22.1%; 80.7% versus 79.2%). For week 24 suboptimal responders, telbivudine plus adefovir showed an additive antiviral potency, with 71.1% achieving virological response at week 104 and only 0.5% developing genotypic resistance, compared with 46.6% who achieved virological response and 37.8% who developed genotypic resistance with telbivudine monotherapy. Both treatment regimens were well tolerated, with an observed persistent increase of the glomerular filtration rate. Conclusion: For suboptimal virological responders to telbivudine at week 24, adjusting the treatment strategy is recommended. Adding adefovir can benefit these patients with additive antiviral potency and low resistance without increased side effects. (Hepatology 2014;59:1283‐1292)

Extensive HLA-driven viral diversity following a narrow-source HIV-1 outbreak in rural China.

Obstacles to developing an HIV-1 vaccine include extensive viral diversity and lack of correlates of protective immunity. High mutation rates allow HIV-1 to adapt rapidly to selective forces such as antiretroviral therapy and immune pressure, including HIV-1-specific CTLs that select viral variants which escape T-cell recognition. Multiple factors contribute to HIV-1 diversity, making it difficult to disentangle the contribution of CTL selection without using complex analytical approaches. We describe an HIV-1 outbreak in 231 former plasma donors in China, where a narrow-source virus that had contaminated the donation system was apparently transmitted to many persons contemporaneously. The genetic divergence now evident in these subjects should uniquely reveal how much viral diversity at the population level is solely attributable to host factors. We found significant correlations between pair-wise divergence of viral sequences and HLA class I genotypes across epitope-length windows in HIV-1 Gag, reverse transcriptase, integrase, and Nef, corresponding to sites of 140 HLA class I allele-associated viral polymorphisms. Of all polymorphic sites across these 4 proteins, 24%-56% were sites of HLA-associated selection. These data confirm that CTL pressure has a major effect on inter-host HIV-1 viral diversity and probably represents a key element of viral control.

Liver transplantation in acute-on-chronic liver failure patients with high model for end-stage liver disease (MELD) scores: a single center experience of 100 consecutive cases

BACKGROUND Acute-on-chronic liver failure (ACLF) is a severe clinical condition for which liver transplantation (LT) is the only curative option. However, there are little published data on risk factors and outcomes of LT for ACLF. METHODS The objective of this study was to analyze preoperative, intraoperative, postoperative, and overall survival data on 100 consecutive cases with ACLF in order to try to determine for which patients LT are futile. RESULTS One hundred consecutive patients with pathology-confirmed ACLF who underwent LT from June 2004 to September 2012 were enrolled. The preoperative data showed that all patients were in a serious condition with a median high model for end-stage liver disease (MELD) score of 32, total bilirubin of 440.20 umol/L, international normalized ratio (INR) of 3.012, and at least one organ dysfunction as assessed by a Sequential Organ Failure Assessment (SOFA) score of ≥9. The patients had either deceased or a living donor LT with an overall mortality of 20%. The 1-, 3-, and 5-year cumulative survival rates were 76.8%, 75.6%, and 74.1%, respectively, and graft 1-, 3-, and 5-y accumulative survival rates were 73.3%, 72.1%, and 70.6%, respectively. However, the area under receiver operating characteristic of SOFA score, MELD score, as well as Child-Pugh score were 0.552, 0.547, and 0.547, respectively. CONCLUSIONS Both deceased and living donor LT are effective therapeutic options for patients with ACLF and the short- and long-term survival rates are encouraging. It is important to conduct more prospective and multi-center studies to define preoperatively which patients would benefit from LT.

Multilayered defense in HLA-B51-associated HIV viral control

Polymorphism in the HLA region of a chromosome is the major source of host genetic variability in HIV-1 outcome, but there is limited understanding of the mechanisms underlying the beneficial effect of protective class I alleles such as HLA-B57, -B27, and -B51. Taking advantage of a unique cohort infected with clade B’ HIV-1 through contaminated blood, in which many variables such as the length of infection, the infecting viral strain, and host genetic background are controlled, we performed a comprehensive study to understand HLA-B51–associated HIV-1 control. We focused on the T cell responses against three dominant HLA-B51–restricted epitopes: Gag327-345(NI9) NANPDCKTI, Pol743-751(LI9) LPPVVAKEI, and Pol283-289(TI8) TAFTIPSI. Mutations in all three dominant epitopes were significantly associated with HLA-B51 in the cohort. A clear hierarchy in selection of epitope mutations was observed through epitope sequencing. L743I in position 1 of epitope LI9 was seen in most B51+ individuals, followed by V289X in position 8 of the TI8, and then, A328S, in position 2 of the NI9 epitope, was also seen in some B51+ individuals. Good control of viral load and higher CD4+ counts were significantly associated with at least one detectable T cell response to unmutated epitopes, whereas lower CD4+ counts and higher viral loads were observed in patients who had developed escape mutations in all three epitopes or who lacked T cell responses specific to these epitope(s). We propose that patients with HLA-B51 benefit from having multiple layers of effective defense against the development of immune escape mutations.

Depletion of CD4+CD25+ regulatory T cells enhances natural killer T cell-mediated anti-tumour immunity in a murine mammary breast cancer model

Both invariant natural killer T (NK T) cells and CD4+CD25+ T regulatory cells (Tregs) regulate the immune system to maintain homeostasis. In a tumour setting, NK T cells activated by α‐galactosylceramide (α‐GalCer) execute anti‐tumour activity by secreting cytokines. By contrast, Tregs intrinsically suppress antigen‐specific immune responses and are often found to be elevated in tumour patients. In this study, we have shown that Tregs regulate NK T cell function negatively in vitro, suggesting a direct interaction between these cell types. In a murine mammary tumour model, we demonstrated that administration of either α‐GalCer or anti‐CD25 antibody alone markedly suppressed tumour formation and pulmonary metastasis, and resulted in an increase in the survival rate up to 44% (from a baseline of 0%). When treatments were combined, depletion of Tregs boosted the anti‐tumour effect of α‐GalCer, and the survival rate jumped to 85%. Our results imply a potential application of combining Treg cell depletion with α‐GalCer to stimulate NK T cells for cancer therapy.

Potent hepatitis B surface antigen response to treatment of hepatitis-B-e-antigen-positive chronic hepatitis B with α-interferon plus a nucleos(t)ide analog.

Background and Aim:  Hepatitis B surface antigen (HBsAg) clearance is the closest cure outcome in hepatitis B. The goal of this study was to investigate clinical features in chronic hepatitis B patients achieving seroconversion of HBsAg after treatment with α‐interferon (IFN‐α) and a nucleos(t)ide analog.

Central Memory CD4 Cells Are an Early Indicator of Immune Reconstitution in HIV/AIDS Patients with Anti-Retroviral Treatment

The number of central memory cells among the CD4+ T cells and the of activation of CD8+ T cells is believed to be a better indicator of immune restoration in patients on antiretroviral therapy (ART) than the absolute numbers of CD4+ and CD8+ T cells alone. In the current study, we investigated the changes in the CD4+ T cell subsets and their association with immune reconstitution and immune activation at early stages of ART. A prospective study was performed in 21 asymptomatic treatment-naive HIV-infected patients with CD4+ T cells less than 350 cells/μl. Blood samples were evaluated at base line, and at 2, 4, 8 and 12 weeks’ post antiretroviral therapy (ART). A biphasic increase of CD4+ T cells, central memory CD4 cells (CD4 CM) and CD4 naïve cells were observed after ART, with a rapid increase before week 4. Change in CD4 CM at week 4 positively correlated with the change in CD4+ T cells at weeks 12 post ART, and negatively correlated with the change in CD8+CD38+ T cells at weeks 12 post ART. We conclude that CD4 CM cells are a major contributor to early immune reconstitution in treatment-naive HIV-infected patients with delayed ART, and might be an early indicator for immune reconstitution.

HIV burden in men who have sex with men: a prospective cohort study 2007–2012

We conducted a prospective cohort study among HIV-negative MSM aged 18 years or older between 2007 and 2012 in Beijing, China to measure the rates of incident HIV and identify risk factors for infection. Among 5,800 participants evaluated at enrollment, we identified 486 prevalent cases of HIV (8.4%). Among the 3,625 enrollees who were HIV-negative at enrollment and completed at least one follow-up interview, we identified 440 incident cases of HIV in the follow up period: this constituted an HIV incidence rate of 7.1 per 100 person-years (95% CI: 6.4–7.7). Early treatment of syphilis may have significantly reduced risk of HIV infection (RR: 1.45, 95% CI: 1.11–1.93), while MSM presenting perfect compliance in the cohort did not show reduction in HIV infection. Our study suggested that HIV incidence has been remained high in this sample of Chinese MSM during the intensive preventive intervention, suggesting that we need to find new strategies to prevent HIV infection in this population.