Transient restoration of anti-viral T cell responses induced by lamivudine therapy in chronic hepatitis B

BACKGROUND/AIMS: Lamivudine therapy in patients with chronic hepatitis B can induce the recovery of antiviral T cell responses. It is unknown whether the recovery of T cell responsiveness is long-lasting and persists throughout the treatment and whether the elevation of viremia which follows therapy withdrawal can restore a condition of T cell unresponsiveness. METHODS: Frequency and function of circulating hepatitis B virus (HBV)-specific CD4 and CD8 cells from 12 hepatitis e surface antigen + patients with chronic hepatitis B were studied longitudinally before, during and after lamivudine therapy by intracellular cytokine staining, proliferation and cytotoxicity assays against HBV proteins and peptides. CD4-mediated responses were analyzed in all patients, whereas CD8 cells were studied in 6 HLA-A2+ patients. RESULTS: HBV-specific CD4 and CD8 reactivity showed a bi-phasic behavior under lamivudine therapy with an early enhancement of T cell frequency and intensity of responses followed by a persistent decline starting from the 5th to 6th month of treatment. CONCLUSIONS: Since restoration of HBV-specific T cell reactivity is only transient, our study indicates that therapeutic stimulation of HBV-specific T cell responses to complement lamivudine treatment should be done early after the initiation of lamivudine. Moreover, the transient nature of the immune reconstitution may represent a favorable condition for virus reactivation once lamivudine therapy is withdrawn.     

Lamivudine treatment can overcome cytotoxic T-cell hyporesponsiveness in chronic hepatitis B: new perspectives for immune therapy

The hepatitis B virus (HBV) cytotoxic T lymphocyte (CTL) response in patients with chronic HBV infection is generally weak or totally undetectable. This inability to mount protective CTL responses is believed to be a crucial determinant of viral persistence, and its correction represents an important objective of immune therapies for chronic hepatitis B. However, amplification of CTL responses in vivo may be ineffective if HBV-specific CD8 cells are either absent or nonresponsive to exogenous stimulation. In this study, we asked whether antiviral treatments able to inhibit viral replication and to reduce viral and antigen load can successfully reconstitute CTL responses creating the appropriate conditions for their therapeutic stimulation. For this purpose, the HBV-specific CTL response before and during lamivudine therapy was studied longitudinally in 6 HLA-A2-positive patients with HBeAg+ chronic hepatitis B. Both HBV-specific cytotoxic T cell activity measured by chromium release assay on peptide stimulation in vitro and CD8+ T cell frequency measured ex vivo by HLA-A2/peptide tetramer staining were significantly augmented by lamivudine therapy. This enhancement followed the reconstitution of CD4 reactivity and the decline of viral load induced by therapy. Our study shows that lamivudine treatment in chronic hepatitis B can restore CTL reactivity, making CTL susceptible to exogenous stimulation. This effect may enhance the probability that T cell-based immune therapies delivered after lamivudine treatment can successfully reconstitute a protective CTL response able to cure chronic HBV infection.     

Antiviral CD8-mediated responses in chronic HCV carriers with HBV superinfection

Hepatitis B virus (HBV) superinfection in chronic hepatitis C represents a natural model to investigate whether or not hepatitis C virus (HCV) can influence priming and maturation of antiviral T cells; whether or not HBV superinfection, which is known to determine control of HCV replication, can restore HCV-specific T cell responsiveness; and whether or not cytokines stimulated by HBV infection can contribute to HCV control. To address these issues, the function of CD8 cells specific for HBV and HCV was studied longitudinally in two chronic HCV patients superinfected with HBV. Patients with acute hepatitis B were also examined. Frequency and function of HBV tetramer+ CD8 cells were comparable in patients acutely infected with HBV with or without chronic HCV infection. HBV-specific CD8 cell function was efficiently expressed irrespective of serum HCV-RNA levels. Moreover, fluctuations of HCV viremia at the time of HBV superinfection were not associated with evident changes of CD8 responsiveness to HCV. Finally, no correlation was found between serum levels of interferon alpha, interleukin (IL)-12, IL-10, or IL-18 and control of HCV replication. In conclusion, HCV did not affect the induction of primary and memory HBV-specific CD8 responses. HCV-specific CD8 responses were undetectable when HCV-RNA was negative, showing that inhibition of HCV replication in the setting of a HBV superinfection was not sufficient to induce a restoration of CD8 reactivity against HCV.     

Tumor necrosis factor alpha inhibits the suppressive effect of regulatory T cells on the hepatitis B virus-specific immune response

Chronicity of hepatitis B virus (HBV) infection is characterized by a weak immune response to the virus. CD4+CD25+ regulatory T cells (Treg) are present in increased numbers in the peripheral blood of chronic HBV patients, and these Treg are capable of suppressing the HBV-specific immune response. The aim of this study was to abrogate Treg-mediated suppression of the HBV-specific immune response. Therefore, Treg and a Treg-depleted cell fraction were isolated from peripheral blood of chronic HBV patients. Subsequently, the suppressive effect of Treg on the response to HBV core antigen (HBcAg) and tetanus toxin was compared, and the effect of exogenous tumor necrosis factor alpha (TNF-alpha), interleukin-1-beta (IL-1beta), or neutralizing antibodies against interleukin-10 (IL-10) or transforming growth factor beta (TGF-beta) on Treg-mediated suppression was determined. The results show that Treg of chronic HBV patients had a more potent suppressive effect on the response to HBcAg compared with the response to tetanus toxin. Neutralization of IL-10 and TGF-beta or exogenous IL-1beta had no effect on Treg-mediated suppression of the anti-HBcAg response, whereas exogenous TNF-alpha partially abrogated Treg-mediated suppression. Preincubation of Treg with TNF-alpha demonstrated that TNF-alpha had a direct effect on the Treg. No difference was observed in the type II TNF receptor expression by Treg from chronic HBV patients and healthy controls. CONCLUSION: Treg-mediated suppression of the anti-HBV response can be reduced by exogenous TNF-alpha. Because chronic HBV patients are known to produce less TNF-alpha, these data implicate an important role for TNF-alpha in the impaired antiviral response in chronic HBV.     

Incubation phase of acute hepatitis B in man: dynamic of cellular immune mechanisms

After hepatitis B virus (HBV) infection, liver injury and viral control have been thought to result from lysis of infected hepatocytes by virus-specific cytotoxic T cells. Patients are usually studied only after developing significant liver injury, and so the viral and immune events during the incubation phase of disease have not been defined. During a single-source outbreak of HBV infection, we identified patients before the onset of symptomatic hepatitis. The dynamics of HBV replication, liver injury, and HBV-specific CD8+ and CD4+ cell responses were investigated from incubation to recovery. Although a rise in alanine transaminase (ALT) levels was present at the time of the initial fall in HBV-DNA levels, maximal reduction in virus level occurred before significant liver injury. Direct ex vivo quantification of HBV-specific CD4+ and CD8+ cells, by using human leukocyte antigen (HLA) class I tetramers and intracellular cytokine staining, showed that adaptive immune mechanisms are present during the incubation phase, at least 4 weeks before symptoms. The results suggest that the pattern of reduction in HBV replication is not directly proportional to tissue injury during acute hepatitis B in humans. Furthermore, because virus-specific immune responses and significant reductions in viral replication are seen during the incubation phase, it is likely that the immune events central to viral control occur before symptomatic disease.     

Kinetics of peripheral hepatitis B virus-specific CD8+ T cells in patients with onset of viral reactivation

Background

Patients with resolved hepatitis B virus (HBV) infection undergoing chemotherapy or immunosuppressive therapy are potentially at risk of HBV reactivation. However, it remains unclear how liver disease develops after HBV reactivation. To compare the host immune response against HBV, we performed immunological analyses of six HBV reactivation patients.

Methods

The numbers of peripheral HBV-specific CD8⁺ T cells were investigated longitudinally in six HLA-A2- and/or A24-positive patients with HBV reactivation. In addition, 34 patients with resolved HBV, 17 patients with inactive chronic hepatitis B (ICHB), 17 patients with chronic hepatitis B (CHB) and 12 healthy controls were analyzed. The number and function of HBV-specific CD8⁺ T cells were assessed by flow cytometry using tetramer staining and intracellular IFN-γ production. Furthermore, the numbers of CD4⁺CD25⁺ or CD4⁺Foxp3⁺ T cells and serum inflammatory cytokine levels were analyzed.

Results

The frequency of HBV-specific CD8⁺ T cells was significantly increased in HBV reactivation patients compared with ICHB and CHB patients. In addition, the number of HBV-specific CD8⁺ T cells was increased in resolved HBV patients compared with ICHB patients. PD-1 expression was decreased in HBV reactivation patients compared with ICHB and CHB patients. The numbers of HBV-specific CD8⁺ T cells and CD4⁺CD25⁺ or CD4⁺Foxp3⁺ T cells were negatively correlated following onset of HBV reactivation.

Conclusions

During HBV reactivation, the frequency of HBV-specific CD8⁺ T cells increased even though the administration of immunosuppressive drugs and interactions with CD4⁺ regulatory T cells may be important for the onset of liver disease.     

Depletion of CD25^＋CD4^＋T cells （Tregs） enhances the H BV-specific CD8^＋ T cell response primed by DNA immunization

AIM: Persistent hepatitis B virus (HBV) infection is characterized by a weak CD8+ T cell response to HBV. Immunotherapeutic strategies that overcome tolerance and boost these suboptimal responses may facilitate viral clearance in chronically infected individuals. Therefore, we examined whether CD25+CD4+ regulatory T (Treg) cells might be involved in a inhibition of CD8+T cell priming or in the modulation of the magnitude of the 'peak' antiviral CD8+ T cell response primed by DNA immunization. METHODS: B10.D2 mice were immunized once with plasmid pCMV-S. Mice received 500 μg of anti-CD25 mAb injected intraperitoneally 3 d before DNA immunization to deplete CD25+ cells. Induction of HBV-specific CD8+ T cells in peripheral blood mononuclear cells (PBMCs) was measured by S28-39 peptide loaded DimerX staining and their function was analyzed by intracellular IFN-γ staining. RESULTS: DNA immunization induced HBV-specific CD8+ T cells. At the peak T cell response (d 10), 7.1±2.0% of CD8+ T cells were HBV-specific after DNA immunization, whereas 12.7±3.2% of CD8+ T cells were HBV-specific in Treg-depleted mice, suggesting that DNA immunization induced more antigen-specific CD8+ T cells in the absence of CD25+ Treg cells (n = 6, P<0.05). Similarly, fewer HBV specific memory T cells were detected in the presence of these cells (1.3±0.4%) in comparison to Treg-depleted mice (2.6±0.9%) on d 30 after DNA immunization (n - 6, P<0.01). Both IFN-γ production and the avidity of the HBV-specific CD8+ T cell response to antigen were higher in HBV-specific CD8+ T cells induced in the absence of Treg cells. CONCLUSION: CD25+ Treg cells suppress priming and/or expansion of antigen-specific CD8+ T cells during DNA immunization and the peak CD8+ T cell response is enhanced by depleting this cell population. Furthermore, Treg cells appear to be involved in the contraction phase of the CD8+ T cell response and may affect the quality of memory T cell pools. The elimination of Treg cells or their inhibition may be important in immunotherapeutic strategies to control HBV infection by inducing virus-specific cytotoxic T lymphocyte responses in chronically infected subjects.     

HBV感染者外周血CD4^＋CD25^＋调节性T细胞的表达水平及临床意义

目的比较CD4^＋CD25^＋FoxP3^＋和CD4^＋CD25^＋CD127^-/low两种设门方法对CD4^＋CD25^＋调节性T细胞（Treg）细胞的界定效果,并探讨HBV感染者外周血中Treg水平的表达及其临床意义。方法选择慢性乙型肝炎患者52例,HBV携带者24例,非活动性HBsAg携带者24例,正常对照者25例,采用CD4^＋CD25^＋CD127^-/low设门方法用流式细胞仪进行检测,其中正常对照组和21例慢性乙型肝炎患者同时采用CD4^＋CD25^＋FoxP3^＋设门进行检测并分析。结果采用CD4^＋CD25^＋CD127^-/low设门方法检测外周血Treg与CD4^＋CD25^＋FoxP3^＋设门方法在正常组和患者组均呈正相关（r=0.506,P〈0.05;r=0.556,P〈0.01）。以CD4^＋CD25^＋CD127^-/low设门检测慢性乙型肝炎患者组、HBV携带者组、非活动性HBsAg携带者组和正常对照组外周血Treg的水平分别为（10.65±2.86）%、（8.56±2.01）%、（8.75±3.04）%和（7.33±1.17）%。慢性乙型肝炎患者组明显高于其他三组（P〈0.01）,慢性HBV携带者组明显高于对照组（P〈0.05）,非活动性HBsAg携带者组与对照组之间差异无统计学意义。慢性乙型肝炎患者及慢性HBV携带者Treg表达水平与HBV病毒载量之间均无相关,慢性乙型肝炎患者Treg表达水平与ALT之间无相关,HBeAg阳性患者组和HBeAg阴性患者组的Treg表达水平差异无统计学意义。结论 CD4^＋CD25^＋CD127^-/low设门方法检测外周血Treg与CD4^＋CD25^＋FoxP3^＋设门方法有较好的相关性,而前者更为简单、实用。Treg在慢性乙型肝炎患者、慢性HBV携带者中明显增高,提示Treg在乙型肝炎慢性化机制中发挥重要作用。     

HBcAg-pulsed dendritic cell vaccine induces Th1 polarization and production of hepatitis B virus-specific cytotoxic T lymphocytes

Aim:  Dendritic cells (DCs) pulsed with HBsAg efficiently reverse the immune tolerance to hepatitis B virus (HBV) and induce HBV-specific cytotoxic T lymphocyte (CTL) responses in transgenic mice and healthy volunteers. However, it is not clear whether HBV core antigen (HBcAg)-pulsed DCs can effectively induce CD4⁺ helper T cells polarization into Th1, which contribute to the induction and maintenance of HBV-specific CD8⁺ T cells in chronic hepatitis B (CHB) patients. To address this issue, we conducted this study and investigated whether HBcAg-pulsed DCs could polarize Th1 cells and induce an HBcAg-specific CTL response.
Methods:  HBcAg-pulsed DCs were generated from 21 CHB patients. The capacity of the HBcAg-pulsed DC vaccine to stimulate CD4⁺ and CD8⁺ T cells to produce IFN-γ and IL-4 was estimated by intercellular cytokine staining, and the HBcAg-pulsed DCs derived from 10 humam leucocyte antigen (HLA)-A2⁺ CHB patients were tested for the induction of HBV-specific CTLs from autologous T cells by pentamer staining. The cytotoxicity of these CTLs was evaluated in vitro by flow cytometry.
Results:  The HBcAg-pulsed DCs derived from CHB patients exhibited a stronger capacity to stimulate autologous CD4⁺ and CD8⁺ T cells to release IFN-γ rather than IL-4, which could induce HBV core 18-27 specific CTLs, suggesting a specific cytotoxicity against T2 cells that had been loaded with the HBV core 18-27 peptide in vitro .
Conclusion:  HBcAg-pulsed DC vaccine derived from CHB patients efficiently induced autologous T cell polarization to Th1 and generation of HBV core 18-27 specific CTLs.     

Programmed death-1 expression is associated with the disease status in hepatitis B virus infection

AIM： TO define the potential role of programmed death-i/programmed death-ligand （PD-1/PD-L） pathway in different hepatitis B virus （HBV） infection disease status; we examined the expression of PD-1 on antigen specific CD8＋T cells in peripheral blood of patients with chronic hepatitis B （CriB） and acute exacerbation of hepatitis B （AEHB） infection.
METHODS： The PD-1 level on CD8＋ T lymphocytes and the number of HBV specific CD8＋ T lymphocytes in patients and healthy controls （HCs） were analyzed by staining with pentameric peptide-human leukocyte antigen2 （HLA2） complexes combined with flow cytometry. Real-time quantitative polymerase chain reaction （PCR） was used to measure the serum HBV- DNA levels.
RESULTS： The level of PD-1 expression on total CD8＋ T cells in CHB patients （13.86% ± 3.38%） was significantly higher than that in AEHB patients （6.80%± 2.19%, P 〈 0.01） and healthy individuals （4.63% ± 1.23%, P 〈 0.01）. Compared to AEHB patients （0.81% ± 0.73%）, lower frequency of HBV-specific CD8＋ T cells was detected in chronic hepatitis B patients （0.37% ± 0.43%, P 〈 0.05）. There was an inverse correlation between the strength of HBV-specific CD8＋ T-cell response and the level of PD-1 expression. Besides, there was a significant positive correlation between HBV viral load and the percentage of PD-1 expression on CD8＋ T cells in CriB and AEHB subjects （R = 0.541, P 〈 0.01）. However, PD-1 expression was not associated with disease flare-ups as indicated by alanine aminotransferase （ALT） levels （R = 0.066, P 〉 0.05）.
CONCLUSION： Our results confirm previous reports that HBV specific CD8＋T-cell response in the peripheral blood is more intense in patients with AEHB than in chronic hepatitis B wlth persistent viral infection. Moreover, there is a negative correlation between the level of PD-1 and the intensity of virus specific CD8＋ T cell response.     

Direct ex vivo analysis of hepatitis B virus-specific CD8(+) T cells associated with the control of infection

BACKGROUND & AIMS: Cytotoxic T cells have been suggested to be responsible for lysis of hepatitis B virus (HBV)-infected hepatocytes and control of virus infection. The frequency, kinetics, phenotype, and capacity for clonal expansion of circulating HBV-specific CD8 cells were analyzed directly in patients with acute HBV infection to clarify their pathogenetic role. METHODS: Three HLA-A2 peptide tetramers able to visualize HBV core, envelope, and polymerase epitope-specific cytotoxic T lymphocytes were synthesized and used for flow cytometric analysis of antigen-specific populations. RESULTS: Tetramer-positive cells specific for the core 18-27 epitope were found at a higher frequency than those specific for polymerase 575-583 and envelope 335-343 epitopes in most patients with acute HBV. The number of HBV-specific CD8 cells was highest during the clinically acute stage of infection and decreased after recovery. These cells expressed an activated phenotype and had an impaired capacity to expand in vitro and to display cytolytic activity in response to peptide stimulation. Recovery of these functions was observed when the frequency of specific CD8 cells decreased, coincident with a progressive decrease in their expression of activation markers. CONCLUSIONS: This study provides the first ex vivo evidence that the highest frequency of circulating HBV-specific CD8 cells coincides with the clinically acute phase of hepatitis B. These cells exhibit an activated phenotype with limited further proliferative capacity that is restored during recovery.     

Regulatory T cells contribute to the impaired immune response in patients with chronic hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is characterized by a weak immune response to HBV. Regulatory T cells (T(reg)) can suppress the function of effector T cells and may thus be key players in this impaired immune response. Changes in the functionality or number of T(reg) could explain the decreased antiviral response in chronic HBV patients. To investigate the role of T(reg) in chronic HBV infection, we compared the proportional frequency and functionality of T(reg) in peripheral blood of 50 chronic HBV patients, 23 healthy controls, and 9 individuals with a resolved HBV infection. A higher percentage of T(reg), defined as CD4, CD25, CD45RO, and cytotoxic T-lymphocyte-associated antigen 4-positive cells, was detected within the population of CD4(+) cells in peripheral blood of chronic HBV patients compared with healthy controls and individuals with a resolved HBV infection. Accordingly, chronic HBV patients displayed a higher FoxP3 messenger RNA level than healthy controls. Depletion of CD25(+) cells from peripheral blood mononuclear cells (PBMC) of chronic HBV patients resulted in an enhanced proliferation after stimulation with HBV core antigen. Reconstitution of these depleted PBMC with CD4(+)CD25(+) T(reg) resulted in a dose-dependent reduction of both HBV-specific proliferation and interferon gamma production. In conclusion, chronic HBV patients harbor an increased percentage of T(reg) in peripheral blood compared with controls. T(reg) have an immunosuppressive effect on HBV-specific T helper cells. The presence of HBV-specific T(reg) could contribute to an inadequate immune response against the virus, leading to chronic infection.     

慢性乙型肝炎患者浆样树突状细胞体外诱导CD4+CD25+调节性T细胞的研究

目的 观察慢性乙型肝炎患者,乙型肝炎恢复者和健康人浆样树突状细胞(pDCs)体外诱导CD4+CD25+调节性T细胞(CD4+CD25+Treg)能力的差异,为阐明HBV感染慢性化的机制奠定基础.方法 采用免疫磁珠分离法体外分离46例慢性乙型肝炎患者,10例乙型肝炎恢复者和25名健康人外周血单个核细胞中pDCs,并将其分别与健康人CD4+CD45RA+初始T细胞共培养.采用HBcAg或破伤风毒素对去除CD25+细胞的外周血单个核细胞进行增殖刺激后,使用流式细胞仪及RT-PCR对pDCs-T共培养细胞中CD4+CD25+Treg的数量、表型及FOXP3基因表达情况进行测定;采用酶联免疫吸附法对共培养细胞上清液中的白细胞介素-10和转化生长因子β1进行了进一步检测.两组数据比较采用Mann Whitney U-test.结果 当细胞增殖刺激物为HBcAg时,细胞增殖幅度慢性乙型肝炎患者组为(7999.36±374.74)cpm,乙型肝炎恢复者组为(11 282.56±1174.46)cpm和健康人组为(12 304.58±1462.81)cpm,慢性乙型肝炎患者组细胞增殖幅度明显小于乙型肝炎恢复者组和健康人组,U=0～22.0,P值均<0.05·乙型肝炎恢复者组和健康人组间增殖幅度差异无统计学意义.当增殖刺激物为破伤风毒素时,细胞增殖幅度与阳性对照组之间,差异无统计学意义.CD4+CD25+Treg比例慢性乙型肝炎患者组为5.99%±1.85%,乙型肝炎恢复者组为3.04%±0.79%,健康人组为3.01%±1.53%,慢性乙型肝炎患者组中韵CD4+CD25+Treg比例明显高于乙型肝炎恢复者组和健康人组,U=6.0～71.5,P值均<0.05.3组人群pDCs-T共培养细胞的CD4+CD25+T细胞均检测到Fox p3 RNA,而在CD4+CD25 T细胞中,均未检测到Fox p3RNA.3组人群pDCs-T共培养细胞实验组上清液的白细胞介素-10和转化生长因子β1含量均明显高于阳性对照组.结论 pDCs以诱导CD4+CD25+Treg形式参与了乙型肝炎的慢性化.     

从Th1/Th2、Treg/Th17之间的平衡研究轻、中度慢性乙型肝炎患者CD4~+T淋巴细胞的免疫失衡状态

目的从Th17及其相关细胞因子与Th1、Th2、Treg的相互关系,探讨轻、中度CHB患者CD4~+T淋巴细胞的整体免疫失衡状态。方法选择轻、中度CHB患者,与健康志愿者进行比较,观察其外周血各免疫细胞(Th17、Th1、Th2、Treg、Th1/Th2、Treg/Th17)、相关细胞因子(IL-17、IL-6、TGF-β、IFN-γ、IL-4)、主要效应分子(穿孔素、颗粒酶B)和核转录因子(孤独核受体RORγt、Foxp3等)的变化及其相互关系。结果与健康志愿者相比,CHB患者CD8~+T淋巴细胞比例更高,CD4~+/CD8~+比例显著下降,差异有统计学意义(P0.01);与健康志愿者相比,CHB患者Th1细胞比例更高,Th1/Th2显著升高,差异有统计学意义(P0.01);与健康志愿者相比,CHB患者Th17细胞比例更高,Treg/Th17比例显著下降,差异有统计学意义(P0.01);与健康志愿者相比,CHB患者穿孔素和颗粒酶B的表达更高,差异有统计学意义(P0.01);与健康志愿者相比,CHB患者FOXP3、IL17mRNA和RORγt的表达差异无统计学意义(P0.05);与健康志愿者相比,CHB患者TGF-B1、IL-6、IL-17显著增高,差异有统计学意义(P0.01);IFN-γ和IL-4的表达差异无统计学意义(P0.05)。结论轻、中度CHB患者在免疫细胞及其相关细胞因子、效应分子等各环节,尤其是Treg/Th17比例,均处于严重的免疫失衡状态。     

Longitudinal fluctuations in PD1 and PD-L1 expression in association with changes in anti-viral immune response in chronic hepatitis B

ABSTRACT: BACKGROUND: Controversy exists regarding the role of PD1 and its ligand PD-L1 in chronic hepatitis B infection. In some studies, persistent HBV infection has been attributed to high levels of PD-1 and PD-L1 expression on HBV-specific T-cells and antigen-presenting cells (APCs) respectively. Other studies revealed that the up-regulation of PD-1 and PD-L1 during an acute inflammation phase is required to offset increasing positive co-stimulatory signals to avoid severe damage by an over-vigorous immune response. METHODS: Fifteen chronic hepatitis B patients, with inflammatory flare episode, were recruited prospectively. Based on serum HBV-DNA, HBsAg load, and ALT values, inflammatory flare episode were divided into initial, climax, decline and regression phase. Blood sample and liver biopsy tissues from each individual were taken in these 4 phases respectively. Circulating and intra-hepatic PD1 and PD-L1 expression levels were monitored throughout the inflammatory flare episode by flow cytometry and immunostaining and these expression levels were related to the HBV-specific T-cell changes, expression of pro-inflammatory cytokines, HBV-DNA replication and HBV antigen load. RESULTS: ]The levels of PD-1 and PD-L1 expressions were significantly up-regulated in the inflammation ascending phase, initial and climax period and in parallel with HBV-specific colon expansion. It showed increasing the level of serum ALT and decreasing the HBV-DNA loads. As the level of inflammation reduced, the circulating and intra-hepatic PD1 and circulating PD-L1 decreased progressively in concordance with serum ALT, HBV-DNA and HBsAg loads decreased except intra-hepatic PD-1 expression. Intra-hepatic PD-L1 expression did not decrease significantly during the regression phase of inflammation compared to that in prior period. The intra-hepatic PD-L1 expression remained relatively on higher level when serum HBV-DNA load and ALT decreased to approximately normal range. CONCLUSION: The relatively high level of intra-hepatic PD-L1 expression during the inflammatory regression period may contribute to constitute an immunosuppressive microenvironment, which facilitate persistent HBV infection via the inhibition of HBV-specific T cell clonal expansion.     

FoxP3+ Regulatory T Cells in Peripheral Blood of Patients with Epithelial Ovarian Cancer

Background: Ovarian cancer is the fifth leading cause of death from malignancy in women. CD4 +CD25+FoxP3+ regulatory T (Treg) cells are a subset of T lymphocytes with great inhibitory impact on immune response. Objectives: To investigate the percentage of CD4 +CD25+FoxP3+ regulatory T cells in the peripheral blood of the Iranian patients with epithelial ovarian cancer compared to healthy women and to evaluate the correlation of the Treg cell percentage with clinicopathological characteristics including cancer stage and CA-125 serum level. Methods: Seventeen women with epithelial ovarian cancer and 20 healthy subjects were enrolled in the study. Peripheral blood mononuclear cells were stained at the surface, for CD4 and CD25 molecules, followed by fixation, permeabilization and intracellular staining for FoxP3 molecule. After processing and flowcytometry analysis, prevalence of Treg cells was determined as the percentages of CD25 +FoxP3+ cells among CD4+ lymphocytes. Results: Despite no difference in the percentage of total CD4+ lymphocytes, analysis indicated that Treg cell percentage was significantly higher in ovarian cancer patients than controls (5.7 ± 3.1% versus 2.8 ± 1.4%, p=0.002). A trend toward higher Treg cells was observed in higher stages of ovarian cancer (III+IV) in comparison to lower stages (I+II) (6.5 ± 3.2% vs. 4.44 ± 2.7%, p=0.2). Higher percentage of Treg cells was also observed in the patients with high CA125 (CA-125 >100 U/mL) in comparison to those with low CA-125 serum level (CA-125 ≤100 U/mL) although the difference was not significant (6.44 versus 4.18%, p=0.19). Conclusion: Increased frequency of Tregs in ovarian cancer might participate in immune suppression in these patients. The findings collectively suggest the likely impact of Treg cell–targeted immunotherapy in ovarian cancer.     

T‐cell responses to hepatitis B splice‐generated protein of hepatitis B virus and inflammatory cytokines/chemokines in chronic hepatitis B patients. ANRS study: HB EP 02 HBSP‐FIBRO

Summary. A new hepatitis B virus (HBV) protein, hepatitis B splice‐generated protein (HBSP), has been detected in liver biopsy specimens from patients with chronic active hepatitis. The aim of this study was to characterize the phenotype and functions of peripheral HBSP‐specific T cells and to determine whether these T‐cell responses may be implicated in liver damage or viral control. Two groups of patients were studied: HBV‐infected patients with chronic active hepatitis and HBV‐infected patients who were inactive carriers of hepatitis B surface antigen. HBSP‐specific T‐cell responses were analysed ex vivo and after in vitro stimulation of peripheral blood mononuclear cells. Soluble cytokines and chemokines were analysed in sera and in cell culture supernatants. Few HBSP‐ or capsid‐specific T‐cell responses were detected in patients with chronic active hepatitis whereas frequency of HBV‐specific T cells was significantly higher in inactive carrier patients. HBSP activated CD8+ and CD4+ T cells that recognized multiple epitopes and secreted inflammatory cytokines. The IL‐12 level was significantly lower in sera from asymptomatic carrier patients compared to patients with chronic active hepatitis. IL‐12 and IP‐10 levels in the sera were significantly and independently correlated with both alanine amino transferase and HBV DNA levels. Our results show that the HBSP protein activates cellular immune responses in HBV‐infected patients but has probably no prominent role in liver damage. The pattern of cytokines and chemokines in sera was linked to HBV viral load and was consistent with the level of inflammation during chronic hepatitis.     

The impact of HBV-DNA fluctuations on virus-specific CD8+ T cells in HBeAg+ chronic hepatitis B patients treated with a steroid and lamivudine

Restoration of anti-viral immune response may be a requisite for sustained virological response to treatment in chronic hepatitis B patients. Over a 13-month period, we examined the dynamics of hepatitis B virus (HBV)-specific CD8+ cells in six human leucocyte antigen (HLA)-A2+ hepatitis B e antigen (HBeAg)+ 'immunotolerant' chronic hepatitis B patients treated sequentially with corticosteroid and lamivudine. Our results show that the combination treatment did not result in a sustained restoration of anti-viral specific CD8+ cells in five of the six patients studied. However, HBV-specific CD8+ cells, despite being severely compromised, were not totally deleted. Paradoxically, steroid treatment was not associated with inhibition but with a minimal increase of the HBV-specific CD8 response, and we observed that nucleocapsid-specific CD8 responses were not rescued by stable and prolonged inhibition but became detectable after rapid rebounds of HBV replication. In most patients, the transient and minimal restoration of HBV-specific immunity was not associated with clinical benefits. Our results describe a dynamic relationship between HBV-specific CD8+ cells and HBV-DNA values, that could potentially be used for a better design of HBV treatment in HBeAg+ 'immunotolerant' chronic hepatitis B patients.     

慢性乙型肝炎患者血清转化生长因子β1与CD4~+CD25~+Foxp3~+调节性T淋巴细胞的关系

目的 调查慢性乙型肝炎患者转化生长因子β1(TGF β1)与CD4~+CD25~+Foxp3~+调节性T淋巴细胞异常的关系.方法 将实验对象分为慢性乙型肝炎(CHB)患者、无症状HBV携带者(AsC)、乙型肝炎恢复者、正常人对照4组.通过流式细胞术分析外周CD4~+CD25~+Foxp3~+调节性T淋巴细胞的表型和频率以及实时荧光定量PCR分析Foxp3表达水平;并通过酶联免疫吸附法检测血清中TGF β1水平.根据数据不同采用方差分析或秩和检验进行统计学分析.结果 CHB或AsC组外周CD4~+T淋巴细胞中CD4~+CD25~+Foxp3~+T淋巴细胞频率以及CD4~+CD25~+T淋巴细胞中Foxp3 mRNA表达水平显著高于正常人对照组,差异有统计学意义(P<0.05).CHB患者和AsC血清中TGF β1水平显著高于正常人和乙型肝炎恢复者,并与CD4~+CD25~+Foxp3~+T淋巴细胞频率存在显著正相关(r=0.78,P<0.01).结论 CHB和AsC患者TGF β1与CD4~+CD25~+Foxp3~+调节性T淋巴细胞增高有密切关系.