1University Grenoble Alpes, Grenoble, F-38041 France; INSERM, U1209, Immunobiology and Immunotherapy of Chronic Deseases, La Tronche, F-38706 France.
2CHU Grenoble, Michallon Hospital, Hepato-gastroenterology unit, Grenoble, F-38043 France.
3University Grenoble Alpes, Grenoble, F-38041 France; INSERM, U1209, Analytic Immunology of chronic pathologies, La Tronche, F-38706 France.
4ANRS (France REcherche Nord & sud Sida-hiv Hépatites: FRENSH), Paris, France.
5Department of Virology, Henri Mondor Hospital, University Paris-Est and Inserm U955, Creteil, France.
6Sorbonne Universités, UPMC Univ Paris 06, INSERM, Institut Pierre Louis d'épidémiologie et de Santé Publique (IPLESP UMRS 1136), 75012, Paris, France.
7Hepato-gastroenterology department Hospital Saint Joseph, Marseille, 13008 France.
8INSERM U1052-CNRS 5286, Cancer Research Center of Lyon (CRCL), Lyon, France.
9Hepatology Department, Hospices Civils de Lyon, Lyon, France.
10Université de Lyon, Lyon, France.
11EFS Rhone-Alpes, R&D Laboratory, La Tronche, F-38701 France.
AbstractPegylated interferon α-2a (Peg-IFN-α) represents a therapeutic alternative to the prolonged use of nucleos(t)ide analog (NA) in chronic hepatitis B (CHB) infection. The mechanisms leading to a positive clinical outcome remain unclear. As immune responses are critical for virus control, we investigated the effects of Peg-IFN-α on both innate and adaptive immunity, and related it to the clinical evolution. The phenotypic and functional features of the dendritic cells (DCs), natural killer (NK) cells and HBV-specific CD4/CD8 T cells were analyzed in HBeAg-negative CHB patients treated for 48-weeks with NA alone or together with Peg-IFN-α, before, during and up to 2-years after therapy. Peg-IFN-α induced an early activation of DCs, a potent expansion of the CD56bright NK subset, and enhanced the activation and functionality of the CD56dim NK subset. Peg-IFN-α triggered an increase in the frequencies of Th1- and Th17-oriented HBV-specific CD4/CD8 T cells. Peg-IFN-α reversed the unresponsiveness of patients to a specific stimulation. Most of the parameters returned to baseline after the stop of Peg-IFN-α therapy. Peg-IFN-α impacts both innate and adaptive immunity, overcoming dysfunctional immune responses in CHB patients. These modulations were not associated with seroconversion, which questioned the benefit of the add-on Peg-IFN-α treatment.
PMID:27348813 [PubMed - in process] 作者: StephenW 时间: 2016-6-29 12:51
We provide a dynamic description of the innate and adaptive immunological changes during and up to 2 years after the course of an additional Peg-IFN-α therapy in CHB patients compared to patients receiving NA alone, whose clinical outcomes are known to be different. The findings increase the understanding of Peg-IFN-α immunomodulatory effects, and reveal yet unexplored immune effects of the combination therapy. However, as no seroconversion occurred in our cohort of patients, this work questions which function, direct antiviral or indirect immunomodulation, is more relevant in the efficacy of Peg-IFN-α in the treatment of CHB patients in the add-on settings.
Our data bring a larger view of the immunologic changes triggered by Peg-IFN-α therapy, also with a better subsetting definition and the full kinetics of the immune modulations, reinforcing the results of recent clinical trials [17–20, 23]. Firstly, Peg-IFN-α triggered a marked expansion of the CD56bright NK-cell subset accompanied by an activation and an enhanced functionality of the CD56dim NK-cell subset. CD56bright NK cells represent an intermediate stage of NK-cell differentiation, as a precursor of the CD56dim subset. Their unique immunoregulatory role [25] is illustrated by their preferential interactions with DCs, and their important role in early immune responses and in the shaping of subsequent adaptive responses [26]. Expansion of CD56bright NK cells has been described in several diseases, especially in HCV infection [27], in patients with multiple sclerosis treated with IFN-β [28], and interestingly in patients with active systemic lupus erythematosus [29], a disease mediated by elevated type-I IFN levels. Of note, we observed an inverse correlation between the absolute numbers of CD56bright NK cells and the decline in HBsAg titer. The distinct conclusions on NK functionality compared to other studies [19, 20] may be due to the different ways of data analysis, either as absolute numbers of functional NK cells [19] or as percentages of functional cells within the NK population [20], the time point (point of kinetics or the end of treatment) and the groups that were compared (responders versus non-responders, pre- and on-treatment points).
Moreover, Peg-IFN-α triggered as soon as 4 weeks an activation of pDCs and mDCs, which are critical in antiviral responses [30]. Indeed, type-I IFN is essential for DC maturation and activation [31], and to favor the cross-presentation of antigens by DCs [32], which can help promote subsequent cross-priming of antiviral T cells and facilitate viral clearance. Since DCs are essential to activate NKs and antiviral responses [33], modulation of DCs by Peg-IFN-α may affect the subsequent DC-NK cross-talk and potentiate NK-cell and T-cell functions. This hypothesis is supported by the strong correlation observed between the percentages of activated CD69+CD56dim NK cells and CD86+ pDCs. Thus, Peg-IFN-α may restore the pDC/NK cross-talk [6], subsequently enhancing antiviral NK-cell responses that could optimize the elimination of infected hepatocytes.
We also revealed key effects of Peg-IFN-α on adaptive immunity. We observed the elicitation of HBc- and HBs-specific CD4 and CD8 immune responses during Peg-IFN-α therapy. This is in contrast with prior observations that Peg-IFN-α did not improve peripheral HBV-specific T-cell responses [17, 22]. The discrepancy may be due to the time of analysis (very early versus late), and/or the use of frozen cells stimulated once with the peptide pools, whereas we performed two rounds of stimulation on freshly isolated PBMCs. Our data are consistent with the previously described restoration of HBV-specific T-cell responses following Peg-IFN-α therapy [23, 34, 35]. In addition, we have shown for the first time the elicitation of Th17 cells upon Peg-IFN-α treatment, preceding the induction of Th1-oriented immunity. Although IL17-producing T cells are described as pro-inflammatory cells and have been associated with liver damage [36], plasma IL17A levels and Th17 cell frequency are negatively correlated with viral load in patients with CHB infection [37]. Such a Th17 profile is revealed only upon specific stimulation with HBV-derived peptide pools and only in the Peg-IFN-α group, suggesting that Th17 cells are either HBV-specific T cells or that HBV-specific T cells subsequently activate other T cells to produce IL17. Interestingly, Th17 cells have been involved in the establishment of long-term immune memory and for promoting B-cell class switch [38]. Thus, they may regulate cellular and humoral antiviral immune responses, therefore favoring the elicitation of HBV-specific immune responses crucial for the immune control of HBV infection.
By potently modulating both the virus fitness and immunity, Peg-IFN-α appears to trigger a systemic immune activation and overcome the functional impairments to subsequently drive antiviral immunity. Despite evident immunologic changes, patients did not achieve HBsAg seroconversion in this cohort. In the overall ANRS HB06 PEGAN trial, HBsAg clearance at W48 has been achieved in only 8% of the patients treated by Peg-IFN-α (7/90) (Bourliere et al. J Hepatol 62, S2, S249, 2015). HBsAg clearance was associated with a low baseline HBs Ag titers and a history of HBeAg seroconversion prior to the inclusion into the trial, which suggests a potential spontaneous anti-viral immune activation. Immune modulations triggered by the therapy might even though improve clinical parameters. The two patients who underwent the highest decline in HBsAg during Peg-IFN-α therapy had the highest level of activated pDCs and NK cells at the end of treatment. The inverse correlation between the absolute numbers of CD56bright NKs and the down-regulation of HBsAg suggested a relationship between the immunologic and virological changes. Strikingly, we identified immunologic changes that persisted for up to 2 years after the cessation of the treatment in the absence of HBsAg seroconversion, as illustrated by the reversion of the unresponsiveness to the peptide-loaded pDCs.
Peg-IFN-α therapy profoundly affects both innate and adaptive immunity, but only transiently and without leading to HBsAg seroconversion. By identifying yet unexplored immune effects of the combination therapy, our study illustrates the pleiotropic action of IFN-α. However, as shown by the other groups, most of the immune changes returned to baseline after the cessation of Peg-IFN-α treatment. The immune alterations induced by Peg-IFN-α treatment failing in the majority of cases to induce seroconversion, they are probably less determinant than the direct antiviral effect of this cytokine. Our work questioned the benefit of the add-on Peg-IFN-α treatment over the NA or Peg-IFN-α monotherapies.作者: StephenW 时间: 2016-6-29 13:00