AUTHOR=Phillips Sandra , Mistry Sameer , Riva Antonio , Cooksley Helen , Hadzhiolova-Lebeau Tanya , Plavova Slava , Katzarov Krum , Simonova Marieta , Zeuzem Stephan , Woffendin Clive , Chen Pei-Jer , Peng Cheng-Yuan , Chang Ting-Tsung , Lueth Stefan , De Knegt Robert , Choi Moon-Seok , Wedemeyer Heiner , Dao Michael , Kim Chang-Wook , Chu Heng-Chen , Wind-Rotolo Megan , Williams Roger , Cooney Elizabeth , Chokshi Shilpa TITLE=Peg-Interferon Lambda Treatment Induces Robust Innate and Adaptive Immunity in Chronic Hepatitis B Patients JOURNAL=Frontiers in Immunology VOLUME=Volume 8 - 2017 YEAR=2017 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2017.00621 DOI=10.3389/fimmu.2017.00621 ISSN=1664-3224 ABSTRACT=IFN-Lambda (IFNλ) is a member of the type III IFN family and is reported to possess anti-pathogen, anti-cancer and immuno-modulatory properties; however there are limited data regarding its impact on host immune responses in vivo. We performed longitudinal and comprehensive immuno-surveillance to assess the ability of pegylated (peg)-IFNλ to augment antiviral host immunity as part of a clinical trial assessing the efficacy of peg-IFNλ in Chronic Hepatitis B (CHB) patients. These patients were pre-treated with directly-acting antiviral therapy (Entecavir) for 12 weeks with subsequent addition of peg-IFNλ for up to 32 weeks. In a sub-group of patients, the addition of peg-IFNλ provoked high serum levels of anti-viral cytokine IL-18. We also observed the enhancement of NK cell poly-functionality and the recovery of a pan-genotypic HBV-specific CD4+ T cells producing IFN-γ with maintenance of HBV-specific CD8+ T cell antiviral and cytotoxic activities. It was only in these patients that we observed strong virological control with reductions in both viral replication and HBV antigen levels. Here we show for the first time that in vivo peg-IFNλ displays significant immuno-stimulatory properties with improvements in the main effectors mediating anti-HBV immunity. Interestingly, the maintenance in HBV-specific CD8+ T cells in the presence of peg-IFNλ is in contrasts with previous studies showing that peg-IFNα treatment for CHB results in a detrimental effect on the functionality of this important antiviral T cell compartment.