title: MAIT be different-persisting dysfunction after DAA-mediated clearance of chronic hepatitis C virus infection.
abstract: MAIT cells are an abundant innate-like T-cell subset that is defined by the invariant T-cell receptor (iTCR) V-alpha chain Vα7.2-Jα33. Little is currently known about their frequency and function in chronic hepatitis C virus (HCV) infection and their fate after therapy-mediated HCV elimination by direct acting antivirals (DAA). In this issue of the European Journal of Immunology, Hengst et al. [Eur. J. Immunol. 2016. 46: 2204-2210] give important novel insights into the biological role of MAIT cells in a relevant human chronic viral infection by showing that first, MAIT cells are only present at low frequencies in chronic HCV infection; second, circulating MAIT cells in HCV patients also display an altered phenotype; third, they are impaired in their MR-1-dependent effector functions and finally, and maybe most importantly, MAIT-cell frequency and function was not restored after HCV elimination by DAA therapy. These results suggest that MAIT cells are severely affected by a chronic human viral infection in their frequency and function and that this impairment is not reversed after HCV elimination. This is in contrast to rapid DAA-mediated restorations of NK-cell and CD8(+) T-cell functions, and indicates a differential impact of chronic infection and clearance on different immune cell subsets.
authors.affiliation: Clinic for Internal Medicine, Gastroenterology, Hepatology, Endocrinology and Infectious Diseases, Department of Internal Medicine, University Hospital Freiburg, Freiburg im Breisgau, Germany.
authors.forename: Maike
authors.initials: M
authors.lastname: Hofmann
authors.affiliation: Clinic for Internal Medicine, Gastroenterology, Hepatology, Endocrinology and Infectious Diseases, Department of Internal Medicine, University Hospital Freiburg, Freiburg im Breisgau, Germany. robert.thimme@uniklinik-freiburg.de.
authors.forename: Robert
authors.initials: R
authors.lastname: Thimme
mesh_terms: D019698:Hepatitis C, Chronic / Q000276:immunology*; D006801:Humans; D007694:Killer Cells, Natural; D000072336:Mucosal-Associated Invariant T Cells; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016176:T-Lymphocyte Subsets
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta
keywords: HCV; Immune responses; Inflammation; MAIT cells; T cells