Imprint of unconventional T‐cell response in acute hepatitis C persists despite successful early antiviral treatment

• Published in: European journal of immunology 2022-03, Vol.52 (3), p.472-483
• Main Authors: Du, Yanqin, Khera, Tanvi, Strunz, Benedikt, Deterding, Katja, Todt, Daniel, Woller, Norman, Engelskircher, Sophie Anna, Hardtke, Svenja, Port, Kerstin, Ponzetta, Andrea, Steinmann, Eike, Cornberg, Markus, Hengst, Julia, Björkström, Niklas K., Wedemeyer, Heiner
• Format: Article
• Language: English
• Subjects: acute hepatitis C; Antigens; Antiviral Agents - therapeutic use; CD4 and CD8 double‐negative αβ T cells (DNT cells); CD4 antigen; CD8 antigen; CD8-Positive T-Lymphocytes; Cell activation; Chronic infection; Cytokines; direct‐acting antivirals (DAA); gamma delta T cells (γδ T cells); Genotype & phenotype; Hepacivirus; Hepatitis C; Hepatitis C - drug therapy; Hepatitis C, Chronic; Humans; Infections; Inflammation; Lymphocytes; Lymphocytes T; Medicin och hälsovetenskap; Mucosa; Mucosal-Associated Invariant T Cells; mucosal‐associated invariant T (MAIT) cells; Phenotypes
• ISSN: 0014-2980; 1521-4141; 1521-4141
• DOI: 10.1002/eji.202149457

Unconventional T cells (UTCs) are a heterogeneous group of T cells that typically exhibit rapid responses toward specific antigens from pathogens. Chronic hepatitis C virus (HCV) infection causes dysfunction of several subsets of UTCs. This altered phenotype and function of UTCs can persist over time even after direct‐acting antiviral (DAA)‐mediated clearance of chronic HCV. However, it is less clear if and how UTCs respond in acute, symptomatic HCV infection, a rare clinical condition, and if rapid DAA treatment of such patients reverses the caused perturbations within UTCs. Here, we comprehensively analyzed the phenotype and reinvigoration capacity of three major UTC populations, mucosal‐associated invariant T (MAIT) cells, γδ T cells, and CD4 and CD8 double‐negative αβ T cells (DNT cells) before, during, and after DAA‐mediated clearance of acute symptomatic HCV infection. Furthermore, MAIT cell functionality was systematically studied. We observed a reduced frequency of MAIT cells. However, remaining cells presented with a near‐to‐normal phenotype in acute infection, which contrasted with a significant dysfunction upon stimulation that was not restored after viral clearance. Notably, DNT and γδ T cells displayed a strong activation ex‐vivo in acute HCV infection, which subsequently normalized during the treatment. In addition, DNT cell activation was specifically associated with liver inflammation and inflammatory cytokines. Altogether, these data provide evidence that UTCs respond in a cell type‐specific manner during symptomatic HCV infection. However, even if early treatment is initiated, long‐lasting imprints within UTCs remain over time. Double‐negative αβ T cells (DNT) and γδ T cells displayed activation in acute HCV infection, which subsequently normalized during the treatment. Mucosal‐associated invariant T (MAIT) cells presented with a near‐to‐normal phenotype in acute infection while they displayed significant dysfunction upon stimulation that was not restored after viral clearance.