Integrative molecular profiling of autoreactive CD4 T cells in autoimmune hepatitis

[摘要] Background & Aims: In most autoimmune disorders, crosstalk of B cells and CD4 T cells results in the accumulation of autoantibodies. In autoimmune hepatitis (AIH), the presence of antisoluble liver antigen (SLA) autoantibodies is associated with reduced overall survival, but the associated autoreactive CD4 T cells have not yet been characterised. Herein, we isolated and deeply characterised SLA-specific CD4 T cells in patients with AIH. Methods: We used brief ex vivo restimulation with overlapping SLA peptides to isolate and phenotype circulating SLA-specific CD4 T cells, and integrative single-cell RNA-seq (scRNA-seq) to characterise their transcriptome and T-cell receptor (TCR) repertoire. Autoreactive TCRs were cloned and used to identifydominant SLA-derived epitopes. SLA-specific CD4 T cells were tracked in peripheral blood through TCR sequencing to identify their phenotypic niche. We further characterised disease-associated peripheral blood T cells by high-content flow cytometry in 42 patients with AIH and 17 controls with non-alcoholic steatohepatitis. Results: Autoreactive SLA-specific CD4 T cells were only detected in patients with anti-SLA autoantibodies and had a memory PD-1(+)CXCR5(-)CCR6(-)CD27(+) phenotype. ScRNA-seq revealed their proinflammatory/B-helper profile. SLA(81-100) and SLA(177-204) contain dominant T-cell epitopes. Autoreactive TCR clonotypes were predominantly found in the memory PD-1(+)CXCR5(-)CD4 T cells, which were significantly increased in the blood of patients with AIH and supported B-cell differentiation through IL-21. Finally, we identified specific T-cell phenotypes linked to disease activity and IgG level during AIH. Conclusions: We provide a deep characterisation of rare circulating autoreactive CD4 T cells and identify their peripheral reservoir in AIH. We also propose a specific phenotype of autoreactive T cells related to AIH disease activity, which will be essential to track, delineate, and potentially target these pathogenic cells. Lay summary: One principal characteristic of autoimmune hepatitis (AIH), like for many other autoimmune diseases, is the accumulation of autoantibodies produced by B lymphocytes following their interaction with autoreactive CD4 T lymphocytes. In this study, we identified and characterised with high resolution these CD4 T cells. This will be essential to track, delineate, and potentially target them during AIH. (C) 2020 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

[发布日期] 2020-12-01

[关键词] Autoimmune hepatitis;Autoreactive CD4 T cells;Single-cell RNA-seq;Soluble liver antigen;Autoreactive TCR clonotypes