CD8+ T cells specific to apoptosis-associated epitopes are expanded in patients with chronic HBV infection and fibrosis.

Ilenia Pacella, Ilenia Cammarata, Carmela Martire, Giuseppina Brancaccio, Giovanni Battista Gaeta, Vincenzo Barnaba, Silvia Piconese

Liver international : official journal of the International Association for the Study of the Liver 2021 Mar

filter terms:

During chronic viral infections, the apoptosis of activated T cell elicits a CD8+ T cell response directed to those cryptic epitopes that emerge from caspase-cleaved structural proteins. Such response directed to apoptosis-associated epitopes (AEs) contributes to the amplification of immunopathology. Here, we have analysed through flow cytometry AE-specific CD8+ T cells in patients with chronic hepatitis B virus (HBV) infection, naïve-to-treatment or undergoing nucleos(t)ide-analogue (NUC) therapy. We found that AE-specific CD8+ T cell frequencies were significantly increased only in those NUC-treated patients who also presented advanced hepatic fibrosis. Regulatory T cells were also expanded in those patients, and AE-specific, but not HBV-specific, CD8+ T cell frequency positively correlated with Treg percentages. Through multiparameter flow cytometry, multidimensionality reduction and unsupervised clustering analysis, we could identify novel subpopulations among effector memory (em) and emCD45RA+ T cell (Tem and Temra) subsets. CD8+ T cells with distinct specificities differentially populated the subpopulation map: while HBV-specific were mostly contained in the Tem subset, AE-specific CD8+ T cells encompassed naïve, as well as T central memory, Tem and Temra cells. All together, these findings indicate a link between AE-specific CD8+ T cells and advanced liver fibrosis in patients with chronic HBV infection, and suggest that virus-specific and AE-specific CD8+ T cells exhibit distinct differentiation states and contribute in distinct ways to immunopathology. © 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Citation

Ilenia Pacella, Ilenia Cammarata, Carmela Martire, Giuseppina Brancaccio, Giovanni Battista Gaeta, Vincenzo Barnaba, Silvia Piconese. CD8+ T cells specific to apoptosis-associated epitopes are expanded in patients with chronic HBV infection and fibrosis. Liver international : official journal of the International Association for the Study of the Liver. 2021 Mar;41(3):470-481