IL-15-induced CD38+HLA-DR+CD8+ T cells correlate with liver injury via NKG2D in chronic hepatitis B cirrhosis.

OBJECTIVES

CD8+ T cells play a critical role in the immune dysfunction associated with liver cirrhosis. CD38+HLA-DR+CD8+ T cells, or bystander-activated CD8+ T cells, are involved in tissue injury but their specific contribution to liver cirrhosis remains unclear. This study sought to identify the mechanism for CD38+HLA-DR+CD8+ T cell-mediated pathogenesis during liver cirrhosis.

METHODS

The immunophenotype, antigen specificity, cytokine secretion and cytotoxicity-related indicators of CD38+HLA-DR+CD8+ T cells were determined using flow cytometry. The functional properties of these cells were assessed using transcriptome analysis. CD38+HLA-DR+CD8+ T-cell killing was detected using cytotoxicity and antibody-blocking assays.

RESULTS

The proportion of CD38+HLA-DR+CD8+ T cells was significantly elevated in liver cirrhosis patients and correlated with tissue damage. Transcriptome analysis revealed that these cells had innate-like functional characteristics. This CD8+ T-cell population primarily consisted of effector memory T cells and produced a high level of cytotoxicity-related cytokines, granzyme B and perforin. IL-15 promoted CD38+HLA-DR+CD8+ T-cell activation and proliferation, inducing significant TCR-independent cytotoxicity mediated through NKG2D.

CONCLUSIONS

CD38+HLA-DR+CD8+ T cells correlated with cirrhosis-related liver injury and contributed to liver damage by signalling through NKG2D in a TCR-independent manner.