Introduction Acute liver failure (ALF) is a sterile inflammation with a high mortality. The immunological response to acute liver injury is initiated by the infiltration of innate neutrophils and is followed by an adaptive T cells response. T cells in drug induced skin lesions have been shown to express neutrophil chemoattractant and there is also evidence that regulatory T cells (Tregs) in peripheral blood secrete IL-8. However, little is known on the ability of liver infiltrating T cell subsets to retain neutrophils in ALF or the function of Tregs. Our aim is to investigate the phenotypic features and cytokine profiles of circulating and liver infiltrating T cell subsets from ALF patients with a view of assessing their functional ability to retain neutrophils.
Methods Distribution and localisation of Liver infiltrating lymphocytes and neutrophils were assessed by immunohistochemistry. Peripheral blood and liver infiltrating lymphocytes were isolated from ALF patients. Intracellular-cytokines expression profiles of the lymphocytes subsets were assessed by flow cytometry. Functional status of T cells including Tregs was assessed by pSTAT5 signalling.
Results Immunohistochemistry revealed high numbers of neutrophils in ALF compared to chronic diseased livers (109 ± 12.2 vs. 7.1 ± 2.67; p = 0.01) and normal liver (109 ± 12.2 vs. 0.8 ± 0.33; p = 0.0002). Dual immunohistochemistry showed co-localisation of lymphocytes and neutrophils in areas of hepatic necrosis. Neutrophil chemoattractant IL-8 expression in peripheral blood was higher in lymphocyte subsets of ALF patients compared to normal donor, CD3 (2.3 ± 0.54% vs. 0.93 ± 0.4%; p = 0.23), CD4 (2.8 ± 2.2% vs. 1.1 ± 0.7%; p = 0.41), CD8 (2.2 ± 1% vs. 0.61 ± 0.09%; p = 0.43) and Treg (0.8 ± 0.4% vs. 0.2 ± 0.02%; p = 0.48). There was an up-regulation of IL-8 production in Tregs after 7 days of ex vivo expansion compared to day zero (1.63 ± 1% vs. 0.77 ± 0.42%; p = 0.44). IFN-γ expression in ALF peripheral blood compared with normal blood was (23.1 ± 6.2% vs. 11.1 ± 8.4%; p = 0.38) for CD3 (11.72 ± 2.3% vs. 7.8 ± 6.26; p = 0.5) for CD4 and (14.21 ± 3.04 vs. 9.95 ± 8.44; p = 0.58) for CD8 after day seven of ex vivo expression. Importantly, Tregs from both blood and explanted liver of ALF were functional indicated by STAT5 phosphorylation in response to IL-2.
Conclusion We demonstrated for the first time that lymphocyte subsets including Tregs in ALF produce IL-8, which may contribute to the retention of neutrophils in areas of hepatic necrosis in ALF. We also showed that Tregs and other T cells are functionally responsive to IL-2 in both blood and explanted liver tissue of ALF patients.
Disclosure of Interest None Declared.