Peripheral blood samples were obtained from HBV-ACLF patients, mild chronic hepatitis B (CHB) patients and healthy controls (HC). Circulating NK cells phenotype was determined using flow cytometry. Serum cytokine concentrations were ascertained using the CBA Inflammation kit. Cell apoptosis was analyzed using the FITC-annexin V Apoptosis Detection Kit.
Peripheral NK cells from HBV-ACLF expressed higher levels of TRAIL than those from CHB and HC. Expression of TRAIL on NK cells was correlated positively with serum IL-6 and IL-8 concentrations in HBV-ACLF patients, which is further confirmed by cytokines stimulation in vitro. NK cells caused a significant increase of apoptotic hepatocytes, and further increased the frequency of apoptosis in IL-6 and IL8-stimulated hepatocytes; the apoptosis was then inhibited partially by an anti-TRAIL monoclonal antibody.
These results suggested that inflammation cytokines elevated in patients with HBV-ACLF may promote NK cell mediated cytotoxicity through TRAIL pathway.