Hyperactivated peripheral invariant natural killer T cells correlate with the progression of HBV-relative liver cirrhosis.

Invariant NKT (iNKT) cells express markers of both T and NK cells and may produce various cytokines to regulate liver immunity. However, the role of iNKT cells in the progression of HBV-relative liver cirrhosis (HBV-LC) is incompletely understood. Here, we investigated the impact of peripheral iNKT cells on a cohort of patients with HBV-LC. The frequency, number, activation status, apoptosis and proliferation ability of peripheral iNKT cells were detected with flow cytometry. The impact of peripheral iNKT cells on the proliferation of hepatocyte cell line (MIHA) and activation of hepatic stellate cell line (LX-2) was detected with flow cytometry and PCR. In HBV-LC patients, the frequency and absolute number of peripheral iNKT cells significantly reduced, but the expression levels of CD25, interleukin (IL)-4, IL-13 and interferon (IFN)-γ increased. No difference was observed in the proliferation and apoptosis of circulating iNKT cells between patients and healthy controls (HCs). CXCR6 (CD186), known to be closely associated with iNKT cells migration from the periphery to the liver, was highly expressed on peripheral iNKT cells in HBV-LC patients. Furthermore, peripheral iNKT cells had a profound impact on MIHA cell proliferation and LX-2 cell activation through IL-4 or IL-13. Our data suggest that in HBV-LC patients, highly activated peripheral iNKT cells may migrate to the liver and affect hepatocyte cell line (MIHA) proliferation and hepatic stellate cell line (LX-2) activation through the expression of type 2 cytokines, which may result in excessive healing and contributing to the progression of fibrosis toward cirrhosis in liver.