The Distribution and the Fibrotic Role of Elevated Inflammatory Th17 Cells in Patients With Primary Biliary Cirrhosis

T helper (Th) 17 cells were reported to have the property of proinflammation and profibrosis. We first investigate the levels of Th17 cells in primary biliary cirrhosis (PBC) patients, and then explore their distribution and fibrotic role in the disease. We compared the circulating Th17 and hepatic interleukin (IL)-17-positive cells between patients and healthy controls (HCs) at different disease stages by flow cytometry and immunohistochemistry, respectively. The levels of chemokine (c-c motif) ligand (CCL) 20 were then measured. For exploration of the reason why Th17 cells increased, CD4(+)CD161(+) populations were sorted and cultured with IL-23 and IL-1β to analyze their proliferation and IL-17 secretions. The serum IL-23 and IL-1β were tested by enzyme-linked immunosorbent assay. The proliferation and expressions of α-smooth muscle actin and IL-8 of hepatic stellate cells (HSCs) were identified after stimulated by different concentrations of IL-17. Circulating and hepatic Th17 cells were elevated in PBC patients compared with HCs. Early PBC patients presented with more Th17 cells in periphery blood and less in the liver than advanced PBC patients. Accordingly, the levels of both serum and hepatic CCL20 for Th17 cells were higher, especially in those with advanced disease. The progenitor of Th17, CD4(+)CD161(+) cell was increased in PBC. Moreover, the percentage of Th17 cells was positively related with CD4(+)CD161(+) cell. After stimulation with IL-23 and IL-1β which were improved in PBC patients, CD4(+)CD161(+) cells from PBC patients expressed more IL-17, although their proliferation were not different between 2 groups. IL-17 can promote the proliferation of HSCs at a dose-dependent method, and also increase the IL-8 expression in a dose/time-dependent way. Anti-IL-17 can neutralize the above reactions. CD4(+)CD161(+) cells are a source of increased Th17 in PBC patients. With disease progression, Th17 population decreased in the circulation, accompanied by greater accumulation in the liver, which is regulated by CCL20 in advanced patients. IL-17 may be involved in the process of PBC fibrosis.