Involvement of natural killer T cells and granulocytes in the inflammation induced by partial hepatectomy

Background/Aims Natural killer T (NKT) cells are present in the liver of mice. We examined whether NKT cells and other leukocytes were associated with hepatic inflammation after partial hepatectomy. Methods Approximately 70% of the liver was removed from mice using the method described by Higgins and Anderson. Results Partial hepatectomy induced the expansion of NKT cells in the liver and the elevation of transaminase. These responses were completely suppressed by the administration of tacrolimus. NKT cell-deficient mice showed a decreased level of transaminase after partial hepatectomy. Perforin (−/−) mice showed an elevation of transaminase while B6-gld/gld mice (Fas ligand−) showed a decreased elevation of transaminase. In TAP-1(−/−) mice which lacked CD8+ cytotoxic T cells, inflammation remained at a normal level after partial hepatectomy. Since NKT cell-deficient mice showed up to 50% decrease in the level of inflammation, we examined the association of other leukocytes with the remaining inflammation. The number and proportion of granulocytes were increased by partial hepatectomy. Conclusions Both NKT cells and granulocytes participated in the hepatic inflammation after partial hepatectomy. The function of NKT cells, but not of granulocytes, was found to be sensitive to the immunosuppressive effect of tacrolimus.