TNFRSF18 and Hepatic fibrosis: LX-II cells did not express GITR based on flow cytometry results (Fig. S3A), and recombinant GITRL did not significantly upregulate their expression of collagen-I and collagen-III over 1.2-fold (Fig. S3B), suggesting that knocking out GITRL does not attenuate liver fibrosis by directly acting on hepatic stellate cells.