The function of ENSG00000120337 (TNFSF18, TNF superfamily member 18) is as follows. Cytokine that binds to TNFRSF18/AITR/GITR. Regulates T-cell responses. Can function as costimulator and lower the threshold for T- cell activation and T-cell proliferation. Important for interactions between activated T-lymphocytes and endothelial cells. Mediates activation of NF-kappa-B. Triggers increased phosphorylation of STAT1 and up-regulates expression of VCAM1 and ICAM1 (PubMed:23892569). Promotes leukocyte adhesion to endothelial cells (PubMed:23892569). Regulates migration of monocytes from the splenic reservoir to sites of inflammation (By similarity). {ECO:0000250|UniProtKB:Q7TS55, ECO:0000269|PubMed:17449724, ECO:0000269|PubMed:18040044, ECO:0000269|PubMed:23892569}.