Although the source of the levels of serotype GITRL is currently unclear in this work, we speculate that activated dendritic cells could be one of the major cell types for GITRL overproduction in SLE patients, as indicated by recent findings that significantly increased expression of GITRL was detected in CD11c+ DCs during the development of experimental arthritis in mice [21]. Here, TNFSF18 is linked to systemic lupus erythematosus.