Because we recently demonstrated that CD4+CD25low/-GITR+ T cells circulating in healthy subjects possess regulatory activity and other features of Tregs, including anergy [36], we were interested in analyzing number and function of CD4+CD25low/-GITR+ T cells in SLE patients in comparison with those of CD4+CD25highGITR− cells. Here, TNFRSF18 is linked to systemic lupus erythematosus.