CTLA4 and autoimmune disease: In a recent study, GITR single-positive cells (GITRsp, CD4+CD25low/−Foxp3low/−GITR+) have been found that can express high levels of CTLA4, produce much more IL-10, and have regulatory activity, meaning that GITRsp cells might play a role in decreasing T cell activation/proliferation and controlling autoimmune disease [24].