CD8A and Alzheimer disease: Skin CD4+ and CD8+ T cells from Oxa-treated Gli2ΔC2 mice showed decreased pSmad2/3 expression compared with WT mice, whereas skin CD4+ and CD8+ T cells from Oxa-treated Gli2ΔN2 mice had increased pSmad2/3 expression compared with WT mice (Figure 8, D and E), indicating that TGF-β production requires Hh-dependent Treg function in chronic AD and TGF-β signals directly to skin Teffs.