Thus, conditional deletion of TGFβ1 expression in CD4+ and CD8+ T-cells (by crossing mice carrying a conditional floxed allele of TGFβ1 with mice expressing CD4-Cre) resulted in age-related autoimmune disease, characterised by T-cell activation and colitis (Li et al. 2007). Here, TGFB1 is linked to autoimmune disease.