TGFB1 and familial dilated cardiomyopathy: Leukocytes are known to modulate cardiac fibroblasts by virtue of secreted mediators of fibrosis, including transforming growth factor-β (TGF-β) (Bugger and Abel, 2014; Russo and Frangogiannis, 2016), however, whether DCM-induced fibrosis is preceded by leukocyte infiltration and activation has not been reported.