TGFB1 and Nephropathy: Furthermore, rhIL-15 treatment at 1 ng/mL efficiently counteracts rhTGF-β1-induced apoptosis, through the MAPK pathway depending on the IL-15Rβγ complex (supplementary Figure S5), demonstrating that the survival factor IL-15 can interfere directly with tubular TGF-β-induced apoptosis which correlates with tubulointerstitial fibrosis in experimental nephropathies [21].