TGFB1 and IgA glomerulonephritis: For example, in IgA nephropathy, glomerular fibrosis results from IgA activation of mesangial cells to secrete TNF-α, IL-6 and TGF-β (Julian et al. 1999; Lai et al. 2003) and in patients with IgA nephropathy, significantly reduced levels of glomerular BMP-7 were demonstrated in renal biopsy samples.