Mesangial cell activation in the collagenofibrotic glomerulonephropathy

Collagenofibrotic glomerulonephropathy is a new disease entity of unknown pathogenesis, which is characterized by the deposition of type III collagen within the mesangial matrix. We have investigated a case in which many mesangial cells in the type III collagen-deposited glomeruli were α-smooth muscle actin (ASMA) positive and showed an increase of subplasmalemmal filaments, indicating the activation and myofibroblastic transformation. It is suggested that the activated mesangial cells may synthesize the type III collagen deposited in the subendothelial space and mesangial matrix.