[Podocytopathie and transdifferentiation of the podocytes in human glomerulonephritis. An immunomorphological study].

Transdifferentiation is characterized by a loss of normal epitopes by differentiated cells, accompanied by the acquisition of new epitopes and new functions. Podocytes are differentiated epithelial cells that cover and adhere to the outer surface of the glomerular basement membrane (GBM). The podocyte/GBM complex contributes to the selective filter function of the glomerular tuft. We have shown that, in various human glomerulonephritides, "dysregulated" podocytes acquire the potential to proliferate and multiply, undergo profound morphologic changes, detach from the GBM, and show phenotypic changes indicative of transdifferentiation. In the course of these events they lose their original epitopes and acquire macrophagic markers.