Formation of basement membrane in extracapillary proliferates in rapidly progressive glomerulonephritis.

In the extracapillary proliferations (crescents) of the glomeruli in glomerulonephritis, basement membranes appear and in addition "secretory bodies" are formed in the cisternae of the rough endoplasmatic reticulum. The findings permit the conclusion that proliferated visceral epithelial cells are involved in the crescent formation to a greater extent than previously assumed.