Renal distribution of collagen types III, IV and V in various glomerular diseases

Abstract

The purpose of this study is to examine the immunochemical changes of the glomerular basement membrane (GBM) and the mesangium, in pretreated paraffin-embedded sections with trypsin by utilizing monoclonal antibodies to type III (anti-III), type IV (anti-IV) and type V (anti-V) collagens. We observed 6 normal kidneys and 44 kidneys with various renal diseases. In normal human kidney the staining with anti-IV demonstrated GBM, mesangium, Bowman's BM, tubular BM and capillary BM. Anti-V was also seen in the interstitium. On the other hand, anti-III stained only interstitium. Thickened GBM in membranoproliferative glomerulonephritis (MPGN) and diabetic nephropathy, and irregular GBM in Membranous Nephropathy and Alport's syndrome were also evident in anti-IV stain, while widened mesangial area was seen in anti-V rather than anti-IV stain. In severely proliferative GN, anti-III as well as anti-IV and anti-V was detected in the mesangium in spite of existence of neither adhesion nor Bowman's gap. In MPGN type II, anti-III was observed along the GBM. In obsolescent glomeruli, anti-IV was not always detected although anti-V was constantly seen. On the other hand, anti-III was markedly positive in the crescents and obsolescent glomeruli. These results suggest that it is possible for mesangial, endothelial and epithelial cell to produce several types of collagens and type III collagen is closely related to the process of the glomerular obsolescence.