CONGENITAL NEPHROSIS OF THE FINNISH TYPE (CNF) - MATRIX COMPONENTS OFTHE GLOMERULAR-BASEMENT-MEMBRANES AND OF CULTURED MESANGIAL CELLS

Congenital nephrosis of the Finnish type (CNF) is a hereditary renal d isease of unknown aetiology manifested by massive proteinuria of the n ewborn and unresponsive to any treatment. In this study kidney samples and cultured glomerular mesangial cells from five patients with CNF w ere studied by indirect immunofluorescence microscopy for the presence and location of major basement membrane matrix (GBM) components. Hist ological changes of glomeruli ranging from mild thickening of basement membranes to total obliteration and sclerosis were seen. Notably, thi ckening of the subepithelial layer of Bowman's capsules was regularly seen along with hypercellularity at the juxtaglomerular areas. The mat rix components studied (laminin, plasma- and cellular fibronectin, typ e IV collagen, including the NC-1, alpha-1 and alpha-3 chains, heparan sulphate proteoglycan (HSPG) core protein, thrombospondin) were chara cteristically seen within the glomeruli. Local thickenings alternating with total loss of epitopes along the GBM were seen, especially with anti-type IV collagen and anti-HSPG antibodies. Sera from CNF patients after transplantation failed to show antibodies against GBM structure s in immunofluorescence microscopy, suggesting that no missing epitope s of GBM are introduced with the transplant kidney. Cultured mesangial cells of CNF glomeruli also showed continued in vitro production of t he matrix components and their incorporation into the matrix underneat h the cell layer.