An immunohistochemical study of extracellular matrix components and integrins in human glomerular diseases.

The localization of extracellular matrix components and their cell surface receptors (integrins) was studied in 130 subjects in order to clarify their participation in the progression and aggravation of various types of nephritis. Included in the study were 2 normal subjects, 14 patients with minimal change disease, 2 patients with minimal change nephrotic syndrome, 65 patients with IgA nephropathy, 18 patients with mesangial proliferative glomerulonephritis, 15 patients with membranous glomerulonephritis, 5 patients with membranoproliferative glomerulonephritis and 9 patients with systemic lupus erythematosus (SLE). The distribution of fibronectin (FN), vitronectin (VN), laminin (LN), heparan sulfate proteoglycan (HSPG), type III, IV, V, VI collagen, fibronectin receptor (FNR) and vitronectin receptor (VNR) in the glomerulus was studied employing the indirect immunoperoxidase method. FN, LN, type IV, V and VI collagen, FNR and VNR were found to be distributed in the expanded mesangial region in IgA nephropathy, mesangial proliferative glomerulonephritis and membranoproliferative glomerulonephritis. Deposition of VN was observed in some of the patients. In membranous glomerulonephritis and membranoproliferative glomerulonephritis, the distribution of FN, LN, type IV collagen, FNR and VNR was increased in the thickened loop wall and VN deposition was also observed. Quantitative and functional changes in the extracellular matrix and integrins, therefore, appear to participate in the progression and aggravation of glomerulonephritis.