Histopathological studies on glomerular basement membrane and mesangium: Problem of peroxidase-antiperoxidase method

To classify the histopathological findings on the glomerular basement membrane (GBM) and mesangium, we carried out peroxidase-antiperoxidase (PAP) method using formalin-fixed and paraffin-embedded tissue on renal biopsy in the patients with IgA nephropathy and with membranous nephropathy. The PAP method was compared with direct and indirect immunofluorescence procedure. The cases in this series, consists of primary glomerular disease, such as 3 cases of minor glomerular abnormalities, 44 cases of IgA nephropathy and 35 cases of membranous nephropathy. The rabbit antisera to human IgG, IgA, IgM, Fibrinogen and C3 were examined in thease cases. As a result, the sensitivity of PAP method fairly correlated with direct immunofluorescence technique. Namely the correspondency of thease two methods were 80.0-96.4% in the GBM and 73.3-90.3% in the mesangial area respectively. Counterstain of PAP and Periodic acid-Schiff-hematoxylin (PAP-PAS) gave a definitely basical structure of the glomeruli and immunological deposition in the GBM or mesangium. This staining is very useful for the examination of pathogenesis of glomerular lesion. Counterstain of PAP and Colloidal iron is also useful for demonstration of detail localization of immune deposits and a situation of polyanion in GBM.