Proteinuria in the dog: a pathomorphological study of 51 proteinuric dogs.

Renal cortical biopsies of 51 dogs with spontaneous proteinuria were examined by histology, electron microscopy and immunofluorescence. Glomerular lesions were classified in four groups: mesangioproliferative, membranoproliferative and membranous glomerulonephritis and amyloidosis. The glomerular and the tubulointerstitial lesions were graded, using a semiquantitative system. The results were used for the calculation of correlation coefficients between several parameters. A positive correlation was found between the severity of glomerular and tubulointerstitial lesions. Fibrin detection by immunofluorescence and histochemical methods appeared not to be correlated. The presence of electron dense deposits correlated only with the fluorescence for IgG and C3. Fluorescence for IgA and IgM was frequently observed in cases with or without dense deposits.