Quantitative comparison of glomerular basement membrane thickness and density of the deposits in nonlupus and lupus mesangiocapillary glomerulonephritis type I. A ultrastuctural study.Fifteen renal biopsy specimens from patients with idiopathic (nonlupus) mesangiocapillary glomerulonephritis type I (MCGN-I) and eleven with lupus MCGN-I (selected from cases comprising class IV according to WHO classification) for whom both light and electron microscopy as well as immunofluorescence microscopy and full clinical data were available were examined quantitatively and compared with six cases of normal controls. Morphometric investigations of the electron micrographs were performed by means of a computer image analysis system to compare glomerular basement membrane (GBM) thickness and the electron - microscopic density of the deposits in nonlupus and lupus MCGN-I as well as to study whether these parameters could correlate with the clinical data. The study revealed that the mean values of the deposit area per GBM area and the GBM thickness in lupus MCGN-I patients were significantly increased in comparison with nonlupus group. There were significant positive correlations between deposit area per GBM area as well as the GBM thickness and proteinuria in both nonlupus and lupus patients. Similarly, we also observed significant positive correlations between these parameters and hematuria. In both nonlupus and lupus groups correlations between deposit area per GBM area and serum creatinine as well as between GBM thickness and serum creatinine were positive, but only in lupus MCGN-I patients, the relationship between deposit area per GBM area and serum creatinine, reached statistical significance.

Keywords: mesangiocapillary glomerulonephritis type I, lupus nephritis, density of the deposits, basement membrane thickness, glomerular