Tubular lesions in the nephrotic syndrome

The problem of accompanying tubular lesions in nephrotic syndrome (NS) is not yet sufficiently clarified. The tubular changes were studied by the urine excretion of sensitive markers: beta 2-microglobulin (beta 2m), alaninaminopeptidase (AAP) and gammaglutamyltranspeptidase (gamma GTP). Beta 2m was determined by ELISA method and AAP and gamma GTP--electrophoretically. 75 patients were examined--37 patients with idiopathic nephrotic syndrome (INS), 27 patients with membranous glomerulonephritis (MGN), 11 patients with membranous-proliferative glomerulonephritis (MPGN). The most sensitive index AAP was elevated in the urine of 97,4% of the patients with nephrotic syndrome, beta 2m was elevated in 64,3% and gamma GTP--in 46,2% of the patients. There is a positive correlation between the excretion of APP and the quantity of proteinuria (r = 0,73, p less than 0,001). The comparison of the results of the patients with and without nephrotic syndrome established that in the patients with idiopathic nephrotic syndrome as well as in the patients with membranous glomerulonephritis the presence of nephrotic syndrome determines the higher excretion of AAP (p less than 0,02). The presence of nephrotic syndrome increases the frequency and the severity of the tubular impairment in glomerulonephritis. The tubular impairment is independent of the histologic type but is in positive correlation with the proteinuria.