Urinary protein analysis of various renal diseases in childhood

-Significance of urinary protein analysis-

Abstract

β₂-microglobulin, lysozyme, transferrin and IgG were measured in unconcentrated 24-hr urine and serum from 12 healthy subjects and 134 patients with various renal diseases of glomerular or tubular type. The selectivity of proteinuria (glomerular and/or tubular) was defined as the slope of regression line relating the log of renal clearance of proteins relative to that of transferrin to the log of their molecular weight. The range of 24-hr urinary excretion in healthy subjects were 11-98μg/m²/day (Md. 40μg/m²/day) for β₂-microglobulin, 880-5, 000 ng/m²/day (Md. 2, 400 ng/m²/day) for lysozyme, 73-630 μg/m²/ day (Md. 240 pg/m²/day) for transferrin and 130-700 pg/m²/day (Md. 310 μg/m2/day) for IgG. The presence of glomerular damages were suggested in patients with heavy proteinuria (Ig/m²/day or over). The selectivity patterns were revealed a persistent presence of glomerular damages in patients of membrano-prolif erative glomerulonephritis, crescentic glomerulonephritis and Henoch-Schönlein purpura nephritis in spite of the decrease of urinary excretion of protein. The selectivity pattern (glomerular or tubular) was correlated with morphological findings and useful to diagnose the location of renal damage.