Hypocomplementemic and normocomplementemic acute nephritis in children: a comparison with respect to etiology, clinical manifestations, and glomerular morphology.

Of 182 patients with acute glomerulonephritis, 20 had normal C3 levels at onset. Normocomplementemic and hypocomplementemic patients were similar with respect to incidence and site of preceding streptococcal infection, elevation of ASO titer, distribution by age, sex, race, season, and year,\and glomerular morphology by light and electron microscopy. They differed in that the normocomplementemic patients tended to have normal serum C5 levels and, for reasons not clear, reduced serum albumin and elevated cholesterol levels. The consistent absence by immunofluorescence of IgG in the glomeruli of five hypocomplementemic patients and its presence in five normocomplementemic patients was considered a chance observation. The data suggest that in each group the nephritis was poststreptococcal and that the mechanism producing poststreptococcal glomerulonephritis is capable of acting independently of that activating circulating C3.