Long-term follow-up of type III membranoproliferative glomerulonephritis in children.

Seven patients with type III membranoproliferative glomerulonephritis (MPGN) were followed for 9-17 years. Their mean age at presentation was 11.0 years. Their urinary abnormalities were detected by school urinary screening in five, and two patients presented with nephrotic syndrome. With time, urinalysis became normal in five, proteinuria persisted in one and nephrotic syndrome persisted in one. All had serum creatinine levels below 1 mg/dl at the last follow-up. All were initially hypocomplementemic. Serum C3 levels became normal in five patients but decreased again in three without clinical changes. Mesangial proliferation was initially slight or moderate in five but, except for one patient, histological changes persisted in follow-up biopsies even though in two the urinalysis became normal. Electron micrographic studies using silver-methenamine staining revealed subepithelial and subendothelial deposits associated with basement membrane disruption and layering of the lamina densa, an abnormality typical of MPGN type III. These observations suggest long-term outcome of type III MPGN is good despite persisting changes in type III lesions.