[Membranoproliferative glomerulonephritis. Variability of a morphologically definable disease].

The term of membranoproliferative glomerulonephritis (MPGN) has emerged from the morphologic evaluation of renal biopsies. The clinical picture associated with this pattern varies between apparent acute glomerulonephritis (GN), the steroid-resistent nephrotic syndrome, a combination of both, or asymptomatic protein uria and microscopic hematuria--with or without persistent depression of serum complement (C3). The histological picture is subdivided into the classical, lobular, crescentic or focal pattern. According to fine structural differences in the basement membrane changes 3 types can be recognized. An attempt is made to summarize the present understanding of this MPGN complex in its clinical, serological and morphological variability. The condition is compared to the proliferative form of lupus nephritos. A case of focal type I MPGN is presented with documentation of three serial biopsies. The Arbeitsgemeinschaft für Pädiatrische Nephrologie is conducting a cooperative MPGN study so far including 54 children and adolescents.