De novo membranous glomerulonephritis in renal allografts in children.

The incidence of de novo membranous glomerulonephritis (MGN) in transplanted kidneys is around 1 to 2%. In our series, of the 310 grafts that were examined by immunofluorescence microscopy (IF), 29 (9.3%) showed subepithelial IgG deposits, a pattern consistent with the diagnosis of MGN. Transplant biopsy had been performed because of the occurrence of proteinuria in 8 patients (pts), for suspected rejection in 16 and systematically in the remaining 9 who had no proteinuria and a normal renal function. In all cases the lesions were identified by IF and were confirmed by electron microscopy (EM) in 14 pts. Granular deposits of IgG were diffuse in 22 cases and segmental in 7. Sequential specimens were available in 17 pts and showed the persistence or the increase of the IgG deposits in all patients but one in whom they had disappeared. Age at transplantation (Tx) ranged from 2 years 3 months to 16 years. Grafts were from cadaveric donors in 27 pts and from living related donors in 2 pts. In none of the recipients was MGN the nephropathy of the native kidneys. With a follow-up of 18 to 74 months, 6 pts never developed a proteinuria. In the remaining 23, proteinuria developed 1 to 70 months after Tx, associated with a nephrotic syndrome (NS) in 6 pts.(ABSTRACT TRUNCATED AT 250 WORDS)