IMMUNOHISTOLOGICAL AND ULTRASTRUCTURAL DIFFERENCES BETWEEN RECURRENT TYPE-I MEMBRANOPROLIFERATIVE GLOMERULONEPHRITIS AND CHRONIC TRANSPLANTGLOMERULOPATHY

In renal transplant recipients with type I membranoproliferative glome rulonephritis (MPGN), the posttransplantation course can be complicate d by a recurrence of the original disease. However, it is well known t hat a recurrence of type I MPGN and chronic transplant glomerulopathy (CTG) cannot easily be distinguished. It has been suggested that the t wo entities can be differentiated by using electron microscopy (EM) an d immunofluorescence (IF) techniques. However, studies are lacking tha t compare biopsy specimens from patients with either a recurrence of t ype I MPGN or CTG, We have studied renal biopsy specimens from 10 pati ents with CTG and compared the ultrastructural and IF findings with bi opsy specimens from 12 patients with a possible recurrence of type I M PGN. AII the patients with CTG showed an electron-lucent zone of finel y flocculent material in the subendothelial space, whereas all patient s with a recurrence of type I MPGN showed subendothelial electron-dens e deposits on EM, On IF, all patients with CTG showed immunoglobulin F n (IgM) with greater intensity than C3. For the patients with recurren t type I MPGN, the opposite was true. Eleven specimens showed C3 depos its with greater intensity than IgM, and in one patient, C3 and IgM we re found in equal intensity. In conclusion, when IF and EM studies are available, CTG and recurrence of type I MPGN can reliably be distingu ished. (C) 1998 by the National Kidney Foundation, Inc.