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| IMAGE OF THE MONTH |
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| Year : 2021 | Volume
: 15
| Issue : 3 | Page : 284-285 |
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De novo membranous nephropathy in an allograft
Swarnalata Gowrishankar
Department of Histopathology, Apollo Hospitals, Hyderabad, Telangana, India
| Date of Submission | 07-Sep-2021 |
| Date of Decision | 10-Sep-2021 |
| Date of Acceptance | 14-Sep-2021 |
| Date of Web Publication | 30-Sep-2021 |
Correspondence Address:
Dr. Swarnalata Gowrishankar
Department of Histopathology, Apollo Hospitals, Jubilee Hills, Hyderabad - 500 096, Telangana
India
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/ijot.ijot_83_21
How to cite this article:
Gowrishankar S. De novo membranous nephropathy in an allograft. Indian J Transplant 2021;15:284-5 |
A 27-year-old male post-live-related-transplant with a native kidney biopsy-proven focal segmental glomeruosclerosis, on triple-drug immunosuppression, presented at 5-year posttransplant with 2 g proteinuria and a serum creatinine of 2.8 mg/dl. The biopsy showed 5 glomeruli with a diffuse basement membrane thickening with subepithelial spikes on the silver stain [Figure 1]. The glomeruli showed no increase in cellularity. Basement membrane duplication typical of transplant glomerulopathy was not seen. There was mild tubular atrophy, seen in the periodic acid–Schiff stain [Figure 1]. There is no significant interstitial inflammation or tubulitis. The C4d immune stain shows strong peripheral fine granular positivity in the glomeruli and strong linear circumferential positivity along the peritubular capillary walls [Figure 2]. | Figure 1: Glomeruli with basement membrane thickening (PAS stain). inset- spikes on silver stain
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The diagnosis was a chronic antibody-mediated rejection with a membranous pattern of injury or a de novo membranous nephropathy (MGN) which reflects alloimmune injury.
MGN in an allograft renal biopsy can be recurrent or de novo. Recurrent MGN occurs early, usually <3 months, is immunoglobulin G4 (IgG4) predominant, and has a native kidney diagnosis of MGN with elevated anti-PLA2R antibodies, if PLA2R mediated. De novo MGN, as in this case, is often an unusual manifestation of an antibody-mediated reaction, with anti-HLA-DQ antibodies demonstrable often. It occurs late posttransplant, >3 years and is IgG4 dominant. Circulating immune complexes are described with dnMN, IgG is targeted against brush border or tubular epithelial or interstitial antigens instead of podocyte antigens as seen in pMN. dnMN is less often associated with antiPLA2R. In dnMN an initial trigger such as viral infection, urinary obstruction, ischemia, or an immunological process may lead to podocyte damage. If that trigger is severe, cryptic podocyte protein antigens (different from those involved in primary MN, eg, PLA2R) may be exposed and drive an immune response with formation of in situ antigen–antibody immune complexes and the typical subepithelial deposits of MN. C4d stain in both recurrent and de novo MGN has a peripheral fine granular pattern but as in this case, peripheral linear deposits along the peritubular capillaries occur only in de novo MGN.
Transplant glomerulopathy is the other differential diagnosis to be considered. Here, there is a duplication of the basement membrane with C4d positivity and this pattern can coexist with a membranous pattern.
De novo MGN has a poor prognosis with a 5-year graft loss of >50% and 67% of the cases progressing to end-stage renal disease.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for images and other clinical information to be reported in the journal. The patient understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2]
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