De novo and recurrent post-transplant membranous nephropathy cases show similar rates of concurrent antibody-mediated rejection

TL;DR

This study compares de novo and recurrent kidney transplant-related membranous nephropathy and finds similar rates of antibody-mediated rejection between the two.

Contribution

The study provides new insights into the similarities between de novo and recurrent post-transplant membranous nephropathy in terms of antibody-mediated rejection rates.

Findings

De novo and recurrent MN cases showed similar rates of concurrent antibody-mediated rejection.

PLA2R immunofluorescence positivity was higher in recurrent MN cases compared to de novo MN.

No significant histologic differences were found between the two groups except for IgG intensity.

Abstract

Membranous nephropathy (MN) can develop post-kidney transplant and is classified as a recurrent disease in patients with a history of MN in the native kidneys or as de novo disease in patients without such history. The mechanism of recurrent MN is thought to be like that of primary MN, but the mechanism of de novo MN is not well delineated. An association between de novo MN and antibody-mediated rejection (AMR) has been suggested.

A search of the pathology database from our medical center identified 11 cases of recurrent and 15 cases of de novo MN, in which clinical and histologic findings were compared. No significant differences were identified in the demographic characteristics, serum creatinine and proteinuria trends, or rates of allograft failure between the recurrent and de novo MN groups.

Rates of concurrent AMR were high in both groups (36% and 40%, respectively) but not statistically different from each other. PLA2R immunofluorescence (IF) positivity was seen in 64% of recurrent MN cases compared to 33% of de novo MN cases, suggesting a higher incidence of PLA2R-positive de novo MN than previously reported. No significant histologic differences were identified in the initial biopsies from the two groups, except mean IgG intensity by IF was higher in the recurrent group, suggesting a higher load of immune complex deposits at diagnosis in this group.

The findings do not provide support for a specific association between AMR and de novo MN, but whether there is a possible link between both forms of post-transplant MN and AMR remains an unanswered question.

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