De Novo Membranous Nephropathy Associated With Antibody-Mediated Rejection in Kidney Transplant Recipients

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

Background

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.

Methods

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.

Results

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.

Conclusion

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.

Post-Transplant Glomerulonephritis: Challenges and Solutions

Glomeruli can be damaged in several conditions after kidney transplantation, with a potential impact on the graft function and survival. Primary glomerulonephritis, a group of glomerular immunological damage that results in variable histological patterns and clinical phenotypes, can occur in kidney transplant recipients as a recurrent or de novo condition. Specific immunologic conditions associated with kidney transplantation, such as acute rejection episodes, can act as an additional trigger after transplantation, impacting the incidence of these glomerulopathies. The post-transplant GN recurrence ranges from 3% to 15%, varying according to the GN subtype and post-transplant time, mainly occurring after 3-5 years of kidney transplantation. Advances in the knowledge of glomerulonephritis pathophysiology have provided new approaches to pre-transplant risk evaluation and post-transplant monitoring. Glomeruli can be affected by several systemic viral infections, such as human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV), severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), cytomegalovirus (CMV), and BK virus. The diagnosis of these infections, as well as the identification of possible complications associated with them, are important to minimize the negative impacts of these conditions on kidney transplant recipients' outcomes.

A Case of De Novo Membranous Nephropathy Causing Renal Transplant Rejection

We present a novel case of de novo membranous nephropathy (DNMN) leading to transplant rejection in a 51-year-old female patient. The patient has a transplant history of two renal transplants for end-stage renal disease due to lupus nephritis. She had a prior unrelated, living donor kidney transplant that was subsequently replaced by a deceased donor kidney transplant due to graft failure. This patient’s case is intriguing because DNMN is a rare cause of transplant rejection, and the literature demonstrates a scarcity of clinical examples. Interestingly, post-transplant DNMN has been suggested to be a separate disease from recurrent post-transplant MN and is associated with separate risk factors and diagnostic findings. As DNMN is considered a manifestation of antibody-mediated rejection, it should be treated with immunosuppressive therapy. As such, the presented case has received immunosuppressive therapy. In addition, DNMN is associated with humoral alloimmunity. Potentially other inflammatory processes (such as infection/potential UTI in our patient’s case) could cause exposure to undetectable donor antigens on renal transplants leading to antibody-mediated rejection via DNMN.