Recurrent proliferative glomerulonephritis with monoclonal immunoglobulin G deposits leads to rapid graft loss after kidney transplantation: a case report

Kidney Transplantation in Patients With Monoclonal Gammopathy of Renal Significance

Monoclonal gammopathy of renal significance (MGRS) defines disorders characterized by direct or indirect kidney injury caused by a monoclonal immunoglobulin produced by a B-cell or plasma-cell clone that does not meet current hematologic criteria for therapy. MGRS-associated kidney diseases are diverse and can result in the development of end-stage kidney disease. The current paradigm states that the underlying hematologic condition should be treated and in deep remission before kidney transplantation can be performed because recurrence has been reported for all MGRS-associated kidney diseases. However, we suggest that decisions regarding kidney transplantation in MGRS patients should be individualized considering many factors such as the subtype of MGRS-associated kidney disease, patient age and comorbidity, presence and risk of extrarenal complications, estimated waiting time, the availability of a living kidney donor, and previous hematological treatment and response. Thus, kidney transplantation should be considered even in treatment-naive patients, with hematological treatment initiated after successful kidney transplantation.

Overexpression of Plasmalemmal Vesicle-Associated Protein-1 Reflects Glomerular Endothelial Injury in Cases of Proliferative Glomerulonephritis with Monoclonal IgG Deposits

Introduction

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) occasionally presents refractory nephrotic syndrome resulting in poor renal prognosis, but its etiology is not fully elucidated. Given that glomerular endothelial cell (GEC) stress or damage may lead to podocytopathy and subsequent proteinuria, as in thrombotic microangiopathy (TMA), diabetic kidney disease, and focal segmental glomerulosclerosis, we investigated the evidence of glomerular endothelial injury by evaluating the expression of plasmalemmal vesicle-associated protein-1 (PV-1), a component of caveolae in the cases of PGNMID.

Methods

We measured the immunofluorescent PV-1 intensities of 23 PGNMID cases and compared with those of primary membranoproliferative glomerulonephritis (MPGN) (n = 5) and IgA nephropathy (IgAN) (n = 54) cases. PV-1 localization was evaluated with Caveolin-1, and CD31 staining, and the ultrastructural analysis was performed using a low-vacuum scanning electron microscope (LVSEM). To check the association of podocyte injury, we also conducted 8-oxoguanine and Wilms tumor 1 (WT1) double stain. We then evaluated PV-1 expression in other glomerulitis and glomerulopathy such as lupus nephritis and minimal change disease.

Results

The intensity of glomerular PV-1 expression in PGNMID is significantly higher than that in the other glomerular diseases, although the intensity is not associated with clinical outcomes such as urinary protein levels or renal prognosis. Immunostaining and LVSEM analysis revealed that glomerular PV-1 expression is localized in GECs in PGNMID. 8-oxoguanine accumulation was detected in WT1-positive podocytes but not in PV-1-expressing GECs, suggesting GEC-derived podocyte injury in PGNMID.

Conclusion

PV-1 overexpression reflects glomerular endothelial injury, which could be associated with podocyte oxidative stress in PGNMID cases.

Recurrence of Proliferative Glomerulonephritis with Monoclonal Immunoglobulin G Deposits with a Striated Ultrastructure

A 64-year-old man with nephrotic syndrome was admitted to another hospital where his renal biopsy revealed membranoproliferative glomerulonephritis (MPGN) with monoclonal immunoglobulin (Ig) G, subclass 1, κ light chain (IgG1κ) deposition on immunofluorescence (IF). Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) was suspected due to monoclonal IgG1κ deposits and the absence of hematological abnormalities. However, the typical PGNMID phenotype was not observed by electron microscopy. Instead, an organized and striated muscle-like structure was observed in the subendothelial space. Since a 2-year treatment with immunosuppressants did not improve his proteinuria, a second biopsy was performed at our hospital. It showed an MPGN-like phenotype; however, monoclonal Ig deposits on IF were no longer observed. One year after the second biopsy, he developed ESRD. Thus, he underwent living kidney transplantation from his wife. Allograft biopsy was performed as proteinuria was observed 3 months after transplantation, which again showed an MPGN-like phenotype with monoclonal IgG1κ deposits. The observed electron-dense deposits were similar to those in the native biopsies. Accordingly, the patient was diagnosed with recurrent MPGN. Adding methylprednisolone pulse therapy to conventional immunosuppressants did not improve the patient's renal function or proteinuria. He died of Legionella pneumonia 8 months after transplantation. Considering the patient's histological findings of MPGN with monoclonal IgG1κ deposits and early recurrence of glomerulonephritis after transplantation, he was diagnosed with PGNMID with novel electron-dense deposits.

Monoclonal immunoglobulin G deposits on tubular basement membrane in renal allograft: is this significant for chronic allograft injury?

Background

Tubular basement membrane immune deposits (TBMID) has rarely been observed in renal allografts. It is usually found in BK virus nephropathy and immune complex glomerulonephritis; however, its significance is not well understood. We conducted a retrospective clinicopathological study on monoclonal immunoglobulin G (IgG) TBMID.

Methods

We studied 7177 renal allograft biopsy specimens obtained from Tokyo Women’s Medical University from 2007 to 2015 and performed light microscopic, electron microscopic and immunofluorescence studies.

Results

Tubular basement membrane (TBM) deposits of IgG were found in 73 biopsies from 61 patients and the IgG subclass was obtained in 31 biopsies. There were no cases of monoclonal IgA or IgM TBMID. In total, 13 biopsies from 10 patients showed monoclonal IgG TBMID. Of these, seven showed monoclonal IgG1κ TBMID and one each showed monoclonal IgG2κ, IgG2λ and IgG3κ TBMID. Conversely, eight patients showed polyclonal IgG TBMID. In electron microscopy, large granular electron-dense deposits (EDDs) in the TBM were detected in all patients with monoclonal IgG1κ TBMID. EDDs were absent in TBM in patients with monoclonal IgG2κ, IgG2λ or IgG3κ TBMID. Progression of interstitial fibrosis and tubular atrophy (IFTA) was significantly higher in patients with monoclonal IgG1κ TBMID than in those with polyclonal IgG TBMID (P < 0.05). There were no significant differences in the other clinical parameters between monoclonal IgG1κ and polyclonal IgG TBMID.

Conclusions

This is the first study of patients with monoclonal IgG TBMID in renal allografts. We found that monoclonal IgG1κ TBMID was associated with EDD formation in TBM and IFTA progression.

Clinical course and outcome after kidney transplantation in patients with C3 glomerulonephritis due to CFHR5 nephropathy

BACKGROUND

Complement factor H-related protein 5 (CFHR5) nephropathy is an inherited renal disease characterized by microscopic and synpharyngitic macroscopic haematuria, C3 glomerulonephritis and renal failure. It is caused by an internal duplication of exons 2-3 within the CFHR5 gene resulting in dysregulation of the alternative complement pathway. The clinical characteristics and outcomes of transplanted patients with this rare familial nephropathy remain unknown.

METHODS

This is a retrospective case series study of 17 kidney transplant patients with the established founder mutation, followed-up over a span of 30 years.

RESULTS

The mean (±SD) age of patients at the time of the study and at transplantation was 58.6 ± 9.9 and 46.7 ± 8.8 years, respectively. The 10- and 15-year patient survival rates were 100 and 77.8%, respectively. Proteinuria was present in 33.3% and microscopic haematuria in 58.3% of patients with a functional graft. Serum complement levels were normal in all. 'Confirmed' and 'likely' recurrence of CFHR5 nephropathy were 16.6 and 52.9%, respectively; however, 76.5% of patients had a functional graft after a median of 120 months post-transplantation. Total recurrence was not associated with graft loss (P = 0.171), but was associated with the presence of microscopic haematuria (P = 0.001) and proteinuria (P = 0.018). Graft loss was associated with the presence of proteinuria (P = 0.025).

CONCLUSIONS

We describe for the first time the clinical characteristics and outcome of patients with CFHR5 nephropathy post-transplantation. Despite the recurrence of CFHR5 nephropathy, we provide evidence for a long-term favourable outcome and support the continued provision of kidney transplantation as a renal replacement option in patients with CFHR5 nephropathy.

A case of recurrent proliferative glomerulonephritis with monoclonal IgG deposits or de novo C3 glomerulonephritis after kidney transplantation

Proliferative glomerulonephritis with monoclonal immunoglobulin (Ig)G deposits (PGNMID) is a rare disease with a treatment that is not well established. Several cases of recurrent PGNMID after kidney transplantation have been documented, but almost all cases reported symptoms such as elevated serum creatinine and/or urinary protein levels; subsequently, episode biopsies were performed and a diagnosis was made. This is the case of a 27-year-old man who underwent living-donor kidney transplantation. The aetiology of renal failure was membranoproliferative glomerulonephritis type III, which had been diagnosed at the age of 9 years. Protocol biopsy performed on postoperative day 62 revealed isolated granular C3 deposits in the glomerular capillaries and mesangium. We reviewed the native kidney biopsy and confirmed IgG3 deposition alone, with strong glomerular staining for lambda light chains and negative staining for kappa light chains. Accordingly, we re-diagnosed the aetiology of his renal failure as PGNMID and suspected recurrent PGNMID in the early stage; therefore, we administered plasma exchange therapy. Thereafter, protocol biopsies were performed twice, which revealed persistent isolated C3 deposition; therefore, we made a diagnosis of recurrent PGNMID or C3 glomerulonephritis. Currently, the patient has normal renal function, with negative urine findings for >1 year. Here, we present the histological findings of consecutive allograft biopsies performed in this patient.

Proliferative glomerulonephritis with monoclonal immunoglobulin G deposits is associated with high rate of early recurrence in the allograft

The characteristics of allograft proliferative glomerulonephritis with monoclonal immunoglobulin G deposits (PGNMID) are not well defined. To better characterize this disease we retrospectively identified 26 patients with allograft PGNMID, including 16 followed with early protocol biopsies. PGNMID was found to be a recurrent disease in most (89%) patients. A diagnostic biopsy was done for proteinuria and/or increased creatinine in most patients. Median time from transplant to diagnostic biopsy was 5.5 months, with detection within three to four months post-transplant in 86% of patients. Mesangial proliferative glomerulonephritis was the most common pattern on the diagnostic biopsy with 89% of cases showing immunoglobulin G3 subtype restriction. A detectable serum paraprotein was present in 20% of patients. During a mean follow up of 87 months from implantation, 11 of 25 patients lost their allograft largely due to PGNMID within a mean of 36 months from diagnosis. Median graft survival was 92 months. Independent predictors of graft loss were a higher degree of peak proteinuria and longer time from implantation to diagnosis. Sixteen patients were treated with immunosuppressive therapy which resulted in over 50% reduction in proteinuria in 60%, and improvement of glomerular pathology in nine of 13 patients. However, 44% of responders subsequently relapsed. Thus, PGNMID has a high recurrence rate in renal allografts occurring early with detection enhanced by protocol biopsies. Graft outcome is guarded as nearly half of patients lose their graft within three years from diagnosis. Hence, there is a need for better treatment strategies for this disease.

Proliferative glomerulonephritis with monoclonal immunoglobulin G deposits complicated by immunoglobulin A nephropathy in the renal allograft

Immunoglobulin (Ig) A nephropathy (IgAN) is a known autoimmune disease due to abnormal glycosylation of IgA1, and occasionally, IgG co-deposition occurs. The prognosis of IgG co-deposition with IgAN is adverse, as shown in the previous studies. However, in the clinical setting, monoclonality of IgG co-deposition with IgAN has not been observed. We describe a case of proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) combined with IgAN in a renal allograft. A-21-year-old man developed end-stage renal failure with unknown aetiology and underwent living-donor kidney transplantation from his mother 2 years after being diagnosed. One year after kidney transplantation, proteinuria 2+ and haematuria 2+ were detected; allograft biopsy revealed mesangial IgA and C3 deposits, indicating a diagnosis of IgAN. After tonsillectomy and steroid pulse therapy, proteinuria and haematuria resolved. However, 4 years after transplantation, pedal oedema, proteinuria (6.89 g/day) and allograft dysfunction (serum creatinine (sCr) 203.3 µmol/L) appeared. A second allograft biopsy showed mesangial expansion and focal segmental proliferative endocapillary lesions with IgA1λ and monoclonal IgG1κ depositions. Electron microscopic analysis revealed a massive amount of deposits, located in the mesangial and subendothelial lesions. A diagnosis of PGNMID complicated with IgAN was made, and rituximab and plasmapheresis were added to steroid pulse therapy. With this treatment, proteinuria was alleviated to 0.5 g/day, and the allograft dysfunction recovered to sCr 132.6 µmol/L. This case suggests a necessity for investigation of PGNMID and IgA nephropathy in renal allografts to detect monoclonal Ig deposition disease.