De novo proliferative glomerulonephritis with monoclonal IgG deposits of the IgG1κ subtype in a kidney allograft

Rituximab Combined with Steroid and Tacrolimus Treats Proliferative Glomerulonephritis with Monoclonal IgG Deposits: A Case Report and Review of the Literature

INTRODUCTION

Due to the confounding heterogeneity, the therapeutic strategy for proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) remains to be defined.

CASE REPRESENTATION

We report a 38-year-old man with recurrent swelling of the eyelids and lower limbs, undergoing rituximab combined with steroid and tacrolimus treatment, who achieved an improved renal outcome. Underlying solid malignant tumours were excluded from the diagnosis.

DISCUSSION

We treated patients with rituximab along with steroids and tacrolimus. Improvements in proteinuria and renal function were observed. We also reviewed the current literature to assess the efficacy of rituximab in the treatment of PGNMID.

CONCLUSION

However, a larger pool of patients and a longer follow-up period are required to establish the role of rituximab and steroids in the treatment of PGNMID.

Poor outcomes of proliferative glomerulonephritis with monoclonal IgG deposits in renal allografts: a retrospective multicenter study

BACKGROUND

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) in renal allografts is a rare, renal-limited disease. No study has reported the long-term outcomes and prognostic features of PGNMID in renal allografts in the Chinese population.

METHODS

We retrospectively included transplant patients diagnosed with PGNMID who underwent renal allograft biopsy at three transplant centers from April 2012 to July 2020. We observed the clinicopathologic features, explored the long-term graft survival, and investigated the characteristics associated with the prognosis.

RESULTS

A total of 13 transplant patients with PGNMID were included, out of 3821 biopsies. The mean follow-up time was 55 months since kidney transplantation (KTx). At diagnosis, all patients presented with proteinuria (100%) and most of them with hematuria (92%). IgG3κ (69%) was the main immunofluorescence (IF) subtype. The median graft survival of the total cohort was 17 months from diagnosis and 49 months from kidney transplantation. During follow-up, 9 patients needed dialysis and 2 out of 9 patients who progressed to dialysis died of infection. Primary membranoproliferative glomerulonephritis (MPGN) (P = 0.014) and MPGN pattern at diagnostic biopsy (P < 0.001) were associated with a higher risk of graft loss.

CONCLUSIONS

The long-term outcome of allograft PGNMID was relatively poor in the Chinese population. Primary MPGN and MPGN pattern in renal allograft were associated with  poor outcomes.

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.

Monoclonal gammopathy of renal significance: clinical manifestation, pathogenic characteristic and treatment

Monoclonal gammopathy of renal significance (MGRS) is a group of renal disorders caused by a monoclonal immunoglobulin (MIg) secreted by a dangerous plasmatic/B-cell clone hyperplasia through MIg deposition or dysfunction of complement pathway, with increasing risk of progress to end stage renal disease (ESRD) and the underlying hematologic malignancy. The combination of renal biopsy, complete laboratory examination and bone marrow biopsy is an indispensable diagnostic tool for MGRS to identify accurately and unequivocally the pathogenic monoclonal MIg and provide guidance to treatment. Treatment of MGRS is composed of conventional therapy, chemotherapy, and stem cell transplantation to target the underlying clone and eliminate the noxious MIg on the basis of clinical data of some retrospective studies and a small amount of prospective trial. In addition, it is worthwhile point out assessment of therapeutic effect is significantly relevant for renal and overall prognosis. Thus, by comprehensively analyzing the clinical manifestations and pathogenic characteristic of MGRS, early recognition and prompt treatment can improve the prognosis and prevent post-translation recurrence with multidisciplinary cooperation.

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.

De novo glomerular diseases after renal transplantation: How is it different from recurrent glomerular diseases?

The glomerular diseases after renal transplantation can occur de novo, i.e., with no relation to the native kidney disease, or more frequently occur as a recurrence of the original disease in the native kidney. There may not be any difference in clinical features and histological pattern between de novo glomerular disease and recurrence of original glomerular disease. However, structural alterations in transplanted kidney add to dilemma in diagnosis. These changes in architecture of histopathology can happen due to: (1) exposure to the immunosuppression specifically the calcineurin inhibitors (CNI); (2) in vascular and tubulointerstitial alterations as a result of antibody mediated or cell-mediated immunological onslaught; (3) post-transplant viral infections; (4) ischemia-reperfusion injury; and (5) hyperfiltration injury. The pathogenesis of the de novo glomerular diseases differs with each type. Stimulation of B-cell clones with subsequent production of the monoclonal IgG, particularly IgG3 subtype that has higher affinity to the negatively charged glomerular tissue, is suggested to be included in PGNMID pathogenesis. De novo membranous nephropathy can be seen after exposure to the cryptogenic podocyte antigens. The role of the toxic effects of CNI including tissue fibrosis and the hemodynamic alterations may be involved in the de novo FSGS pathophysiology. The well-known deleterious effects of HCV infection and its relation to MPGN disease are frequently reported. The new concepts have emerged that demonstrate the role of dysregulation of alternative complement pathway in evolution of MPGN that led to classifying into two subgroups, immune complex mediated MPGN and complement-mediated MPGN. The latter comprises of the dense deposit disease and the C3 GN disease. De novo C3 disease is rather rare. Prognosis of de novo diseases varies with each type and their management continues to be empirical to a large extent.