Monoclonal gammopathy of renal significance: Diagnostic workup

Monoclonal gammopathy of renal significance (MGRS): Real-world data on outcomes and prognostic factors

Monoclonal gammopathy of renal significance (MGRS) is a recognized clinical entity. Literature regarding treatment and its outcomes in MGRS is sparse due to the rarity and misdiagnosis of MGRS. We retrospectively analyzed 280 adults with an MGRS diagnosis from 2003 to 2020 across 19 clinical centers from 12 countries. All cases required renal biopsy for the pathological diagnosis of MGRS. Amyloidosis‐related to MGRS (MGRS‐A) was present in 180 patients; nonamyloidosis MGRS (MGRS‐NA), including a broad spectrum of renal pathologies, was diagnosed in 100 patients. The median overall survival in the studied cohort was 121.0 months (95% CI: 105.0–121.0). Patients with MGRS‐A had a shorter overall survival than patients with MGRS‐NA (HR = 0.41, 95%CI: 0.25–0.69; p = 0.0007). Both hematologic and renal responses were associated with longer survival. Achievement of ≥VGPR was generally predictive of a renal response (OR = 8.03 95%CI: 4.04–115.96; p < 0.0001), one‐fourth of patients with ≥VGPR were renal nonresponders. In MGRS‐A, factors associated with poor prognosis included elevated levels of creatinine, beta‐2‐microglobulin, and hemodialysis at diagnosis. In MGRS‐NA, only age >65 years was associated with increased risk of death. Treatments provided similar hematologic response rates in both types of MGRS. Autologous stem cell transplantation led to better response than other treatments. This multicenter and international effort is currently the largest report on MGRS.

Bortezomib-containing regiment in treating glomerulopathy with fibronectin deposits combined with monoclonal gammopathy of undetermined significance: a case report and literature review

Background

Glomerulopathy with fibronectin deposits (GFND) is a newly recognized rare glomerular disease. As its onset can be stably inherited in affected families without sex differences and fibronectin 1 (FN1) mutations can be detected in 40% of patients’ families, GFND is considered to be an autosomal dominant genetic disease. The main clinical manifestations are proteinuria, progressive renal failure, edema, hypertension, hematuria, and type 4 renal tubular acidosis. The diagnosis was confirmed by renal biopsy, and there was no specific treatment. Monoclonal gammopathy refers to the existence of monoclonal immunoglobulin (MIg) produced by monoclonal plasma cells in serum. When MIg damages the kidney by direct deposition or indirect mechanisms, it is defined as monoclonal gammopathy of renal significance (MGRS). The principle of treatment is to inhibit plasma cells from producing MIg.

Case Description

We report the efficacy of a case of GFND combined with monoclonal gammopathy of undetermined significance (MGUS) treated with a bortezomib-containing regimen. A 44-year-old female patient was admitted to the hospital for “edema of both lower extremities for 1 month and aggravation for 5 days”. In May 2018, after exertion, the patient developed edema of both lower extremities, accompanied by foamy urine with no obvious deepening of urine color or decreased output, no gross hematuria, and gradual aggravation with fatigue.

Conclusions

After treatment, the edema of patient subsided, urinary protein decreased significantly, and serum albumin increased near to normal. It is achieving a very good therapeutic effect and long-term event-free survival. The treatment is safety and there are no obvious toxic side effects. It provides a new idea for the treatment of GFND.

Monoclonal gammopathy of renal significance: Early diagnosis is key

Monoclonal gammopathy of renal significance is a clinical-pathological entity grouping renal disorders secondary to the secretion of a monoclonal immunoglobulin synthesized by a B-cell-derived clone and/or plasma cells in a patient with no diagnostic criteria for multiple myeloma. This term applies to a concept recently introduced owing to the need to differentiate this entity from monoclonal gammopathy of undetermined significance, given the negative prognostic impact of its high morbidity and mortality resulting from both renal and systemic involvement, occasionally even progressing to advanced chronic kidney disease. The renal damage occurs via both direct pathogenic mechanisms, with the deposition of the monoclonal protein in different renal structures, as well as indirect mechanisms, acting as an autoantibody provoking dysregulation of the alternative complement pathway. The detection of this monoclonal protein and an early hematologic study are essential, as is the need for a kidney biopsy to establish the associated nephropathological diagnosis. Consequently, this then leads to the start of specific hematologic treatment to detain the production of the monoclonal protein and minimize renal and systemic injury.

Monoclonal gammopathy of renal significance: Early diagnosis is key

Monoclonal gammopathy of renal significance is a clinical-pathological entity grouping renal disorders secondary to the secretion of a monoclonal immunoglobulin synthesized by a B-cell-derived clone and/or plasma cells in a patient with no diagnostic criteria for multiple myeloma. This term applies to a concept recently introduced owing to the need to differentiate this entity from monoclonal gammopathy of undetermined significance, given the negative prognostic impact of its high morbidity and mortality resulting from both renal and systemic involvement, occasionally even progressing to advanced chronic kidney disease. The renal damage occurs via both direct pathogenic mechanisms, with the deposition of the monoclonal protein in different renal structures, as well as indirect mechanisms, acting as an autoantibody provoking dysregulation of the alternative complement pathway. The detection of this monoclonal protein and an early hematologic study are essential, as is the need for a kidney biopsy to establish the associated nephropathological diagnosis. Consequently, this then leads to the start of specific hematologic treatment to detain the production of the monoclonal protein and minimize renal and systemic injury.

Proliferative glomerulonephritis with monoclonal immunoglobulin deposits: Successful treatment for new and rare entity

Proliferative glomerulonephritis with monoclonal immunoglobulin deposits is a new disorder with undefined treatment modalities. We propose cyclophosphamide-bortezomib-dexamethasone and autologous stem cell transplantation as a therapeutic protocol.

The clinical implication of monoclonal gammopathies: monoclonal gammopathy of undetermined significance and of renal significance

Monoclonal gammopathy of renal significance (MGRS) has introduced a new perspective to several well-known disease entities impacting nephrology, haematology and pathology. Given the constantly changing disease spectrum of these entities, it is clinically imperative to establish diagnostic and treatment pathways supported by evidence-based medicine. MGRS is a disease of the kidney, secondary to plasma cell clonal proliferation or immune dysfunction, requiring therapeutic intervention to eradicate the offending clone. To fully understand the disease(s), it is prerequisite to determine the significance of the findings. The diagnostic work up should be extensive due to the wide heterogeneity of clinical presentation, ultimately necessitating kidney biopsy. Particular patient profiles such as AL amyloidosis, which may be diagnosed through biopsies of other tissues/organs, may be an exception. Treatment decisions should be formulated by multi-disciplinary consensus: nephrologists, haematologists and pathologists. The ultimate goal in managing MGRS is eradication of the offending plasma cell clone which requires targeted chemotherapy and, in eligible cases, haematopoietic stem cell transplantation. We present a review of diagnostic procedures, treatment options and advances in the last few years in the management of MGRS in an effort to acquaint specialists with this new face of several older diseases.

Bortezomib-Based Chemotherapy with Autologous Stem Cell Transplantation for Monoclonal Gammopathy of Renal Significance: A Case Report and Literature Review

BACKGROUND/AIMS

The term monoclonal gammopathy of renal significance (MGRS) was introduced in 2012 to emphasize kidney lesions in monoclonal gammopathy patients. Bortezomib-based chemotherapy has become the first-line treatment for MGRS.

OBJECTIVES

The objective of this study was to investigate whether the strategy of combining chemotherapy with autologous stem cell transplantation (ASCT) could improve prognosis and decrease functional kidney impairment in patients with MGRS.

METHODS

We reported the case of a 44-year-old Asian patient who was diagnosed with MGRS and received 5 cycles of Velcade® (a trade name for bortezomib), thalidomide, and dexamethasone therapy (VTD therapy), and subsequently underwent ASCT. In addition, we performed a literature review and summarized the latest advances in the characterization, treatment, and prognosis of MGRS.

RESULTS

The patient was diagnosed with light chain deposition disease by renal biopsy. After 5 cycles of VTD therapy, the patient had a very good partial response characterized by the resolution of M-protein (20.2% before treatment vs. 2.5% after treatment), remission of the level of serum free lambda (FLAM; over 80% decline), and normalization of the serum free light chain (sFLC) ratio (κ to λ). He also had a renal response characterized by a decreased serum creatinine level (1.61 vs.1.34 mg/dL) and less severe proteinuria (6.77 g/24 h vs.1.264 g/24 h) after chemotherapy. Importantly, after ASCT, the patient achieved a complete response (CR) characterized by a negative serum immunofixation electrophoresis (IFE) result and a dramatic decrement in FLAM (over 90%). Furthermore, 6 months after ASCT, the patient still remained in stable condition with a negative IFE result, normal sFLC ratio, and low level of serum creatinine (1.31 mg/dL) and proteinuria (0.339 g/24 h). In our retrospective literature analysis, we found that MGRS patient survival time and renal outcome had been markedly improved by current therapies due to the popularization of bortezomib-based chemotherapy and ASCT.

CONCLUSIONS

The patient successfully achieved CR after VTD therapy followed by ASCT. However, this treatment is controversial, and a standard therapy recommendation for MGRS has not been established. Bortezomib-based chemotherapy combined with ASCT may have prospects for the treatment of MGRS, but the exact effects of ASCT remain unclear and should be thoroughly investigated.

Henoch-Schönlein purpura nephritis associated with monoclonal gammopathy of renal significance: a case report

Monoclonal gammopathy of renal significance (MGRS) can present with different morphologic features and lead to kidney failure. The Henoch-Schönlein purpura nephritis (HSPN) that cannot be relieved by treatment with glucocorticoid and immunosuppressive agents suggests the presence of monoclonal gammopathy in adult patients. The present study reports on a single case of HSPN associated with IgA-κMGRS. The patient who suffered from recurrent skin purpura for 6 months and nephrotic syndrome for 2 months was admitted to our hospital. Bone marrow biopsy showed monoclonal gammopathy of undetermined significance. Kidney biopsy indicated a Henoch-Schönlein purpura nephritis (HSPN, ISKDC classified as type III) with positive staining with κ-light chain in the glomeruli and renal tubular epithelial cells. Furthermore, skin biopsy showed leukocytoclastic vasculitis and negative staining for Congo red and light chain. Given both the renal and cutaneous involvement, the patient was considered to have HSPN associated with IgA-κMGRS. The patient experienced an exacerbation in his purpura-like lesions and clinical status after treatment with glucocorticoid and immunosuppressive agents. Consequently, the patient was put on a regimen that included dexamethasone (20 mg on the 1st, 4th, 8th, and 11th days of each month, iv) and bortezomib (2.4 mg on the 1st, 4th, 8th, and 11th days of each month, iv). Eight weeks after treatment, he had complete resolution of his cutaneous purpura and his biochemical parameters improved. The latent presence of MGRS in cases of HSPN should be considered in adult patients. Increased cognizance and correct treatment options could improve patient outcomes.

Lenalidomide as a Beneficial Treatment Option for Renal Impairment Caused by Light Chain Deposition Disease

Light chain deposition disease (LCDD) is a rare systemic disorder caused by the deposition of light chain immunoglobulins, which often results in renal impairment associated with either nephrotic syndrome or asymptomatic proteinuria. B-cell neoplasms, such as multiple myeloma and lymphoproliferative disorders, are well-known underlying diseases in LCDD. Some chemotherapy regimens have been reported, but both evidence-based treatment and management for LCDD have yet to be established. We herein report three cases of LCDD treated with lenalidomide-based therapy, resulting in hematologic responses accompanied by a significant reduction in proteinuria and improvement in the renal function. We recommend lenalidomide-based therapy for renal impairment caused by LCDD.

Monoclonal gammopathy of renal significance (MGRS) increases the risk for progression to multiple myeloma: an observational study of 2935 MGUS patients

Purpose

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignancy preceding multiple myeloma (MM) or related disorders. In MGUS, renal impairment caused by deposition of the monoclonal immunoglobulins or free light-chains monoclonal gammopathy of renal significance (MGRS) is often associated with high morbidity and mortality. We analysed the prevalence of renal impairment, clinical features and the long-term outcome in 2935 patients with MGUS.

Methods

Between 1/2000 and 8/2016, 2935 adult patients with MGUS were identified in our database.

Results

In 44/2935 (1.5%) patients MGRS was diagnosed. In MGRS patients, significantly more progressions to MM were observed than in MGUS patients (18% vs. 3%; P<0.001). MGRS patients showed a higher risk for progression (HR 3.3 [1.5-7.4]) in the Cox model. Median time to progression was 23 years for MGUS and 18.8 years for MGRS patients. Corresponding progression rate was 8.8 [7.2-10.7] per 1000 patient-years (py) for MGUS patients and 30.6 [15.3–61] for the MGRS group. Risk for progression within the first year after diagnosis was 1% [0.6-1.4] in the MGUS group and 10% [4-29] among MGRS patients.

Conclusion

The significantly higher risk for progression to MM means MGRS patients should be monitored carefully and treated in a specialized centre.