Bridging the Divide: An Onco-Nephrologic Approach to the Monoclonal Gammopathies of Renal Significance

Daratumumab in the treatment of C3 glomerulopathy with monoclonal gammopathy: a case report and literature review

Although rare, C3 glomerulopathy (C3G) is increasingly recognized thanks to the currently available diagnostic skills. C3G is not a single disease but a group of disorders with distinct pathogenesis and progression. Thus, an essential step for its management remains an in-depth characterization of the specific form and the identification of underlying conditions, which may also impact treatment choices as well. Among these entities, an emerging condition is the association of C3G with monoclonal gammopathy, which confers poor outcomes. Overall, diagnosis of C3G remains challenging, and determining the appropriate treatment remains unclear. Conventional immunosuppressive therapy has proven ineffective in such cases, while clone-directed therapies have shown promising results in small interventional studies and case series. Here, we report a case of a patient affected by C3G with monoclonal gammopathy of renal significance who experienced rapid deterioration of kidney function requiring replacement therapy. After the failure of first-line treatment, a switch to the anti-CD38 therapy with daratumumab resulted in the progressive improvement of the patient's kidney function, leading to the discontinuation of hemodialysis after approximately 10 months. Serial renal biopsies were also performed to study the disease's evolution in response to the treatment. Based on the description of this single case, we have comprehensively reviewed available studies on daratumumab use in patients with C3G associated with monoclonal gammopathy to provide insights for the design of prospective studies which aim to enhance the management of such poor prognosis disease.

Contemporary Monoclonal Antibody Utilization in Glomerular Diseases

Therapeutic monoclonal antibodies (MAbs) have been one of the fastest growing drug classes in the past 2 decades and are indicated in the treatment of cancer, autoimmune disorders, solid organ transplantation, and glomerular diseases. The Food and Drug Administration has approved 100 MAbs between 1986 and 2021, and MAbs account for 20% of Food and Drug Administration's new drug approval every year. MAbs are preferred over traditional immunosuppressive agents because of their high specificity, reduced number of drug-drug interactions, and low toxicity, which make them a prime example of personalized medicine. In this review article, we provide an overview of the taxonomy, pharmacology, and therapeutic applications of MAbs in glomerular diseases. We searched the literature through PubMed using the following search terms: monoclonal antibodies, glomerular diseases, pharmacokinetics, pharmacodynamics, immunoglobulin, murine, chimeric,humanized, and fully human, and limited our search to years 2018-2023. We selected peer-reviewed journal articles with an evidence-based approach, prioritizing randomized control trials in specific glomerular diseases, if available. Advances in the MAb field have resulted in a significant paradigm shift in targeted treatment of immune-mediated glomerular diseases, and multiple randomized control trials are currently being conducted. Increased recognition is critical to expand their use in experimental research and personalized medicine.

Assessment of current clinical practice throughout the UK for the diagnosis and management of monoclonal gammopathy of renal significance

Since the inception of the term monoclonal gammopathy of renal significance (MGRS) in 2012 by the International Kidney and Monoclonal Gammopathy Research Group, there have been no consensus guidelines specifically pertaining to the UK regarding to patient management. We aimed to identify both regional and cross-discipline variation in current clinical practice, to provide insight and rationale for a potential standardised pathway in the future. A national survey of 88 consultants from the disciplines of haematology and nephrology was conducted between June 2020 and July 2021. Agreement was evident for aspects of the diagnostic pathway, including presenting features likely to raise suspicion of MGRS and the most pertinent confounding factors to consider before renal biopsy. However, significant variability was identified in both the cohort of diagnostic tests used, as well as urinary work-up for patients with suspected MGRS. Treatment and monitoring frequency was also an aspect of management identified as variable. Despite differences in clinical practice across the UK, MGRS diagnosis was widely regarded to be the joint responsibility of both disciplines. The results provide an indication of inter-regional and interdisciplinary differences in practice, highlighting the need for improved awareness and standardised protocol for management of MGRS that applies to the UK population.

Monoclonal gammopathy of renal significance: Multidisciplinary approach to diagnosis and treatment

Monoclonal gammopathy of renal significance (MGRS) is a hemato-nephrological term referring to a heterogeneous group of kidney disorders characterized by direct or indirect kidney injury caused by a monoclonal immunoglobulin (MIg) 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 (ESKD). The diagnosis is typically made by nephrologists through a kidney biopsy. Many distinct pathologies have been identified and they are classified based on the site or composition of the deposited Mig, or according to histological and ultrastructural findings. Therapy is directed towards the identified underlying clonal population and treatment decisions should be coordinated between hematologists and nephrologists in a multidisciplinary fashion, depend on the type of MGRS, the degree of kidney function impairment and the risk of progression to ESKD.

Rhabdomyolysis and Acute Renal Dysfunction as Initial Manifestations of Monoclonal Gammopathy of Renal Significance

Monoclonal gammopathy of renal significance (MGRS) is a rare heterogeneous group of kidney disorders that encompasses all disorders caused by deposition of monoclonal protein (M-protein) and its light or heavy chain fragments secreted by pre-malignant or non-malignant B-cell clones in patients who do not meet the diagnostic criteria for multiple myeloma (MM) or other B-cell malignancies. MGRS can manifest as glomerular diseases, tubulopathies, or vascular involvement with varying clinical presentations, making the diagnosis of MGRS challenging. In patients with high clinical suspicion based on preliminary blood and urine studies, the evaluation of MGRS begins with a renal biopsy followed by monoclonal studies and cytogenetic analysis. There is no standard treatment protocol for MGRS, and the current consensus suggests a clone-directed approach. If not identified and treated early, MGRS often results in poor outcomes and can lead to extrarenal manifestations, such as cardiogenic shock. Herein, we present a case involving a 43-year-old male with a rare presentation of rhabdomyolysis, rapidly progressing renal dysfunction, and cardiac dysfunction. A bone marrow biopsy did not meet the diagnostic criteria for MM or other B-cell malignancies, while a renal biopsy revealed Kappa light chain cast nephropathy, which led to the final diagnosis of MGRS.

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.

An Unusual Case of Acquired Angioedema and Monoclonal Gammopathy of Renal Significance in a Middle-Aged Caucasian Female

Acquired angioedema due to deficiency of C1 esterase inhibitor is also called acquired angioedema and is abbreviated as C1INH-AAE. It is a rare syndrome of recurrent episodes of angioedema, without urticaria, and in some patients, it is associated with B-cell lymphoproliferative disorders. Kidney involvement is rare in this condition. The monoclonal immunoglobulin secreted by a nonmalignant or premalignant B-cell or plasma cell clone, causing renal damage that represents a group of disorders which are termed as monoclonal gammopathy of renal significance (MGRS). In this article, we report a rare case of acquired C1 esterase deficiency angioedema and acute kidney injury with renal biopsy-proven MGRS. We present a 64-year-old Caucasian woman who presented with 2 weeks of recurring urticaria and new onset of acute kidney injury. She was diagnosed with monoclonal gammopathy–associated proliferative glomerulopathy through kidney biopsy, and serological workup came back positive for C1 esterase deficiency, implying acquired angioedema. Acquired angioedema is a rare disease with systemic involvement. Recurrent allergic manifestations and acute kidney injury should prompt MGRS as a differential.

Clinical Presentation, Renal Histopathological Findings, and Outcome in Patients with Monoclonal Gammopathy and Kidney Disease

Monoclonal gammopathies are associated with acute and chronic kidney injury. Nephrotoxicity of the secreted monoclonal (M)-protein is related to its biological properties and blood concentration. Little is known about epidemiology, clinical manifestations, and outcome of monoclonal gammopathies in patients with kidney disease. We retrospectively collected data about demographics, clinical manifestations, and renal histological lesions of all patients (n = 1334) who underwent kidney biopsy between January 2000 and March 2017. Monoclonal gammopathy was detected in 174 (13%) patients with a mean age of 66.4 ± 13.1 years. The spectrum of monoclonal gammopathies comprised monoclonal gammopathy of undetermined significate (MGUS) (52.8%), multiple myeloma (MM) (25.2%), primary amyloidosis (AL) (9.1%), smoldering MM (SMM) (4%), non-Hodgkin lymphoma (NHL) (6.8%), and Hodgkin lymphoma (HL) (1.7%). Monoclonal gammopathy of renal significance (MGRS) accounted for 6.5% in patients with MGUS and 14.2% in patients with SMM. Evaluation of kidney biopsy revealed that M-protein was directly involved in causing kidney injury in MM (93.1%). MM was the only gammopathy significantly associated with an increased risk of kidney injury (odds ratio [OR] = 47.5, CI 95%, 13.7–164.9; P ≤ 0.001). While there were no significant differences in the progression toward end-stage renal disease or dialysis (P = 0.776), monoclonal gammopathies were associated with a different risk of death (P = 0.047) at the end of the follow-up. In conclusion, monoclonal gammopathy was a frequent finding (13%) in patients who underwent kidney biopsy. M-protein was secreted by both premalignant (56.8%) and malignant (43.2%) lymphoproliferative clones. Kidney biopsy had a key role in identifying MGRS in patients with MGUS (6.5%) and SMM (14.2%). Among monoclonal gammopathies, only MM was significantly associated with biopsy-proven kidney injury. The rate of end-stage renal disease or dialysis was similar among monoclonal gammopathies, whereas NHL, MM, and SMM showed a higher rate of deaths.

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: Clinical and Histological Efficacy of a Bortezomib-Based Regimen

Monoclonal Gammopathy of Renal Significance (MGRS) is a group of heterogeneous disorders characterized by renal dysfunction secondary to the production of a monoclonal immunoglobulin by a nonmalignant B cell or plasma cell clone. We report the clinical and histological outcomes of two patients with biopsy-proven MGRS: one patient showed membranoproliferative glomerulonephritis with monoclonal k-light chain and C3 deposits, the second patient showed immunotactoid glomerulopathy. Both patients were treated with a 9-month chemotherapy protocol including bortezomib, cyclophosphamide, and dexamethasone. Renal biospy was repeated after 1 year. The estimated glomerular filtration rate (eGFR) increased from 22.5 (baseline) to 40 ml/min per 1.73 m2 after 12 months, then to 51.5 ml/min per 1.73 m2 after 24 months; proteinuria decreased from 4.85 (baseline) to 0.17 g/day after 12 months, then to 0.14 g/day after 24 months. Repeat renal biopsies showed a dramatic improvement of the glomerular proliferative lesions and near complete disappearance of the immune deposits. A bortezomib-based treatment proved very effective and was well-tolerated in the two patients presenting with clinically and histologically aggressive MGRS.

Pathophysiology and management of monoclonal gammopathy of renal significance

Recent years have witnessed a rapid growth in our understanding of the pathogenic property of monoclonal proteins. It is evident that some of these small monoclonal proteins are capable of inducing end-organ damage as a result of their intrinsic physicochemical properties. Hence, an umbrella term, monoclonal gammopathy of clinical significance (MGCS), has been coined to include myriad conditions attributed to these pathogenic proteins. Because kidneys are the most commonly affected organ (but skin, peripheral nerves, and heart can also be involved), we discuss MGRS exclusively in this review. Mechanisms of renal damage may involve direct or indirect effects. Renal biopsy is mandatory and demonstration of monoclonal immunoglobulin in kidney, along with the corresponding immunoglobulin in serum or urine, is key to establish the diagnosis. Pitfalls exist at each diagnostic step, and a high degree of clinical suspicion is required to diagnose MGRS. Recognition of MGRS by hematologists and nephrologists is important, because timely clone-directed therapy improves renal outcomes. Autologous stem cell transplant may benefit selected patients.

[Monoclonal gammapathy of renal significance (MGRS) at the current state: terminology, diagnosis and treatment]

In this article we discussed the current state of monoclonal gammapathy of renal significance (Monoclonal Gammopathy of Renal Significance MGRS) and revealed problems of B-cell clone secreting nephrotoxic monoclonal immunoglobulin identification. We followed 276 patients with monoclonal gammapathy including patients with non-amyloid nephropathy. The majority of patients had systemic AL-amyloidosis. We established better survival of the treated patients with systemic AL-amyloidosis in comparison with retrospective untreated cohort. We considered current treatment of patients with non-amyloid nephropathy and focused on the crucial role of multidisciplinary approach in management of these patients.

Multiple morphological phenotypes of monoclonal immunoglobulin disease on renal biopsy: Significance of treatment

Plasma cell dyscrasias frequently involve the kidney causing renal dysfunction. Multiple morphologic manifestations of κ light chain disease occurring simultaneously in the same kidney biopsy are uncommon and suggest local microenvironment effects in addition to structural properties of the light chain. A 61-year-old female presented with new onset renal failure and proteinuria. Serological workup revealed monoclonal gammopathy with elevated κ : λ ratio of 1,371. Renal biopsy revealed several paraprotein manifestations including κ light chain deposition disease, monoclonal fibrillary glomerulonephritis, cryocrystalglobulenemia and fibrillar/microtubular cast nephropathy. There was also incidental leukocyte chemotactic factor 2 amyloidosis (ALECT 2), negative for κ light chain and confirmed by immunohistochemistry (IHC). Bone marrow biopsy revealed 10 - 20% κ restricted plasma cells. The patient received 10 cycles of CyBorD (cyclophosphamide, bortezomib, and dexamethasone) chemotherapy. Renal function improved with decreased κ : λ ratio. Repeat bone marrow biopsy showed no evidence of abnormal plasma cells by IHC. The renal recovery demonstrates there may be response to chemotherapy irrespective of the morphologic manifestations of light chain-related injury. Additionally, if amyloid is not demonstrated to be of light chain origin, other amyloid types should be considered.

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.

Cyclophosphamide, bortezomib and dexamethasone (CyBorD): a promising regimen for renal light chain deposit disease

Renal light chain deposit disease is a rare disease with rapid progression to renal failure when left untreated. There is no standard treatment available. We present a unique case of renal IgA kappa deposit disease who developed severe decline in renal function within a few months of diagnosis. She was started on a single regimen of cyclophosphamide, bortezomib and dexamethasone (CyBorD) followed by maintenance treatment with bortezomib and dexamethasone leading to rapid improvement of renal function. This is the first case to be reported on renal IgA kappa deposit disease who have responded dramatically to CyBorD without the need for any modification of the regimen or stem cell transplant.

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.

Modern approaches to the detection of monoclonal gammopathy of undetermined significance (MGUS) in patients with kidney diseases

Monoclonal gammopathy (MG) is not only the state preceding of hematological neoplasms, but also associated with non - hematological diseases, in particular kidney damage. Aim. To assess the diagnostic value of “Freelite” methods in addition to electrophoresis (EF) and immunofixation (IF) of serum and urine proteins for detecting MG in patients with kidney diseases. Materials and methods. 87 patients with kidney damage, in which MG was established using the method of electrophoresis of serum proteins (EF), immunofixation (IF) and the method of free light chains determination - FLC “Freelite” were selected. The diagnostic value of three - component serum panel was compared with EF and IF. Results and discussion. AL-amyloidosis with kidney involvement was diagnosed in 41% patients, cryoglobulinemic glomerulonephritis (cryo GN) - in 18%, chronic glomerulonephritis (CGN) - in 35%, also there was small number of patients with light chain disease and cast - nephropathy. Determination of MG using EP was possible only in 38 (44%). Adding to the serum electrophoretic methods instead of the “Freelite” method, the urine EF and IF reduced the number of missed patients with monoclonal gammopathy from 24 (27%) to 11 (13%), including in the subgroup of patients with AL-amyloidosis but did not reach the sensitivity of the three - component serum screening panel. In 10 (11.5%) MG was represented only by intact mIg with one type of light chain, either κ or λ. Most often - in 25% of patients, intact monoclonal gammopathy was observed in HCV (+) cryo GN. A combination of intact mIgM, mIgG or mIgA with mFLC, was detected in 37 (42.5%). In almost half (46%) of the patients, only mFLC was detected - an abnormal κ/λ ratio. Conclusion: The serum screening panel EF + IF + “Freelite” spreads the low - grade monoclonal gammopathy recognition (MGUS) and should be included in the algorithm of examining patients with kidney disease.

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.

Complete biopsy-proven resolution of deposits in recurrent proliferative glomerulonephritis with monoclonal IgG deposits (PGNMIGD) following rituximab treatment in renal allograft

Background

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMIGD) is a disease entity classified under the group of “Monoclonal gammopathy-related kidney diseases”, and can recur after transplant. Clinical remission of proteinuria in patients with PGNMIGD has been previously shown following anti-B cell and/or anti-plasma cell therapies. Our case is the first to show complete histologic resolution of the glomerular monoclonal IgG kappa deposits in a case of recurrent PGNMIGD in renal allograft after rituximab and steroid treatment. This is a novel finding and it shows that the deposits are amenable to therapy. This case also highlights the importance of IgG subclass staining in the recognition of the monoclonal nature of the deposits. It is particularly important in PGNMIGD because only 20 to 30% of patients with this disease are reported to have detectable monoclonal gammopathy, and the deposits do not have any organized substructure on electron microscopic examination. Morphologically, they resemble polyclonal immune-type deposits seen in other immune complex glomerulonephritides such as lupus nephritis, infection-associated glomerulonephritis, and membranoproliferative glomerulonephritis (MPGN type I).

Case presentation

The patient is a 44 year old Caucasian male who received a living unrelated donor kidney transplant for end-stage renal disease diagnosed 7 years before transplant. The reported native kidney biopsy diagnosis was membranoproliferative glomerulonephritis (MPGN) with IgG, C3 and kappa restricted deposits. Fourteen months post-transplant, he presented with abrupt worsening of graft function, proteinuria and serum IgG kappa monoclonal spike. Allograft biopsy was consistent with recurrent PGNMIGD, considering the native kidney diagnosis and interval post-transplant. He underwent plasmapheresis, IV pooled immune globulin, steroid pulse and taper, and anti-CD-20 Rituximab therapy. Patient had gradual decline in proteinuria and complete resolution of the immune deposits on repeat biopsy 3 months later. Unfortunately he subsequently developed chronic antibody-mediated rejection and transplant glomerulopathy and graft failure 34 months post-transplant.

Conclusions

In a transplant setting, repeat allograft biopsies are frequently performed for graft dysfunction. This provides a good opportunity to study the evolution of the immune deposits following treatment. Our case shows complete histologic resolution of the deposits in allograft PGNMIGD.

Association of Monoclonal Gammopathy with Progression to ESKD among US Veterans

BACKGROUND AND OBJECTIVES

Whether patients with monoclonal protein are at a higher risk for progression of kidney disease is not known. The goal of this study was to measure the association of monoclonal protein with progression to ESKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a retrospective cohort study of 2,156,317 patients who underwent serum creatinine testing between October 1, 2000 and September 30, 2001 at a Department of Veterans Affairs medical center, among whom 21,898 had paraprotein testing within 1 year before or after cohort entry. Progression to ESKD was measured using linked data from the US Renal Data System.

RESULTS

Overall, 1,741,707 cohort members had an eGFR≥60 ml/min per 1.73 m2, 283,988 had an eGFR of 45-59 ml/min per 1.73 m2, 103,123 had an eGFR of 30-44 ml/min per 1.73 m2 and 27,499 had an eGFR of 15-29 ml/min per 1.73 m2. The crude incidence of ESKD ranged from 0.7 to 80 per 1000 person-years from the highest to lowest eGFR category. Patients with low versus preserved eGFR were more likely to be tested for monoclonal protein but no more likely to have a positive test result. In adjusted analyses, a positive versus negative test result was associated with a higher risk of ESKD among patients with an eGFR≥60 ml/min per 1.73 m2 (hazard ratio, 1.67; 95% confidence interval, 1.22 to 2.29) and those with an eGFR of 15-29 ml/min per 1.73 m2 (hazard ratio, 1.38; 95% confidence interval, 1.07 to 1.77), but not among those with an eGFR of 30-59 ml/min per 1.73 m2. Progression to ESKD was attributed to a monoclonal process in 21 out of 76 versus seven out of 174 patients with monoclonal protein and preserved versus severely reduced eGFR at cohort entry.

CONCLUSIONS

The detection of monoclonal protein provides little information on ESKD risk for most patients with a low eGFR. Further study is required to better understand factors contributing to a positive association of monoclonal protein with ESKD risk in patients with preserved and severely reduced levels of eGFR.

Proliferative glomerulonephritis with monoclonal immunoglobulin deposits of lambda chains

Increasingly, monoclonal gammopathies of renal significance (MGRS) are being described as unique, distinct disease states. We describe a type of MGRS with proliferative glomerular lesions with monoclonal immunoglobulin deposits of rarely reported IgG2 lambda chains.

Disease spectrum of abnormal serum free light chain ratio and its diagnostic significance

OBJECTIVE

To analyze the spectrum of abnormal serum free light chain ratio (sFLC κ/λ ratio), and to redefine the range of sFLC κ/λ ratio, so as to achieve hierarchical diagnosis of diseases with abnormal sFLC κ/λ ratio, resulting in the increased sensitivity and specificity in the diagnosis of monoclonal plasma diseases.

METHODS

Enrolled 1,340 patients with abnormal sFLC κ/λ ratio (<0.26 or >1.65) were grouped: (1) group A: malignant plasma diseases; (2) group B: monoclonal gammopathies of undetermined significance (MGUS); (3) group C: reactive plasma diseases. These patients were further divided by renal function eGFR <60 or >60 ml/min/1.73m2 to eliminate renal diseases influencing the results. Statistical analyses was performed by using SPSS 22 software.

RESULTS

When sFLC κ/λ ratio >3.49 and eGFR >60ml/min/1.73m2, the sensitivity and specificity of the diagnosis of malignant plasma diseases were 86.1% and 94.0%, respectively. When sFLC κ/λ ratio >2.89 and eGFR <60ml/min/1.73m2, the sensitivity and specificity of the diagnosis of malignant plasma diseases were 92.0% and 97.0%, respectively.

CONCLUSION

The sensitivity and specificity of the diagnosis of monoclonal plasma diseases can be significantly improved by redefining the cut-off value of sFLC κ/λ ratio and the renal function index of eGFR.

Monoclonal gammopathy of renal significance: Diagnostic workup

The clinical spectrum of diseases associated with monoclonal gammopathies is wide and they are most commonly the consequence of renal deposition of monoclonal immunoglobulin or its components. The differential diagnosis is difficult and renal biopsy is essential. To distinguish many of these pathologies is necessary to use techniques that are not always available, even in tertiary central hospitals. This review will discuss the clinical presentation, pathologic features, treatment, prognosis and common diagnostic difficulties of these entities.

Durable remission of C3 glomerulonephritis with mycophenolate mofetil

In C3 glomerulopathy, uncontrolled complement C3 activation via the alternative pathway results in glomerular C3 deposition and, in many cases, progressive renal failure. Despite advances in understanding of C3G pathogenesis over the last few years, there are no proven treatments. We describe a patient in whom C3 glomerulopathy was associated with renal impairment and elevated serum free kappa light chains. An initial response to corticosteroids was followed by relapse once steroids were weaned, prompting use of mycophenolate mofetil to maintain remission. We discuss some of the diagnostic and therapeutic issues surrounding C3G, including in the setting of monoclonal gammopathy.