Proliferative glomerulonephritis with monoclonal IgG2κ deposit successfully treated with steroids: a case report and review of the literature

Discordance of light chain isotypes between serum and glomerular deposits in proliferative glomerulonephritis with monoclonal IgG deposits: a case report and review of the literature

BACKGROUND

Proliferative glomerulonephritis with monoclonal immunoglobulin G (IgG) deposits (PGNMID) is a disease entity with nonorganized granular glomerular deposition with monoclonal proteins of both heavy and light chains. Dysproteinemia was observed in only 30% of the patients with PGNMID. We herein report a case of PGNMID with discrepancy between serum and glomerular deposits.

CASE PRESENTATION

The patient was a 50-year-old man who had been followed at a local clinic due to hypertension, type 2 diabetes, hyperlipidemia, hyperuricemia, fatty liver, and obesity. Proteinuria had been noted five years previously, and he had been referred to a hematology department due to hyperproteinemia, high gamma globulin, and κ Bence-Jones protein (BJP) positivity one year previously. Bone marrow aspiration showed 5% plasma cells, and he was referred to the nephrology department to evaluate persistent proteinuria. He was hypertensive, and his estimated glomerular filtration rate was 54.2 ml/min/1.73 m2. His urinary protein level was 0.84 g/g⋅Cr. Urine and serum immunofixation showed BJP-κ type and IgG-κ type, respectively. Kidney biopsy showed an increase in mesangial cells and matrix without nodular lesions under a light microscope. Immunofluorescence microscopy showed granular deposits of IgG and C3 on the capillary wall and weak positivity for C1q. IgG3 was predominant among the IgG subclasses, and intraglomerular κ and λ staining was negative for κ and positive for λ. Direct fast scarlet staining was negative. Electron microscopy showed lumpy deposits without a fibrillar structure in the subepithelial area. Based on the above findings, a diagnosis of membranous nephropathy-type PGNMID was made. Since proteinuria increased gradually after three years of treatment with valsartan (40 mg, daily), oral prednisolone (30 mg, daily) was initiated, which led to decreased proteinuria. The dose of oral prednisolone was gradually tapered to 10 mg per day. At that time, proteinuria was 0.88 g/g⋅Cr. We found 204 cases in 81 articles in the PubMed database, among which 8 showed discrepancy in the heavy and/or light chains between serum and kidney.

CONCLUSIONS

We experienced a case of membranous nephropathy-type PGNMID with discrepancy in light chains between serum and kidney that was successfully treated with oral prednisolone.

A rare case of proliferative glomerulonephritis with monoclonal IgG2 kappa deposit: a case report

BACKGROUND

Proliferative glomerulonephritis with monoclonal immunoglobulin G (IgG) deposits (PGNMID) is a rare monoclonal gammopathy of renal significance with dense deposits of monoclonal immunoglobulin.

CASE PRESENTATION

We report a 78-year-old Japanese male patient with mild proteinuria and lower extremity edema. Monoclonal immunoglobulin could not be identified in his serum or urine. Although his bone marrow biopsy was negative, renal biopsy found features of membranoproliferative glomerulonephritis (MPGN) with deposition of monoclonal IgG2 kappa. Electron microscopy examination revealed non-organized electron-dense deposits in the subepithelial, and subendothelial mesangial regions. Steroid monotherapy was performed after diagnosis of PGNMID but complete remission was not achieved.

CONCLUSION

PGNMID with IgG3 kappa deposits is the most common in cases with the histological feature of MPGN. There are few cases of PGNMID with IgG2 kappa deposits exhibiting MPGN. This report describes a very rare case of PGNMID with the histological feature of MPGN.

A case of proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) that responded favorably to steroid therapy

Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) generally has a poor prognosis and the consensus is that it needs to be treated with clone-directed therapy. However, the prognosis of PGNMID is heterogenous and some cases have been successfully treated using other therapeutic strategies. We herein report a case of PGNMID that responded favorably to steroids without clone-directed therapy. An 18-year-old woman was referred to a nephrologist with proteinuria detected in an annual health check-up. Over a 3-year period, the concentration of creatinine (Cr) increased from 0.76 to 1.00 mg/dL and proteinuria from 0.35 to 1.9 g/g Cr. Monoclonal gammopathies were not detected in her serum or urine. Based on the findings of kidney biopsy at the age of 21 years, the patient was diagnosed with proliferative glomerulonephritis with monoclonal IgG1-kappa deposits. The histological feature was mesangial proliferative glomerulonephritis with advanced glomerulosclerosis, which is a rare presentation of PGNMID. Intravenous methylprednisolone pulse therapy was initiated, followed by oral prednisolone at a dose of 30 mg daily. One year later, a second kidney biopsy revealed a significant decrease in mesangial deposits of IgG1-kappa. Prednisolone was gradually tapered and discontinued 2 years after the first kidney biopsy. At the time of prednisolone withdrawal, urinalysis showed proteinuria of 0.2 g/g Cr without hematuria. Kidney function remained stable throughout the treatment period.

Steroid-sensitive recurrent mesangial proliferative glomerulonephritis with monoclonal IgG deposits

Proliferative glomerulonephritis with monoclonal immunoglobulin G (IgG) deposits (PGNMID) is a rare kidney disease. The predominant pathological finding of PGNMID is the presence of monoclonal Ig deposits on the glomerular basement membrane (GBM). However, there is some variation in deposition pattern in this kidney disease. We report a case of steroid-sensitive recurrent mesangial proliferative type of PGNMID. A 40-year-old female noticed lower leg pitting edema and polyuria. Approximately 10 days prior to the first clinic visit, she was diagnosed with nephrotic syndrome based on the laboratory data of urine and blood. Immunological and hematological examination revealed no abnormality. However, kidney biopsy specimens showed mild mesangial cell proliferation and mesangial matrix accumulation on light microscopic findings. Regarding immunofluorescence staining, granular deposits of IgG, C1q, and β1c were observed on GBM and mesangial area. Granular deposits of IgG3 and λ were also observed on GBM and mesangial area. Moreover, negative results were obtained for the phospholipase A2 receptor antibody and thrombospondin type-1 domain-containing 7A. Electron microscopy revealed highly electron dense deposits mainly in the mesangial region. Kidney biopsy showed mesangial proliferative glomerulonephritis characterized by monoclonal Ig deposition of IgG3/λ. Steroid therapy was initiated, and complete remission was achieved on day 36. After the discontinuation of steroid therapy, proteinuria recurred and second kidney biopsy findings were almost similar to the first biopsy. However, complete remission was achieved with steroid therapy. This is a rare recurrent case of steroid-sensitive PGNMID. The pathological feature of this case was mesangial proliferative glomerulonephritis with Ig deposition of IgG3/λ.

An update to the pathogenesis for monoclonal gammopathy of renal significance

Monoclonal gammopathy of renal significance (MGRS) is characterized by the nephrotoxic monoclonal immunoglobulin (MIg) secreted by an otherwise asymptomatic or indolent B-cell or plasma cell clone, without hematologic criteria for treatment. The spectrum of MGRS-associated disorders is wide, including non-organized deposits or inclusions such as C3 glomerulopathy with monoclonal glomerulopathy (MIg-C3G), monoclonal immunoglobulin deposition disease, proliferative glomerulonephritis with monoclonal immunoglobulin deposits and organized deposits like immunoglobulin related amyloidosis, type I and type II cryoglobulinaemic glomerulonephritis, light chain proximal tubulopathy, and so on. Kidney biopsy should be conducted to identify the exact disease associated with MGRS. These MGRS-associated diseases can involve one or more renal compartments, including glomeruli, tubules and vessels. Hydrophobic residues replacement, N-glycosylated, increase in isoelectric point in MIg causes it to transform from soluble form to tissue deposition, causing glomerular damage. Complement deposition is found in MIg-C3G, which is caused by an abnormality of the alternative pathway and may involve multiple factors including complement component 3 nephritic factor, anti-complement factor auto-antibodies or MIg which directly cleaves C3. The effect of transforming growth factor beta and platelet-derived growth factor-β on mesangial extracellular matrix is associated with glomerular and tubular basement membrane thickening, nodular glomerulosclerosis, and interstitial fibrosis. Furthermore, inflammatory factors, growth factors and virus infection may play an important role in the development of the diseases. In this review, for the first time, we discussed current highlights in the mechanism of MGRS-related lesions.

An update to the pathogenesis for monoclonal gammopathy of renal significance

Monoclonal gammopathy of renal significance (MGRS) is characterized by the nephrotoxic monoclonal immunoglobulin secreted by an otherwise asymptomatic or indolent B cell or plasma cell clone, without hematologic criteria for treatment. These MGRS-associated diseases can involve one or more renal compartments, including glomeruli, tubules, and vessels. Hydrophobic residue replacement, N-glycosylated, increase in isoelectric point in monoclonal immunoglobulin (MIg) causes it to transform from soluble form to tissue deposition, and consequently resulting in glomerular damage. In addition to MIg deposition, complement deposition is also found in C3 glomerulopathy with monoclonal glomerulopathy, which is caused by an abnormality of the alternative pathway and may involve multiple factors including complement component 3 nephritic factor, anti-complement factor auto-antibodies, or MIg which directly cleaves C3. Furthermore, inflammatory factors, growth factors, and virus infection may also participate in the development of the diseases. In this review, for the first time, we discussed current highlights in the mechanism of MGRS-related lesions.

Proliferative glomerulonephritis with monoclonal immunoglobulin deposits: a nephrologist perspective

Proliferative glomerulonephritis (GN) with monoclonal immunoglobulin deposits (PGNMIDs) is a recently described entity among the spectrum of monoclonal gammopathy of renal significance (MGRS). The disease is renal limited and manifests with chronic glomerular disease, altered renal function and albuminuria, sometimes in the nephrotic range. Acute nephritic syndrome is rare. PGNMID occurs mostly in the sixth decade, but it may affect young adults. Histologically, PGNMID is characterized predominantly by membranoproliferative GN and less frequently by diffuse endocapillary GN, mesangioproliferative GN or atypical membranous GN. Immunofluorescence and electron microscopic studies are the cornerstone of diagnosis, showing granular deposits involving glomeruli only, and composed of monotypic immunoglobulin G (IgG), with a single heavy chain subclass (most commonly IgG3) and light chain (LC) restriction (usually κ), admixed with complement deposits. PGNMID variants with monotypic LC-only, IgA or IgM deposits are uncommon. Ultrastructurally, deposits are amorphous with predominant subendothelial and mesangial distribution. PGNMID should be distinguished from type 1 cryoglobulinemic GN and immunotactoid GN, which share some common pathological features. Contrary to other MGRS lesions, the rate of detection of the nephrotoxic monoclonal Ig in the serum or urine, and of an abnormal bone marrow B-cell clone, is only ∼30%. Renal prognosis is poor, with progression to end-stage renal disease in 25% of patients within 30 months and frequent early recurrence on the renal allograft. The pathophysiology of PGNMID is unclear and its treatment remains challenging. However, recent studies indicate that clone-targeted chemotherapy may significantly improve renal outcomes, opening future perspectives for the management of this rare disease.

An IgA1-lambda-type monoclonal immunoglobulin deposition disease associated with membranous features in a patient with IgG4-related kidney disease: a case report

BACKGROUND

IgG4-related disease (IgG4-RD) is a newly recognized fibroinflammatory condition. The kidney is one of the organs commonly affected by IgG4-RD. Tubulointerstitial nephritis (TIN) is the main feature, and membranous nephropathy (MN) has also been described frequently. In MN, polyclonal immunoglobulins and complements are deposited in granular form along the glomerular basement membranes (GBMs). Unusual cases of monoclonal immunoglobulin deposition disease (MIDD) associated with membranous features have been reported. MIDD is morphologically similar to MN but contains immunoglobulins considered to be derived from single B-cell clone.

CASE PRESENTATION

We describe a 65-year-old man who was referred to our hospital because of hyperproteinaemia, eosinophilia, anaemia, and proteinuria. A renal biopsy demonstrated infiltration of plasma cells and eosinophils in the interstitium, and the ratio of IgG4-positive plasma cells to IgG-positive plasma cells was 55%. The patient was diagnosed as having IgG4-related TIN. Periodic acid methenamine silver staining under light microscopy revealed a bubbling appearance and spike formation in the GBM. On immunofluorescence, the expression of IgG and complements was negative; however, IgA was positively expressed in a granular pattern along the GBM. An IgA subclass analysis revealed a significant deposition of IgA1-lambda (IgA1-λ). Electron microscopy revealed irregular and small non-organized and non-Randall-type granular electron-dense deposits in the GBM that were shaped like snow leopard spots.

CONCLUSIONS

After corticosteroid therapy was initiated, the patient's eosinophilia remarkably improved and his serum creatinine, IgG, and IgG4 levels decreased to within the normal ranges. However, massive proteinuria persisted. To our knowledge, this is the first reported case of IgG4-related TIN associated with IgA1-λ-type MIDD with membranous features.

Concurrent isolated IgG2-positive membranous nephropathy and malignant B-cell lymphoma

A recent systematic review showed that hematological malignancy is often complicated by membranous nephropathy (MN). Histologically, the deposition of IgG subclasses other than IgG4 may imply secondary MN, such as malignancy-associated MN (M-MN). We describe a very rare case of concurrent isolated IgG2-positive MN and B-cell lymphoma. An 83-year-old woman was hospitalized at our institute for facial and lower extremity edema persisting for 2 months. Laboratory tests showed urinary protein level of 10.8 g/day, serum albumin level of 1.6 g/dl, and serum creatinine level of 2.34 mg/dl. Soon after diagnosis of nephrotic syndrome, treatment with corticosteroid was initiated, but it proved to be ineffective. Renal biopsy showed isolated IgG2-positive MN with highly infiltrated CD20-positive lymphoid cells in the kidney. Computed tomography revealed systemic lymphadenopathy, and aberrant B-cells with immunoglobulin light chain restriction were detected in peripheral blood and bone marrow, which led to the diagnosis of mature B-cell lymphoma. Although rituximab (375 mg/m²/week) was administered, the patient suddenly died from gastrointestinal bleeding on day 40 of hospitalization. It is, thus, necessary to consider hematological malignancy when a diagnosis of MN is made. Further studies are expected to elucidate the pathogenesis and to help establish the adequate treatment for this rare situation.

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.

Proliferative glomerulonephritis with monoclonal IgG deposits in two kidney allografts successfully treated with rituximab

Proliferative glomerulonephritis with monoclonal immunoglobulin G deposit (PGNMID), a recently described pathologic entity in native kidneys, has been recognized in kidney transplant patients, where it can present as either recurrent or de novo disease. There is no definitive treatment to date, in either population. Here, we present two cases of PGNMID in kidney allografts that illustrate the challenges of diagnostic approach and highlight the allograft outcome after treatment with rituximab as a potential treatment of this condition.

Proliferative glomerulonephritis associated with monoclonal immune deposits: A case report and review of literature

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) is a newly recognized entity caused by monoclonal deposition of IgG. PGNMID resembles immune complex glomerulonephritis (GN) on light and electron microscopy. The monotypic immunoglobulin deposits seen on immunofluorescence (IF) clinches the diagnosis. We report a case of proliferative GN associated MGRS and review the relevant literature. The patient had significant proteinuria and elevated serum creatinine. The renal biopsy showed proliferative GN with focal crescents and monoclonal immune deposits confirming a diagnosis of PGNMID. Serum work up showed no monoclonal proteins. Proliferative GN as a manifestation of a monoclonal gammopathy needs to be borne in mind especially in renal biopsies of older patients.