Clinical features, predictors of disease progression and results of renal transplantation in fibrillary/immunotactoid glomerulopathy

Fibrillary Glomerulonephritis and Multiple Myeloma: A Case Report and Literature Review

Introduction

Fibrillary glomerulonephritis (FGN) is a rare form of immune complex-mediated primary glomerular disease frequently coexisting with malignancies or autoimmune diseases. The kidney prognosis is extremely poor, with approximately 50% of patients progressing to end-stage kidney disease within 2-4 years after diagnosis. However, no established treatment currently exists.

Case Presentation

Here we describe a rare case of FGN diagnosed in a patient progressing from monoclonal gammopathy to multiple myeloma. The histopathological findings of the kidney biopsy were consistent with classical FGN and revealed no evidence of myeloma cast nephropathy. Albumin-dominant, Bence Jones protein-negative proteinuria further supported this diagnosis. The patient was successfully treated with anti-myeloma chemotherapies including autologous stem cell transplant, resulting in significant improvement in kidney function.

Conclusion

Based on our experience, secondary FGN associated with plasma cell neoplasms may represent a rare entity that responds favorably to anti-myeloma therapies. Initial investigations to rule out coexistent plasma cell neoplasms are crucial for the optimal management of FGN patients.

Fibrillary Glomerulonephritis with Prevalent IgA Deposition Associated with Psoriasis

Fibrillary and immunotactoid glomerulonephritis represent the pathological entities characterized by structured fibrillary/microtubular deposits, whose identification is possible only by electron microscopy. We report a 46-year-old female who presented with proteinuria 15 years after the onset of psoriasis. Diffuse global glomerulosclerosis pattern was noted on light microscopy. In immunofluorescence microscopy, predominant IgA deposition was observed and electron microscopy showed organized randomly arranged fibrillary deposits with diameter ranging between 10 and 23 nm in mesangial, subendothelial, intramembranous, and subepithelial sites.

Glomerulopathies with Fibrillary Deposits

The glomerulopathies associated with the deposition of extracellular fibrils in the glomeruli are subdivided into Congo red positive (amyloidosis) and Congo red negative (non-amyloidotic glomerulopathies) based on Congo red staining. The non-amyloidotic glomerulopathies are divided into immunoglobulin-derived and non-immunoglobulin-derived glomerulopathies. The immunoglobulin-derived glomerulopathies: fibrillary glomerulopathy (FGn) and immunotactoid glomerulopathy (ITG) are rare glomerulopathies. The diagnosis of fibrillary-immunotactoid glomerulopathy depends on electron microscopy, which shows the presence of microfibrils in the glomeruli. The microfibrils in FGn are randomly arranged with diameters less than 30 nm. The microfibrils in ITG are larger than 30 nm with a visible lumen (microtubules), focally arranged in parallel bundles. Patients with fibrillary-immunotactoid glomerulopathy present with proteinuria (usually in the nephrotic range), microscopic hematuria, arterial hypertension, and chronic kidney disease that progresses to kidney failure over months to years. Currently, there are no guidelines for the treatment of fibrillary-immunotactoid glomerulopathy, although immunotactoid glomerulopathy could be associated with underlying hematologic disorders with the need for clone-directed therapy.

A Rare Case of Recurrent Immunotactoid Glomerulonephritis

Immunotactoid glomerulopathy is an uncommon cause of glomerular disease that results from deposits derived from immunoglobulins. This rare disease can occur in native kidneys and in transplant patients. They are present only in 0.5% to 1.4% of native kidney biopsies. Treatment of this disease is directed at the underlying monoclonal gammopathy, infection, and B-cell lymphoproliferative disorders. Prognosis is very guarded with 50% of people developing ESRD within five years of diagnosis. We present an interesting, rare case of recurrent immunotactoid glomerulonephritis which responded appropriately to rituximab therapy.

Clinicopathologic features and treatment outcomes of patients with fibrillary glomerulonephritis: A case series

ABSTRACT

Fibrillary glomerulonephritis (FGN) is a diverse glomerular disease with poor renal prognosis. The optimal therapeutic approach remains undetermined, as treatment outcomes vary across different studies.We retrospectively reviewed the medical data of 10 patients diagnosed with biopsy-proven FGN at our center between 2004 and 2019. Clinical and histological features, as well as therapeutic regimens and treatment response, are reported.The patients were predominantly men (2.5/1 men-female ratio) with a mean age at diagnosis of 46.5 years (IQR: 41.5-59.5). The median proteinuria and creatinine levels at presentation were 2.55 g/day (IQR: 0.4-8.9) and 1.35 mg/dl (IQR: 0.94-1.88), respectively. Four out of 10 patients presented with nephrotic syndrome, 5 patients with nephritic syndrome and 1 with isolated microscopic hematuria. Light microscopy showed mesangial proliferative (n = 7), membranoproliferative-like (n = 2), and diffuse sclerosing patterns (n = 1). Rituximab was used in 7/10 patients, either as monotherapy (n = 3) or combined with cyclophosphamide and corticosteroids (n = 4). Patients who were treated with immunosuppression had higher median levels of creatinine (1.40 mg/dl) and proteinuria (3.5 g/d) compared to those who received supportive treatment alone (0.94 mg/dl and 0.6 g/d, respectively). After a median follow-up of 30 months (IQR:18-66.5), 4 out of 7 patients (57%) treated with immunosuppression achieved a clinical response, 1 had persistent renal dysfunction and 2 patients progressed to end-stage renal disease.The present case series extends the existing literature on the clinical features and outcomes of FGN, as well as the use of rituximab-based regimens for the treatment of the disease. Further research is needed to establish the proper management of the disease.

DNA J homolog subfamily B member 9 and other advances in fibrillary glomerulonephritis

PURPOSE OF REVIEW

Fibrillary glomerulonephritis (FGN) involves ∼1% of native kidney biopsies and is characterized by glomerular deposition of fibrils larger than amyloid (12-24 nm diameter) composed of polyclonal immunoglobulin G (IgG). The recent discovery of DNA J homolog subfamily B member 9 (DNAJB9) in FGN glomerular deposits has contributed a specific and sensitive biomarker, informing morphologic classification and pathogenesis. This review will consider contemporary FGN incidence and genetics, pathogenesis, (lack of) paraprotein association, variants, treatment, and transplantation.

RECENT FINDINGS

DNAJB9 tissue assays have enabled the identification of morphologic variants and improved classification of fibrillary-like glomerular diseases. Together with paraffin immunofluorescence and IgG subclass studies, these have established that FGN is only rarely monoclonal and these patients usually do not have an monoclonal gammopathy. The discovery of DNAJB9 opens new avenues of investigation into FGN pathogenesis, especially those of the unfolded protein response. Treatment for FGN remains empiric, with some encouraging data on rituximab-based therapy. Transplantation is a good option for patients progressing to end-stage kidney disease.

SUMMARY

Advances building on the discovery of DNAJB9 in FGN should lead to long-term evolution in targeted treatment and outcome of this glomerular disease.

Results of a nation-wide cohort study suggest favorable long-term outcomes of clone-targeted chemotherapy in immunotactoid glomerulopathy

Immunotactoid glomerulopathy is a rare disease defined by glomerular microtubular immunoglobulin deposits. Since management and long-term outcomes remain poorly described, we retrospectively analyzed results of 27 adults from 21 departments of nephrology in France accrued over 19 years. Inclusion criteria were presence of glomerular Congo red-negative monotypic immunoglobulin deposits with ultrastructural microtubular organization, without evidence for cryoglobulinemic glomerulonephritis. Baseline manifestations of this cohort included: proteinuria (median 6.0 g/day), nephrotic syndrome (70%), microscopic hematuria (74%) and hypertension (56%) with a median serum creatinine of 1.5 mg/dL. Nineteen patients had detectable serum and/or urine monoclonal gammopathy. A bone marrow and/or peripheral blood clonal disorder was identified in 18 cases (16 lymphocytic and 2 plasmacytic disorders). Hematologic diagnosis was chronic/small lymphocytic lymphoma in 13, and monoclonal gammopathy of renal significance in 14 cases. Kidney biopsy showed atypical membranous in 16 or membranoproliferative glomerulonephritis in 11 cases, with microtubular monotypic IgG deposits (kappa in 17 of 27 cases), most commonly IgG1. Identical intracytoplasmic microtubules were observed in clonal lymphocytes from 5 of 10 tested patients. Among 21 patients who received alkylating agents, rituximab-based or bortezomib-based chemotherapy, 18 achieved a kidney response. After a median follow-up of 40 months, 16 patients had sustained kidney response, 7 had reached end-stage kidney disease, and 6 died. Chronic/small lymphocytic lymphoma appears as a common underlying condition in immunotactoid glomerulopathy, but clonal detection remains inconstant with routine techniques in patients with monoclonal gammopathy of renal significance. Thus, early diagnosis and hematological response after clone-targeted chemotherapy was associated with favorable outcomes. Hence, thorough pathologic and hematologic workup is key to the management of immunotactoid glomerulopathy.

Recurrence of DNAJB9-Positive Fibrillary Glomerulonephritis After Kidney Transplantation: A Case Series

RATIONALE & OBJECTIVE

Fibrillary glomerulonephritis (FGN) is a rare glomerular disease that often progresses to kidney failure requiring kidney replacement therapy. We have recently identified a novel biomarker of FGN, DnaJ homolog subfamily B member 9 (DNAJB9). In this study, we used sequential protocol allograft biopsies and DNAJB9 staining to help characterize a series of patients with native kidney FGN who underwent kidney transplantation.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

Between 1996 and 2016, kidney transplantation was performed on 19 patients with a reported diagnosis of FGN in their native/transplant kidneys. Using standard diagnostic criteria and DNAJB9 staining, we excluded 5 patients (4 atypical cases diagnosed as possible FGN and 1 donor-derived FGN). Protocol allograft biopsies had been performed at 4, 12, 24, 60, and 120 months posttransplantation. DNAJB9 immunohistochemistry was performed using an anti-DNAJB9 rabbit polyclonal antibody. Pre- and posttransplantation demographic and clinical characteristics were collected. Summary statistical analysis was performed, including nonparametric statistical tests.

OBSERVATIONS

The 14 patients with FGN had a median posttransplantation follow-up of 5.7 (IQR, 2.9-13.8) years. 3 (21%) patients had recurrence of FGN, detected on the 5- (n=1) and 10-year (n=2) allograft biopsies. Median time to recurrence was 10.2 (IQR, 5-10.5) years. Median levels of proteinuria and iothalamate clearance at the time of recurrence were 243mg/d and 56mL/min. The remaining 11 patients had no evidence of histologic recurrence on the last posttransplantation biopsy, although the median time of follow-up was significantly less at 4.4 (IQR, 2.9-14.4) years. 3 (21%) patients had a monoclonal protein detectable in serum obtained pretransplantation; none of these patients had recurrent FGN.

LIMITATIONS

Small study sample and shorter follow-up time in the nonrecurrent versus recurrent group.

CONCLUSIONS

In this series, FGN had an indolent course in the kidney allograft in that detectable histologic recurrence did not appear for at least 5 years posttransplantation.

New developments in the diagnosis of fibrillary glomerulonephritis

Fibrillary glomerulonephritis is a glomerular disease historically defined by glomerular deposition of Congo red-negative, randomly oriented straight fibrils that lack a hollow center and stain with antisera to immunoglobulins. It was initially considered to be an idiopathic disease, but recent studies highlighted association in some cases with autoimmune disease, malignant neoplasm, or hepatitis C viral infection. Prognosis is poor with nearly half of patients progressing to end-stage renal disease within 4 years. There is currently no effective therapy, aside from kidney transplantation, which is associated with disease recurrence in a third of cases. The diagnosis has been hampered by the lack of biomarkers for the disease and the necessity of electron microscopy for diagnosis, which is not widely available. Recently, through the use of laser microdissection-assisted liquid chromatography-tandem mass spectrometry, a novel biomarker of fibrillary glomerulonephritis, DnaJ homolog subfamily B member 9, has been identified. Immunohistochemical studies confirmed the high sensitivity and specificity of DnaJ homolog subfamily B member 9 for this disease; dual immunofluorescence showed its colocalization with IgG in glomeruli; and immunoelectron microscopy revealed its localization to individual fibrils of fibrillary glomerulonephritis. The identification of this tissue biomarker has already entered clinical practice and undoubtingly will improve the diagnosis of this rare disease, particularly in developing countries where electron microscopy is less available. Future research is needed to determine whether DnaJ homolog subfamily B member 9 is an autoantigen or just an associated protein in fibrillary glomerulonephritis, whether it can serve as a noninvasive biomarker, and whether therapies that target this protein are effective in improving prognosis.

Rare diagnosis in a patient with diabetes with nephrotic proteinuria

We report a 63-year-old man with well-controlled type 2 diabetes mellitus and hypertension, who presented with new onset nephrotic proteinuria and rapid deterioration in renal function. The atypical clinical presentation prompted us to consider a non-diabetic and non-hypertensive cause and to perform a renal biopsy. A diagnosis of fibrillarglomerulonephritis (FGn) was made based on electronic microscopy. Proteinuria remained in nephrotic range despite treatment with prednisolone, and renal function deteriorated. We suggest that other causes of proteinuria should be considered in patients with diabetes who present with the nephrotic syndrome when there is no other evidence of microvascular disease. We review the spectrum of fibrillar glomerulopathies including FGn, primary and secondary amyloidosis and immunotactoid glomerulonephritis.

Recurrent glomerular disease after kidney transplantation

PURPOSE OF REVIEW

With improving short-term kidney transplant outcomes, recurrent glomerular disease is being increasingly recognized as an important cause of chronic allograft failure. Further understanding of the risks and pathogenesis of recurrent glomerular disease enable informed transplant decisions, along with the development of preventive and treatment strategies.

RECENT FINDINGS

Multiple observational studies have highlighted differences in rates and outcomes for various recurrent glomerular diseases, although these rates have not markedly improved over the last decade. Emerging evidence supports use of rituximab to treat recurrent primary membranous nephropathy and possibly focal segmental glomerulosclerosis (FSGS), whereas eculizumab is effective in glomerular diseases associated with complement dysregulation [C3 glomerulopathy (C3G) and atypical hemolytic uremic syndrome (aHUS)].

SUMMARY

Despite the potential for recurrence in the allograft, transplant remains the optimal therapy for patients with advanced chronic kidney disease (CKD) secondary to primary glomerular disease. Biomarkers and therapeutic options necessitate accurate pretransplant diagnoses with opportunities for improved surveillance and treatment of recurrent glomerular disease posttransplant.

Histologic regression of fibrillary glomerulonephritis: the first report of biopsy-proven spontaneous resolution of disease

Fibrillary glomerulonephritis (FGN) is a rare immune complex type glomerulonephritis characterized by glomerular deposition of randomly oriented fibrils measuring 10–30 nm in thickness, and typically presents with proteinuria with or without renal insufficiency and hematuria. We present a case in which a patient initially presented at age 41 years with nephrotic-range proteinuria and hypertension; a kidney biopsy showed FGN. The patient was treated with angiotensin receptor blockage only, without immunosuppression as per patient preference, and the level of protein in the urine improved. During the follow-up period of 17 years, the patient developed type 2 diabetes mellitus. The patient re-presented with nephrotic-range proteinuria 17 years later, at the age of 58 years. A kidney biopsy was performed and showed diffuse diabetic glomerulosclerosis with secondary focal segmental glomerulosclerosis and related vascular changes. There was no evidence of FGN by immunofluorescence or electron microscopy. Although FGN has been rarely reported to regress clinically, this is the first documented case of histologic regression of FGN. The potential for FGN fibrils to regress spontaneously is important in the management of FGN patients considering that currently available immunosuppressive agents have limited efficacy, and is an encouraging finding for future studies aiming to find a cure for the disease.

Paraprotein-Related Kidney Disease: Glomerular Diseases Associated with Paraproteinemias

Paraproteins are monoclonal Igs that accumulate in blood as a result of abnormal excess production. These circulating proteins cause a diversity of kidney disorders that are increasingly being comanaged by nephrologists. In this review, we discuss paraprotein-related diseases that affect the glomerulus. We provide a broad overview of diseases characterized by nonorganized deposits, such as monoclonal Ig deposition disease (MIDD), proliferative GN with monoclonal Ig deposits (PGNMID), and C3 glomerulopathy, as well as those characterized by organized deposits, such as amyloidosis, immunotactoid glomerulopathy, fibrillary GN, and cryoglobulinemic GN, and rarer disorders, such as monoclonal crystalline glomerulopathies, paraprotein-related thrombotic microangiopathies, and membranous-like glomerulopathy with masked IgGκ deposits. This review will provide the nephrologist with an up to date understanding of these entities and highlight the areas of deficit in evidence and future lines of research.

A case report of unusually long lag time between immunotactoid glomerulopathy (itg) diagnosis and diffuse large B-cell lymphoma (DLBCL) development

Background

Immunotactoid glomerulopathy (ITG) is a rare cause of proteinuria characterized by organized microtubular deposits in the glomerulus. ITG has been associated with underlying lymphoproliferative disorders and any renal impairment may be reversible with treatment of the concomitant hematologic malignancy. This case is the first reported in literature where diffuse large B cell lymphoma developed two years following the initial ITG diagnosis.

Case presentation

A 55-year-old woman with a history of well-controlled diabetes mellitus and thalassemia trait presented with proteinuria (830 mg/day) in 2010. Initially, she was managed with renin-angiotensin-aldosterone-system blockade. In 2012, the proteinuria worsened (4.3 g/day) and a renal biopsy showed immunotactoid glomerulopathy (Fig. 1). Despite extensive work up, no lymphoproliferative disorder was initially found. In January 2014, the patient presented with a soft-palate mass found on biopsy to be diffuse large B-cell lymphoma. She received 6 cycles of R-CHOP, 4 cycles of high dose methotrexate chemotherapy for CNS prophylaxis and 30 Gy of Intensity Modulated Radiation Therapy. Follow-up revealed complete remission of diffuse large B-cell lymphoma and resolution of proteinuria from the ITG.

Conclusion

As we recognize that patients with ITG may develop hematopoietic neoplasms, close long-term monitoring is important. Moreover, treatment of the lymphoproliferative disorder can allow for complete remission of ITG.

[Glomerulopathies with organized monoclonal immunoglobulin deposits]

The spectrum of glomerular disorders with organized immunoglobulin (Ig) deposits is heterogeneous. It encompasses 2 mains categories: glomerulopathies with fibrillary deposits are mostly represented by immunoglobulinic amyloidosis (most commonly AL amyloidosis, characterized by monoclonal light chain deposits often of the lambda isotype), and pseudo-amyloid fibrillary glomerulonephritis in which deposits predominantly contain polyclonal IgG4. Glomerulopathies with microtubular deposits include cryoglobulinemic glomerulonephritis (type I and type II, with or without detectable serum cryoglobulin) and glomerulonephritis with organized microtubular monoclonal Ig deposits (GOMMID) also referred to as immunotactoid glomerulopathy. Pathological diagnosis requires meticulous studies by light microscopy (with systematic Congo red staining), immunofluorescence with specific conjugates, and electron microscopy. Ultrastructural studies are required to differentiate amyloid fibrils (8 to 10 nm in external diameter), pseudo-amyloid fibrils (15-20 nm) and microtubules (10 to 50 nm in external diameter, with a central hollow core). Glomerular deposits in type I cryoglobulinemic glomerulonephritis are arranged into parallel straight microtubules similar to those observed in GOMMID, but with different topography that allows distinction between the two entities. Glomerular substructures composed of circulating Igs should be distinguished from collagen fibrils that are commonly observed in glomerular disorders with or without deposition of monoclonal or polyclonal Igs.

Rapidly progressive glomerulonephritis due to coexistent anti-glomerular basement membrane disease and fibrillary glomerulonephritis

Anti-glomerular basement membrane (anti-GBM) disease is a major cause of rapidly progressive glomerulonephritis (RPGN). On the other hand, fibrillary glomerulonephritis (GN) typically presents as proteinuria, hematuria and renal insufficiency, but rarely as RPGN. Without electron microscopy, the diagnosis of fibrillary GN can be missed. We report a 68-year-old white woman who presented with RPGN with kidney biopsy demonstrating diffuse crescentic GN on light microscopy. By immunofluorescence, there was bright linear staining of the GBMs and smudgy mesangial staining for immunoglobulin G, C3, and kappa and lambda light chain. Electron microscopy revealed fibrillary deposits in the GBM and mesangium. A serum test for anti-GBM antibody was positive. To our knowledge, this is the first report of coexistence of fibrillary GN in a patient with anti-GBM disease. Electron microscopy is critical to identify the coexistence of other GN in patients presenting with crescentic GN.

A case of membranoproliferative glomerulonephritis associated with curved fibril deposition

Background

It is sometimes challenging to diagnose unsusual cases of fibrillary glomerulonephritis (FGN) and immunotactoid glomerulopathy (ITG), the rare causes of nephrotic syndrome.

Case presentation

A 75-year-old Japanese woman presented with nephrotic syndrome, microhematuria and renal insufficiency. Renal biopsy revealed membranoproliferative glomerulonephritis (MPGN) with IgM and weak C3 deposition. Congo red stain was negative. Electron microscopy demonstrated massive fibrils in the subendothelium, mesangium and subepithelium. The fibrils were partially parallel, partially curved and 17 nm in diameter. Cryoglobulin, hepatitis B virus (HBV) antigen, hepatitis C virus (HCV) antibody or antinuclear antibody were negative.

Conclusion

We report a case of MPGN associated with peculiar non-amyloid fibril deposition corresponding to neither FGN nor ITG.

De Novo Fibrillary Glomerulonephritis (FGN) in a Renal Transplant with Chronic Hepatitis C

Chronic hepatitis C viremia (HepC) has been associated with numerous renal manifestations both in native kidneys and in the setting of renal transplantation. Glomerulonephritis (GN) of the renal allograft in the setting of HepC most commonly manifests as type 1 membranoproliferative GN (MPGN), either representing recurrence of the original disease or arising de novo. Other GNs were reported after transplantation in the patient with HepC including membranous nephropathy and thrombotic microangiopathy, as well as an enhanced susceptibility to transplant glomerulopathy. We describe the first case of de novo fibrillary GN in a renal transplant patient with HepC where the primary renal disease was biopsy proven type 1 MPGN. We discuss this relationship in detail.

Long-term kidney disease outcomes in fibrillary glomerulonephritis: a case series of 27 patients

BACKGROUND

Fibrillary glomerulonephritis (GN) is a rare disorder with poor renal prognosis. Therapeutic strategies, particularly the use of immunosuppressive drugs, are debated.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

27 adults with fibrillary GN referred to 15 nephrology departments in France between 1990 and 2011 were included. All patients were given renin-angiotensin system blockers and 13 received immunosuppressive therapy, including rituximab (7 patients) and cyclophosphamide (3 patients).

OUTCOMES & MEASUREMENTS

Clinical and histologic features of patients and kidney disease outcome. Renal response was defined as a >50% decrease in 24-hour proteinuria with <15% decline in estimated glomerular filtration rate (eGFR).

RESULTS

All patients presented with proteinuria, associated with nephrotic syndrome (41%), hematuria (73%), and hypertension (70%). Baseline median eGFR was 49 mL/min/1.73 m(2). Eight patients had a history of autoimmune disease and none had evidence of hematologic malignancy during follow-up. Light microscopic studies showed mesangial GN (70%), predominant pattern of membranous GN (19%), or membranoproliferative GN (11%). By immunofluorescence, immunoglobulin G (IgG) deposits (IgG4, 15/15; IgG1, 9/15) were polyclonal in 25 cases. Serum IgG subclass distribution was normal in the 6 patients tested. After a median 46-month follow-up, renal response occurred in 6 of 13 patients who received immunosuppressive therapy with rituximab (5 patients) or cyclophosphamide (1 patient). Of these, 5 had a mesangial or membranous light microscopic pattern, and median eGFR before therapy was 76 mL/min/1.73 m(2). In contrast, chronic kidney disease progressed in 12 of 14 patients who were not given immunosuppressive therapy, 10 of whom reached end-stage renal disease.

LIMITATIONS

Number of patients, retrospective study, use of multiple immunosuppressive regimens.

CONCLUSIONS

The therapeutic approach in fibrillary GN remains challenging. The place of immunosuppressive therapy, particularly anti-B-cell agents, needs to be assessed in larger collaborative studies.

Recurrence of fibrillary glomerulonephritis in a renal transplant recipient

Fibrillary glomerulonephritis (FGN) is a rare glomerular deposition disease and a rare cause of nephrotic syndrome. The patients usually present with renal insufficiency, nephrotic range proteinuria and microscopic hematuria. The electron microscopy study is the only means of diagnosis. The clinical course of the disease is generally unpredictive and the patients inevitably progress to ESRD. Here, we describe a case of FGN, which presented with nephrotic syndrome and impaired renal function. Renal biopsy showed that 26 out of 30 glomeruli were completely sclerosed. Remaining showed mesangial expansion and double contour consistent with a membranoproliferative pattern, with 70 % interstitial fibrosis and tubular atrophy. Immunofluorescence revealed C3 (2+) diffuse mesangial deposits. Electron microscopic showed subendothelial dense deposits with organized tubular structures. During follow-up, the patient underwent renal transplantation from a living unrelated kidney donor. Later on, as the renal allograft function showed deterioration, renal biopsy was performed and showed recurrence of FGN in the renal allograft.

Plasmapheresis leading to remission of refractory nephrotic syndrome due to fibrillary glomerulonephritis: a case report

INTRODUCTION

Fibrillary glomerulonephritis (FibGN) is characterized by extracellular deposition of Congo red-negative microfibrils within the glomerular mesangium and leads to gross proteinuria or nephrotic syndrome. After diagnosis of FibGN, end-stage renal disease occurs within four years in 50% of patients.

CASE PRESENTATION

A 36-year-old Caucasian woman with proteinuria and intermittent nephrotic syndrome due to FibGN intermittently received immunosuppressive therapies, including glucocorticoids, mycophenolate mofetil, and rituximab, for 10 years. However, disease remission was not achieved and progressive kidney injury developed. Ultimately, in stage IV of chronic kidney disease (Kidney Disease: Improving Global Outcomes), three cycles of plasmapheresis of five to seven sessions each were performed every three to four months, reducing steady-state proteinuria from 7 to less than 1 g/day. Here, plasmapheresis led to a remission of nephrotic syndrome associated with FibGN.

CONCLUSIONS

Plasmapheresis therapy is proposed as a further option for immunosuppressant-refractory FibGN.

Fibrillary glomerulonephritis associated with Behçet's syndrome

Fibrillary glomerulonephritis (FGN) is a rare cause of progressive renal dysfunction resulting in fibrillary deposits in the mesangium and/or glomerular basement membrane (GBM). Some case reports have shown FGN in patients with rheumatoid arthritis and other autoimmune diseases. This is the first case report of FGN in a patient with Behçet's syndrome. The most common renal histological finding in Behçet's syndrome is secondary amyloidosis. A 46-year-old woman with a 4-year history of Behçet's syndrome was referred to the nephrology clinic with foamy urine with non-selective proteinuria (urine protein-to-creatinine ratio was 1400 mg protein/g creatinine) and microscopic hematuria. Serum and urine protein electrophoresis showed no evidence of monoclonal gammopathy. A renal biopsy was performed. Light microscopy showed mesangial widening and nodular expansion with hyaline deposits. Immunofluorescence microscopy revealed immunoglobulin M deposits in the mesangium. Congo red staining was negative. Electron microscopy showed fibrillary deposits on the GBM. Pathological findings were consistent with FGN. She had been taking 50 mg azathioprine and 3000 mg mesalazine per day for 4 years due to Behçet's syndrome, so we did not add any other immunosuppressive agents or corticosteroids. Treatment of this glomerulopathy is not promising. It has been noted that none of the various approaches, including corticosteroid, plasmapheresis, and cytotoxic therapy, improves prognosis.

Therapeutic apheresis for renal disorders

This review summarizes the clinical evidence and practical details for the use of plasmapheresis and other apheresis modalities for each indication in nephrology. Updated information on the molecular biology and immunology of each renal disease is discussed in relation to the rationale for apheresis therapy and its place amid other available treatments. Autoantibody-mediated diseases, such as anti-GBM (anti-glomerular basement membrane) glomerulonephritis (GN), ANCA (antineutrophil cytoplasmic antibody)-related GN and the antibody-mediated type of TTP (thrombotic thrombocytopenic purpura), and alloantibody-mediated diseases such as kidney transplant sensitization and humoral rejection, can be treated by various plasmapheresis methods. These include standard plasmapheresis with a replacement volume, or plasmapheresis with online plasma purification using adsorption columns or secondary filtration. However, it should be noted that the pathogenic molecules implicated in FSGS (focal segmental glomerulosclerosis), myeloma cast nephropathy, and perhaps other diseases are too small to be removed by most online purification methods. A great majority of controlled trials and series on which evidence-based treatment recommendations are made were performed using centrifugal plasmapheresis; it is presumed that membrane-separation plasmapheresis is equally efficacious. For some rarer diseases, such as MPGN (membranoproliferative GN) type 2 with factor H abnormalities or C3Nef (C3 nephritic factor) autoantibodies, there are only a few case reports, but enough scientific understanding to warrant a trial of plasmapheresis in severe cases. Photopheresis, which is effective for cell-mediated rejection in heart and lung transplantation, has not yet found a place in the routine treatment of kidney transplant rejection.

Fibrillary glomerulonephritis in a patient with systemic lupus erythematosus: a rare association

We report the case of a 28-year-old man with systemic lupus erythematosus (SLE) and rapidly progressive glomerulonephritis (RPGN) due to fibrillary glomerulonephritis (FGN). The patient had a history of SLE and had been treated with mycophenolate mofetil, prednisone, and intravenous cyclophosphamide for his renal and extra-renal manifestations. In spite of this treatment, he developed RPGN. A subsequent renal biopsy revealed diffuse proliferative glomerulonephritis with fibrillary deposits. SLE is rarely associated with FGN, however FGN should be considered in the differential diagnosis of any SLE patient with RPGN.

[Fibrillary nonamyloid glomerulonephritis: a rare etiology of nephrotic syndrome]

The fibrillary nonamyloïd glomerulonephritis is a glomerulopathy with fibrillar, nonamyloid deposits of predominantly polyclonal immunoglobulin G. It is an idiopathic glomerulopathy responsible for heavy proteinuria, generally in the nephrotic range, and renal failure up to end stage in 40 % of the cases after five years. The histologic pattern is variable, correlating with renal prognosis. The Congo red-negativity of the deposits and the size of the fibrils on electron microscopy make the differential diagnosis with amyloid deposits. There is no specific efficient therapy. Recurrence in the transplant is frequent, but with better renal prognosis.

Fibrillary glomerulonephritis: a report of 66 cases from a single institution

BACKGROUND AND OBJECTIVES

Fibrillary glomerulonephritis (FGN) is a rare primary glomerular disease. Most previously reported cases were idiopathic. To better define the clinical-pathologic spectrum and prognosis, we report the largest single-center series with the longest follow-up.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The characteristics of 66 FGN patients who were seen at Mayo Clinic, Rochester, between 1993 and 2010 are provided.

RESULTS

The mean age at diagnosis was 53 years. Ninety-five percent of patients were white, and the female:male ratio was 1.2:1. Underlying malignancy (most commonly carcinoma), dysproteinemia, or autoimmune disease (most commonly Crohn's disease, SLE, Graves' disease, and idiopathic thrombocytopenic purpura), were present in 23, 17, and 15% of patients, respectively. Presentation included proteinuria (100%), nephrotic syndrome (38%), renal insufficiency (66%), hematuria (52%), and hypertension (71%). The most common histologic pattern was mesangial proliferative/sclerosing GN followed by membranoproliferative GN. During an average of 52.3 months of follow-up for 61 patients with available data, 13% had complete or partial remission, 43% had persistent renal dysfunction, and 44% progressed to ESRD. The disease recurred in 36% of 14 patients who received a kidney transplant. Independent predictors of ESRD by multivariate analysis were older age, higher creatinine and proteinuria at biopsy, and higher percentage of global glomerulosclerosis.

CONCLUSIONS

Underlying malignancy, dysproteinemia, or autoimmune diseases are not uncommon in patients with FGN. Prognosis is poor, although remission may occur in a minority of patients without immunosuppressive therapy. Age, degree of renal impairment at diagnosis, and degree of glomerular scarring are predictors of renal survival.

Recurrent glomerular disease after kidney transplantation

PURPOSE OF REVIEW

Recurrent glomerulonephritis is the third most common cause of graft failure, ranking only behind immunologic rejection and death with a functioning graft. Knowledge of the rates and timing of recurrent glomerular disease are important in counseling potential transplant recipients and preventive and therapeutic treatment strategies are necessary for those patients at risk.

RECENT FINDINGS

Large observational studies that have analyzed posttransplant biopsies have confirmed the high rates of glomerular disease recurrence in renal allografts. Newer immunosuppressive protocols over the past 10 years have not affected the rate of disease recurrence or graft loss. There is emerging evidence that rituximab may be efficacious in treating recurrent membranous nephropathy and focal segmental glomerulosclerosis; however, larger clinical trials are warranted.

SUMMARY

Recurrent glomerulonephritis is an important determinant of long-term outcomes after transplantation, requiring appropriate counseling to potential transplant recipients. Currently, there are no proven strategies to prevent recurrent glomerulonephritis in renal transplant recipients. Despite the high rates of recurrent disease, long-term graft survival is still very good and transplantation remains the best treatment option for patients with end-stage renal disease from primary glomerulonephritis.

The spectrum of kidney involvement in lymphoma: a case report and review of the literature

Kidney involvement is an under-recognized complication of both Hodgkin and non-Hodgkin lymphoma. The diversity of lymphoma-related renal manifestations makes diagnosis difficult. Although abrupt worsening of kidney function may be the first sign of malignant disease, renal effects can be subtle or even silent. The causes of renal involvement similarly are varied. We discuss a case of non-Hodgkin lymphoma and associated kidney failure from several distinct malignancy-related mechanisms and review the spectrum of lymphoma-related kidney involvement.

A case of recurrent immunotactoid glomerulopathy in an allograft treated with rituximab

Immunotactoid glomerulopathy is a glomerular disorder typified by hollow cylindrical and sometimes spherical microtubular deposits, with a diameter of 30-40 nm, but up to 90 nm, often in a parallel arrangement or in intersecting bundles. These patients frequently end up receiving kidney transplants due to progressive renal insufficiency. Known to recur in renal transplant recipients with variable outcomes, its treatment options are limited. Classically steroids, cyclophosphamide, mycophenolate mofetil, and plasma exchanges have been used to treat these recurrences. More recently, rituximab has been suggested as a treatment and has demonstrated improved outcomes in other glomerular diseases. Herein we describe a case of a middle-aged female renal transplant recipient for end-stage renal disease secondary to immunotactoid glomerulopathy, who experienced a recurrence of this condition in the transplanted kidney. Following a failure of conventional therapy we administered a course of rituximab, resulting in a reduction and stabilization of her serum creatinine level while her proteinuria persisted.

Fibrillary glomerulonephritis and renal failure in a child with systemic lupus erythematosus

Fibrillary glomerulonephritis (FGN) is a rare immune-mediated glomerulopathy characterized by randomly arranged immunoglobulin (Ig) deposits on electron microscopy. Only seven pediatric cases have been reported, and the incidence in adults is about 1.5%. A 12-year-old boy presented with systemic lupus erythematosus (SLE) with World Health Organization Class IV lupus nephritis. A repeat biopsy carried out due to a poor response to standard immunosuppressive therapy and worsening renal functions revealed diffuse proliferative glomerulonephritis with fibrillary deposits. Despite aggressive immunosuppression with plasmapheresis and rituximab, the patient developed end stage renal disease. This is an atypical pediatric case characterized by SLE-associated FGN and a poor prognosis.

Long-term outcome of kidney transplantation in patients with fibrillary glomerulonephritis or monoclonal gammopathy with fibrillary deposits

To determine the outcome of kidney transplantation in patients with fibrillary glomerulonephritis (FGN), a rare glomerular disease, we followed 12 patients, 5 with FGN and 7 patients with monoclonal gammopathy and fibrillary deposits (MGFD), who underwent 15 kidney transplants since 1988 with a median follow-up of 52 months. Recurrent disease did not arise in any of the patients with FGN but developed in 5 patients with MGFD. Seven allografts failed: 1 in the FGN group and 6 in the MGFD group. Median allograft survival for patients with MGFD was 37 months but had not been reached in FGN patients. One patient with FGN had primary allograft failure secondary to graft thromboembolism. Three patients with MGFD were re-transplanted and one lost the second allograft to recurrent disease, but the other two died from hematological malignancy. Another patient was diagnosed with MPGN type III and did not have detectable fibrillary material 22 months after transplantation. One patient with MGFD had stable allograft function 6 months post-transplant but another, with recurrent disease, underwent peripheral blood stem cell transplantation and regained stable allograft function. Our study shows that kidney transplantation appears safe in patients with FGN with little risk of recurrence. However, patients with MGFD have a significant risk for disease recurrence. Whether the development of hematological malignancies following transplantation in this group is related to their original disease or was coincidental requires further studies.

A case of fibrillary glomerulonephritis with unusual IgM deposits and hypocomplementemia

Fibrillary glomerulonephritis (FGN) is rare immune-mediated GN with predominant immunoglobulin (Ig) G deposits, normal serum complement levels, and poor prognosis. The incidence of FGN is less than 1% in the adult population, and only six pediatric cases have been reported in the English literature. A 12-year-old girl presented with acute nephrotic-nephritic syndrome mimicking atypical clinical features of acute poststreptococcal GN (APSGN). Clinical features had completely resolved in 2 weeks, but the serum complement levels remained low. Renal biopsy was done 6 months later, and she was diagnosed as having FGN with unusual IgM deposits. Despite persistently low serum complement levels during the subsequent 3 years, clinical relapse did not develop. This case was an atypical form of FGN characterized by unusual IgM deposits, persistent hypocomplementemia, and good prognosis, which suggests that childhood FGN is not necessarily a disease with poor prognosis.

Fibrillary glomerulonephritis and immunotactoid glomerulopathy

Fibrillary glomerulonephritis is a now widely recognized diagnostic entity, occurring in approximately 1% of native kidney biopsies in several large biopsy series obtained from Western countries. The distinctive features are infiltration of glomerular structures by randomly arranged fibrils similar in appearance but larger than amyloid fibrils and the lack of staining with histochemical dyes typically reactive with amyloid. It is widely but not universally recognized to be distinct from immunotactoid glomerulopathy, an entity characterized by glomerular deposits of immunoglobulin with substructural organization as microtubules and with clinical associations with lymphoplasmacytic disorders. The pathophysiologic basis for organization of the glomerular deposits as fibrils or microtubules in these entities remains obscure.

Pathology of glomerular deposition diseases

In routine diagnosis on renal biopsy, one of the confusing fields for pathological diagnoses is the glomerulopathies with fibrillary structure. The primary glomerulopathies with a deposit of ultrastructural fibrillary structure, which are negative for Congo-red stain but positive for immunoglobulins, include fibrillary glomerulonephritis and immunotactoid glomerulopathy. Several paraproteinemias including cryoglobulinemia, monoclonal gammopathy, and light chain deposition disease as well as hematopoietic disorders including plasmacytoma, plasma cell dyscrasia, and B cell lymphoproliferative disorders involve glomerulopathy with an ultrastructural fibrillary structure. A rare glomerulopathy with fibrillary structure that stains negative for Congo-red as well as for immunoglobulins has been also reported. The pathological diagnoses of these glomerulopathies can include either glomerular diseases, or paraproteinemic diseases, or hematopoietic diseases. The terminology is still confusing when glomerular diseases can be combined with paraproteinemic diseases and/or hematopoietic diseases. Therefore, the generic term, 'glomerular deposition disease' (GDD), has been proposed by pathologists with a requirement for clinicians to detect autoantibodies, paraproteins as well as to carry out a bone marrow check. An attempt has been made to rearrange the diseases with related disorders of fibrillary deposits, based on detailed clinical and pathological finding and to elucidate the correlation between GDD, paraproteinemia, and hematopoietic disorder.

Fibrillary glomerulonephritis with small fibrils in a patient with the antiphospholipid antibody syndrome successfully treated with immunosuppressive therapy

BACKGROUND

Fibrillary glomerulonephritis is a rare cause of progressive renal dysfunction, often leading to the need for dialysis within a few years. The role of immunosuppressive treatment is still uncertain although this has been tried with variable success.

CASE PRESENTATION

A 56 year old woman with the antiphospholipid antibody syndrome (IgM anticardiolipin antibodies) was seen in the nephrology clinic with haematuria, proteinuria, and worsening renal function. A renal biopsy demonstrated a mesangial proliferative glomerulonephritis on light microscopy and smaller fibrils (10.6-13.8 nm in diameter) than is usual for fibrillary glomerulonephritis (typically 18-22 nm) on electron microscopy. Amyloidosis was excluded following detailed evaluation. On account of rapidly worsening renal failure she was started on cyclophosphamide and prednisolone which led to the partial recovery and stabilization of her renal function.

CONCLUSION

This case highlights the need for routine electron microscopy in native renal biopsies, where the differential diagnosis is wide and varied and the light and immunofluorescence microscopic findings may be non specific.

Fibrillary Glomerulonephritis Presenting as Rapidly Progressive Renal Failure in a Young Female: A Case Report

Fibrillary Glomerulonephritis (FGN) is a rare clinical entity presenting in majority of patients with nephrotic range proteinuria, microscopic hematuria, impaired renal function and hypertension. The mean age of presentation is reported to be beyond 50 years with 50 patients developing end stage renal disease within a few years. A 28-year-old female presented to us with non-nephrotic range proteinuria, rapidly progressive renal failure (RPRF), microscopic hematuria and mild hypertension. The patient had undergone a renal biopsy at a peripheral center, which was reported as membranoproliferative glomerulonephritis (MPGN) and was being treated with steroids without any benefit. The patient on re-biopsy at our center was diagnosed as FGN on electron microscopy (EM). The patient responded to intravenous pulse methylprednislone and oral cyclophosphamide and is off dialysis for 10 months now. This case highlights the varied clinical and histological presentations of FGN which makes the disease difficult to diagnose more so, in a country like ours where EM is available in only a few centers. An accurate diagnosis aided by high index of clinical suspicion and EM can help in the initiation of appropriate therapy, thereby improving the outcome in this disease which otherwise has a poor prognosis.

Immunotactoid keratopathy: a clinicopathologic case report and a review of reports of corneal involvement in systemic paraproteinemias

Corneal deposits in association with paraproteinemias have been well described in the ophthalmic literature. Recent reports in the renal literature have described immunotactoid deposition associated with glomerulopathy-organized microtubular deposits of IgGkappa that measured 32-50 nm in diameter on renal biopsies. We present a case of corneal immunotactoid deposition in the setting of chronic lymphocytic leukemia and review previous reports of corneal deposition in the setting of systemic paraproteinemia, highlighting the etiology, differential diagnosis, prognosis, and treatment of corneal involvement. We propose the use of the term immunotactoid keratopathy to describe corneal IgGkappa deposits appearing as tubular, electron-dense, crystalloid deposits with a central lucent core on electron microscopy and suggest that these patients undergo directed systemic workup to evaluate for potential etiologies of their systemic paraproteinemia. To illustrate the spectrum of paraprotein deposition in the cornea, and to emphasize the importance of ophthalmic evaluation in the setting of systemic paraproteinemias, we include a case of a 44-year-old man with immunoprotein corneal deposition who was subsequently diagnosed with multiple myeloma.