Myeloperoxidase-antineutrophil cytoplasmic antibody-associated glomerulonephritis with membranous nephropathy in remission

Myeloperoxidase-Associated Membranous Nephropathy in Antineutrophil Cytoplasmic Antibody-Associated Glomerulonephritis

Introduction

Antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (GN) is characterized by pauci-immune crescentic GN. Myeloperoxidase ANCA-associated GN (MPO-ANCA GN) with membranous nephropathy (MN), where bright granular capillary MPO and IgG staining along the glomerular basement membrane (GBM) is present, has been reported; however, its clinicopathological features remain unclear.

Methods

We investigated 7 MPO-ANCA GN with MN and 11 control cases (6 MPO-ANCA GN and 5 primary MN cases). Proteomics of laser microdissected glomeruli followed by immunohistochemical analysis was performed to identify causal antigens in MPO-ANCA GN with MN. We described the clinicopathological features of MPO-associated MN compared with those of MPO-ANCA GN and primary MN.

Results

We detected proteomic MPO and granular capillary MPO deposits in all MPO-ANCA GN with MN cases. Confocal microscopy revealed MPO and IgG colocalization along the GBM. MPO-associated MN clinicopathological features include greater proteinuria, a higher fibrous crescent rate, and a lower MPO-ANCA titer than MPO-ANCA GN. The estimated glomerular filtration rate (eGFR) and urinary protein excretion were lower in MPO-associated MN than in primary MN.

Conclusion

MPO-associated MN, a unique type of secondary MN where MPO serves as the causal antigen, is a subset of MPO-ANCA GN with MN. Prolonged periods of MPO-ANCA GN and a low MPO-ANCA titer might be related to MPO-associated MN development.

Clinical and Immunologic Characteristics of Patients With ANCA-Associated Glomerulonephritis Combined With Membranous Nephropathy: A Retrospective Cohort Study in a Single Chinese Center

The concurrent antineutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN) and membranous nephropathy (MN) have been increasingly documented, mainly in case studies and case series; however, the differences of clinical and pathologic characteristics as well as outcomes between ANCA-GN patients with and without MN remain unclear. The current study investigated the clinical and immunologic features of patients with combined ANCA-GN and MN in a large cohort. Twenty-seven of 223 patients had combined ANCA-GN and MN; they had significantly higher levels of initial serum creatinine, higher Birmingham Vasculitis Activity Score and poorer renal outcome than ANCA-GN patients without MN (P < 0.05). ANCA-GN patients with MN could recognize the light chain of myeloperoxidase more frequently than those without MN (P < 0.05). The prevalence of circulating anti-PLA2R antibodies and glomerular PLA2R deposits was significantly lower in patients with combined ANCA-GN and MN than that in patients with idiopathic MN (P < 0.05). Compared with the idiopathic MN patients, the patients with combined ANCA-GN and MN had significantly higher recognition frequency of immunoglobulin (Ig) G2 and IgG3, and significantly lower recognition frequency of IgG4 (P < 0.05). Patients with combined ANCA-GN and MN had distinct clinical features and a different pathogenesis of MN.

Membranous Nephropathy With MPO-ANCA-Associated Crescentic GN

Introduction:

Antineutrophil cytoplasmic antibodies (ANCA)-associated glomerulonephritis (GN) is characterized by necrotizing and crescentic GN with paucity of immunoglobulin (Ig) and complement deposition, which is also known as pauci-immune crescentic GN. Membranous nephropathy (MN) is characterized by the formation of subepithelial immune deposit with resultant changes in glomerular basement membrane (GBM), most notably spike formation.

Case Presentation:

A 48-year-old man presented with marked proteinuria, hypoalbuminemia, and renal dysfunction with positive results for myeloperoxidase (MPO) and ANCA. Renal biopsy revealed crescents and thick GBM with subepithelial spikes along with IgG deposition on immunofluorescent staining. The condition was diagnosed as MN with MPO-ANCA-associated crescentic GN. He was treated with intravenous methylprednisolone and cyclophosphamide. After one-month follow-up, antibody level and renal function did not improve.

Conclusions:

Coexistence of MN with MPO-ANCA crescentic GN is very rare and should be managed aggressively.

A case of membranous nephropathy and myeloperoxidase anti-neutrophil cytoplasmic antibody-associated glomerulonephritis

Membranous nephropathy (MN) may be a primary disease or secondary to autoimmune conditions such as systemic lupus erythematosus, infection (for example, with hepatitis B or C virus), cancer or drugs. In primary MN, crescents are rarely observed. Therefore, the presence of crescents suggests another underlying disease, for example lupus nephritis, anti-glomerular basement membrane disease or anti-neutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN). The coexistence of primary MN and ANCA-GN is rare. In the present case, a 51-year-old female with mild edema in the lower extremities for 1 year was admitted to hospital for renal biopsy. The serum test for myeloperoxidase (MPO)-ANCA was positive. The patient was diagnosed with stage 2 MN with crescentic glomerulonephritis type 3; however, no causal association was found between these two diseases in this case. Treatment was initiated with 500 mg methylprednisolone for 3 days followed by 40 mg of oral methylprednisolone together with 50 mg cyclophosphamide twice per day. One month following treatment, the biochemical data results of the patient had improved.

Membranous nephropathy superimposed on Churg-Strauss syndrome

The association of membranous nephropathy with Churg-Strauss syndrome is not widely reported. We present a patient with myeloperioxidase–perinuclear antineutrophilic cytoplasmic antibody (MPO-pANCA)-positive necrotizing and crescentic glomerulonephritis who later developed membranous nephropathy.

A case presenting with the possible relationship between myeloperoxidase-antineutrophil cytoplasmic antibody-associated glomerulonephritis and membranous changes of the glomerular basement membrane

A 72-year-old woman exhibited elevated serum myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) levels since 2006. Her serum creatinine (sCr) levels increased from 0.5 to 1.62 mg/dl in a stepwise pattern with proteinuria and hematuria up to January 2011. Renal biopsy indicated global sclerosis (14 %), fibrocellular crescents (28 %), and Swiss cheese-like appearance of the glomerular basement membrane (GBM) on light microscopy. IgG4 staining was negative. Immunofluorescent examination indicated granular staining with IgG and C3 along the GBM. MPO-ANCA-associated glomerulonephritis with membranous nephropathy (MN) was diagnosed. As chronic changes were relatively evident in the renal biopsy specimen without acute augmentation of renal function, immunosuppressive therapy was not administered. Thereafter, rapidly progressive renal dysfunction occurred (sCr, 3.67 mg/dl in May 2011) with proteinuria (~2 g/day), hematuria, and elevated serum MPO-ANCA levels. Therefore, a second renal biopsy was performed in May 2011, indicating global sclerosis (42 %) and cellular crescents (35 %) on light microscopy. Electron microscopy indicated electron-dense deposits in the GBM and mesangial lesions. Steroid therapy was subsequently initiated, and the patient's renal function partially improved. MPO-ANCA levels decreased to within normal limits and hematuria disappeared. MPO-ANCA-associated glomerulonephritis with MN is a rare dual glomerulopathy. However, complication should be considered when urinary protein appears in large amounts. Secondary MN was suspected due to the lack of IgG4 staining and distribution of electron-dense deposits to the mesangial lesion. Renal dysfunction occurring in a stepwise pattern may be attributed to intermittent augmentation in MPO-ANCA-associated glomerulonephritis.

A case of myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA)-associated glomerulonephritis and concurrent membranous nephropathy

Background

Myeloperoxidase anti-neutrophil cytoplasmic antibody-associated glomerulonephritis (MPO-ANCA-GN) and concurrent membranous nephropathy (MN) are very rare combination. Their causal relationship has been suggested, but not determined.

Case presentation

A 73-years-old male with 5-year history of proteinuria underwent an operation for his sigmoid colon cancer. Seven months later, he was referred to a nephrology division due to an exacerbating renal function and hypoalbuminemia. Laboratory examination revealed positive MPO-ANCA in the serum. A renal biopsy revealed a necrotizing extracapillary proliferative glomerulonephritis with crescents, demonstrating MPO-ANCA-GN. Whereas, immunofluorescent staining documented granular deposition of immumoglobulin (Ig) G and C3 along the capillary wall and electron microscopy showed subepithelial deposits in the glomerular basement membrane demonstrating MN. Immunofluorescent staining of IgG subclass showed positive IgG1, IgG2, negative IgG3 and weak positive IgG4 suggested the possibility of malignancy-associated MN.

Conclusion

Combination of MPO-ANCA-GN and MN are rare. Although the causal relationship has been suggested in some cases, we should consider all the possibilities including idiopathic MN and secondary MN associated with malignancy, drug use or infection.

Membranous glomerulopathy with superimposed pauci-immune necrotizing crescentic glomerulonephritis

We describe a 61-year-old woman with acute kidney injury, nephrotic range proteinuria and hematuria. Kidney biopsy showed membranous glomerulopathy (MG) with superimposed pauci-immune necrotizing crescentic glomerulonephritis (PNCGN). Coexistent MG and PNCGN is a rare occurrence. The diagnosis of such an exceptionally rare combination relies on the combination of renal biopsy findings and serologic testing. We also review previous reported cases and discuss possible pathogenesis of this rare dual glomerulopathy.

MPO-ANCA associated crescentic glomerulonephritis with numerous immune complexes: case report

Background

Antineutrophil cytoplasmic antibody (ANCA)-associated crescentic glomerulonephritis (CGN) is a major cause of rapidly progressive glomerulonephritis (RPGN). ANCA-associated CGN is generally classified into pauci-immune RPGN, in which there are few or no immune complexes.

Case Presentation

A 78-year-old man presented with RPGN after a 7-year course of chronic proteinuria and hematuria with stable renal function. A blood examination showed a high titer of myeloperoxidase (MPO)-ANCA. A renal biopsy showed crescentic glomerulonephritis with abundant subepithelial, intramenbranous and subendothelial deposits by electron microscopy, leading to the diagnosis of ANCA-associated CGN superimposed on type 3 membranoproliferative glomerulonephritis (MPGN).

Conclusions

This case is unique in that type 3 MPGN and MPO-ANCA-associated CGN coexisted, and no similar case has been reported to date. Because ANCA-associated CGN has a predilection for elderly individuals and primary type 3 MPGN is rarely seen in this age group, coincidental existence appears less likely. This case may confer valuable information regarding the link between immune complex and ANCA-associated CGN.

Etanercept-induced necrotizing crescentic glomerulonephritis in two patients with rheumatoid arthritis

We present two patients with rheumatoid arthritis (RA) who developed necrotizing crescentic glomerulonephritis (NCGN) during etanercept therapy. Both patients developed proteinuria and hematuria, and one progressed to renal failure. Renal biopsy revealed NCGN. In both patients, nephritis improved following discontinuation of etanercept and administration of prednisolone. Physicians should be aware of etanercept-induced GN in patients with RA on anti-tumor necrosis factor therapy.

MPO-ANCA crescentic glomerulonephritis complicated by membranous nephropathy: MPO demonstrated in epimembranous deposits

An elderly woman presented with haematuria and proteinuria accompanied by elevated serum myeloperoxidase (MPO)-specific anti-neutrophil cytoplasmic antibodies (MPO-ANCA). A renal biopsy revealed mild mesangial proliferation with fibrocellular crescent formation and a membranous glomerular lesion. Immunofluorescence microscopy using FITC-labelled rabbit anti-human MPO antibodies revealed granular MPO deposition along the glomerular capillary walls (GCW) with a staining profile similar to that of glomerular IgG deposition. The one-year follow-up renal biopsy revealed minimal IgG and undetectable MPO deposition. Both MPO and MPO-ANCA might have been responsible for the IgG immune depositions along the GCW in this patient.

Benzylthiouracil-induced glomerulonephritis

Vasculitis is a rare complication of antithyroid drugs (ATDs). It was first described with Propylthiouracil (PTU). We report a new case of antineutrophil cytoplasmic antibody (ANCA) vasculitis with glomerulonephritis induced by Benzylthiouracile (BTU). A 50-year-old man with Graves disease treated with BTU developed general malaise and haematuria without skin rash or respiratory involvement. Laboratory data revealed acute renal failure with proteinuria and haematuria. An indirect immunofluorescence test for ANCA was positive, showing a perinuclear pattern with specificity antimyeloperoxidase (MPO). A renal biopsy was performed and revealed pauci-immune extracapillary glomerular nephropathy and necrotic vasculitis lesions. Based on these findings we concluded to the diagnosis of rapidly progressive glomerulonephritis associated with ANCA induced by BTU therapy. The drug was therefore discontinued and the patient was treated with steroids and immunosuppressive treatment during 3 months. Renal failure, proteinuria and haematuria significantly improved within 2 months. However, P-ANCA remained positive until 10 months after drug withdrawal. Thyroid function was kept within normal range using iodine solution. We demonstrated clearly that BTU may induce severe forms of vasculitis with glomerulonephritis. Thus, the ANCA must be measured when confronted to systemic manifestation during treatment.

Membranous glomerulonephritis with ANCA-associated necrotizing and crescentic glomerulonephritis

BACKGROUND AND OBJECTIVES

Only rare cases of concurrent membranous glomerulonephritis (MGN) and antineutrophil cytoplasmic antibody (ANCA)-associated necrotizing and crescentic glomerulonephritis (NCGN) have been reported.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The authors report the clinical and pathologic findings in 14 patients with MGN and ANCA-associated NCGN.

RESULTS

The cohort consisted of eight men and six women with a mean age of 58.7 yr. ANCA positivity was documented by indirect immunofluorescence or ELISA in all patients. Indirect immunofluorescence was positive in 13 patients (seven P-ANCA, five C-ANCA, one atypical ANCA). ELISA was positive in nine of 10 patients (five MPO-ANCA, three PR3-ANCA, one MPO- and PR3-ANCA). Clinical presentation included heavy proteinuria (mean 24-hr urine protein 6.5 g/d), hematuria, and acute renal failure (mean creatinine 4.4 mg/dl). Pathologic evaluation revealed MGN and NCGN, with crescents involving a mean of 32% of glomeruli. On ultrastructural evaluation, the majority of cases showed stage I or II membranous changes. Follow-up was available for 13 patients, 12 of whom were treated with steroids and cyclophosphamide. At a mean follow-up of 24.3 mo, five patients progressed to ESRD, seven had stabilization or improvement in renal function, and one had worsening renal function. Five patients, including three with ESRD, died during the follow-up period. The only independent predictor of progression to ESRD was serum creatinine at biopsy.

CONCLUSIONS

MGN with ANCA-associated NCGN is a rare dual glomerulopathy seen in patients with heavy proteinuria, acute renal failure, and active urine sediment. Prognosis is variable, with 50% of patients reaching endpoints of ESRD or death.

Membranous glomerulopathy induced by myeloperoxidase-anti-neutrophil cytoplasmic antibody-related crescentic glomerulonephritis

A 68-year-old woman was referred for evaluation of nephrotic-range proteinuria and a course suggesting rapidly progressive glomerulonephritis. Serum anti-neutrophil cytoplasmic antibody against myeloperoxidase (MPO) was 204 U/ml. A renal biopsy specimen revealed necrotizing glomerulonephritis with crescent formation. However, immunofluorescence showed staining with IgG and C3 along capillary walls. IgG positivity included both IgG1 and IgG4. Electron microscopic examination disclosed both paramesangial and subepithelial deposits. This case suggests that rarely, MPO-ANCA-related crescentic glomerulonephritis may present nephrotic-range proteinuria and show immune deposits along capillary walls.