Clinical Outcome of Patients With Coexistent Antineutrophil Cytoplasmic Antibodies and Antibodies Against Glomerular Basement Membrane

Anti-glomerular Basement Membrane Glomerulonephritis: A Study in Real Life

Introduction

Anti-glomerular basement membrane (anti-GBM) disease is a severe entity with few therapeutic options including plasma exchange and immunosuppressive agents. The aim of this study was to analyze the clinical and pathological features that predict the evolution of end-stage kidney disease (ESKD) and the kidney survival in a cohort of patients with anti-GBM disease with renal involvement in real life.

Methods

A retrospective multicentre observational study including 72 patients from 18 nephrology departments with biopsy-proven anti-GBM disease from 1999 to 2019 was performed. Progression to ESKD in relation to clinical and histological variables was evaluated.

Results

Creatinine at admission was 8.6 (± 4) mg/dL and 61 patients (84.7%) required dialysis. Sixty-five patients (90.3%) underwent plasma exchange. Twenty-two patients (30.6%) presented pulmonary hemorrhage. Kidney survival was worse in patients with creatinine levels > 4.7 mg/dL (3 vs. 44% p < 0.01) and in patients with > 50% crescents (6 vs. 49%; p = 0.03). Dialysis dependence at admission and creatinine levels > 4.7 mg/dL remained independent significant predictors of ESKD in the multivariable analysis [HR (hazard ratio) 3.13 (1.25–7.84); HR 3 (1.01–9.14); p < 0.01]. The discrimination value for a creatinine level > 4.7 mg/dL and 50.5% crescents had an area under the curve (AUC) of 0.9 (95% CI 0.82–0.97; p < 0.001) and 0.77 (95% CI 0.56–0.98; p = 0.008), respectively. Kidney survival at 1 and 2 years was 13.5 and 11%, respectively. Patient survival at 5 years was 81%.

Conclusion

In real life, patients with severe anti-GBM disease (creatinine > 4.7 mg/dL and > 50% crescents) remained with devastating renal prognosis despite plasma exchange and immunosuppressive treatment. New therapies for the treatment of this rare renal disease are urgently needed.

Accuracy of Anti-GBM Antibodies in Diagnosing Anti-Glomerular Basement Membrane Disease: A Systematic Review and Meta-Analysis

BACKGROUND

The sensitivity and specificity of anti-glomerular basement membrane (GBM) antibodies have not been systematically analyzed. In this systematic review, we aimed to evaluate the diagnostic accuracy of anti-GBM antibodies for anti-GBM disease.

SUMMARY

Potential studies were searched using MEDLINE, Embase, the Cochrane Library, and the International Clinical Trials Registry Platform based on the index test and target condition. The inclusion criteria were prospective or retrospective cohort studies or case-control studies assessing the sensitivity and specificity of anti-GBM antibodies, and the reference standard was clinical diagnosis including biopsy results. The exclusion criteria were review articles, case reports, animal studies, and in vitro studies. Quality assessment was conducted based on the Quality Assessment of Diagnostic Accuracy Studies-2. The pooled estimates of sensitivity and specificity were calculated using a bivariate random-effects model. The overall quality was evaluated using the Grades of Recommendation, Assessment, Development, and Evaluation. Six studies (1,691 patients) and 11 index tests were included in our systematic review. A high risk of bias and concerns regarding the applicability of patient selection were noted because of the case-control design in 67% of the included studies. The pooled sensitivity and specificity were 93% (95% CI: 84-97%) and 97% (95% CI: 94-99%), respectively. The certainty of evidence was low because of the high risk of bias and indirectness. Key Messages: Anti-GBM antibodies may exhibit high sensitivity and specificity in the diagnosis of anti-GBM disease. Further cohort studies are needed to confirm their precise diagnostic accuracy and compare diagnostic accuracies among different immunoassays.

ANCA and anti-glomerular basement membrane double-positive patients: A systematic review of the literature

INTRODUCTION

Double-positive patients (DPP) exhibiting anti-glomerular basement membrane (GBM) and anti-neutrophil cytoplasmic antibodies (ANCAs) belong to an entity that is newly and poorly described, mainly in short series. We aimed to better characterize the epidemiological features, clinical presentation and therapeutic outcomes of these patients through a systematic review.

METHODS

We performed a systematic review of English-, German-, Spanish- and French-written publications from February 1987 to March 2020 reporting cases of DPP using the following databases: PubMed, Scielo, ScienceDirect, Google Scholar, The Cochrane Library, Open Grey, The Grey Literature Report, Clinicaltrials.gov and International Clinical Trial Registry Platform of the World Health Organization.

RESULTS

In total, 538 DPP were identified from 90 articles. Their clinical presentations were often severe, and the majority exhibited acute kidney failure (91.8%) with a median initial serum creatinine level of 873 μmol/L; 50.7% had alveolar haemorrhage. Other manifestations were present in 30.3% of DPP, mainly ear, nose, throat and articular manifestations. ANCAs were predominantly directed against MPO (n = 377/523; 72.1%) compared to PR3 (n = 107/523; 20.5%), with rare cases of triple positivity (n = 15/538; 2.9%). Although most patients received initial immunosuppressive therapy (n = 285/317; 89.9%), the one-year overall, renal and relapse-free survival rates were 64.8%, 38.7% and 71.1%, respectively.

CONCLUSION

DPP are associated with the characteristics of two eponymous vasculitis types, responsible for a poor overall and renal prognosis. Thus, simultaneous testing of both antibodies and systematic renal biopsy should be recommended in every patient with rapidly progressive glomerulonephritis to recognize this difficult-to-treat and rare disease.

Anti-glomerular basement membrane disease: A clinicomorphological study of 16 cases

Introduction

Antiglomerular basement membrane disease manifests as rapidly progressive glomerulonephritis and alveolar hemorrhage. It encompasses 10-15% of crescentic glomerulonephritis and is associated with poor outcome. In this study, we have elaborated on the clinical details, morphological features, and outcome of anti-GBM glomerulonephritis.

Materials and Methods

All the consecutive biopsy-proven cases of anti-GBM glomerulonephritis over a period of 4½ years were analyzed, retrospectively.

Results

Sixteen cases were diagnosed as anti-GBM glomerulonephritis during the study period. Twelve patients presented with rapidly progressive renal failure of which four patients required hemodialysis at the time of presentation. Goodpasture's syndrome was noted in two patients. Thirteen cases were positive for circulating anti-GBM antibodies and two patients showed double positivity for both anti-GBM antibodies and ANCA. Fifteen biopsies revealed crescentic glomerulonephritis with linear deposition of IgG along the glomerular basement membrane in all the 16 cases.

Conclusion

Renal biopsy analysis is important in the diagnosis of Anti GBM nephritis. Morphology is an important predictor of disease progression.

Severe Infection in Anti-Glomerular Basement Membrane Disease: A Retrospective Multicenter French Study

In patients presenting with anti-glomerular basement membrane (GBM) disease with advanced isolated kidney involvement, the benefit of intensive therapy remains controversial due to adverse events, particularly infection. We aim to describe the burden of severe infections (SI) (requiring hospitalization or intravenous antibiotics) and identify predictive factors of SI in a large cohort of patients with anti-GBM disease. Among the 201 patients (median [IQR] age, 53 [30–71] years) included, 74 had pulmonary involvement and 127 isolated glomerulonephritis. A total of 161 SI occurred in 116 patients during the first year after diagnosis. These infections occurred during the early stage of care (median [IQR] time, 13 [8–19] days after diagnosis) with mainly pulmonary (45%), catheter-associated bacteremia (22%) and urinary tract (21%) infections. In multivariable analysis, positive ANCA (HR [95% CI] 1.62 [1.07−2.44]; p = 0.02) and age at diagnosis (HR [95% CI] 1.10 [1.00–1.21]; p = 0.047) remained independently associated with SI. Age-adjusted severe infection during the first three months was associated with an increased three-year mortality rate (HR [95% CI] 3.13 [1.24–7.88]; p = 0.01). Thus, SI is a common early complication in anti-GBM disease, particularly in the elderly and those with positive anti-neutrophil cytoplasmic antibodies (ANCA). No significant association was observed between immunosuppressive strategy and occurrence of SI.

Diagnostic and management challenges in Goodpasture's (anti-glomerular basement membrane) disease

Goodpasture's or anti-glomerular basement membrane (GBM) disease is classically characterized by the presence of circulating autoantibodies directed against the non-collagenous domain of the α3 chain of type IV collagen, targeting glomerular and alveolar basement membranes, and associated with rapidly progressive crescentic glomerulonephritis, with alveolar haemorrhage in over half the patients. However, there are increasing examples of variants or atypical presentations of this disease, and novel therapeutic options have been proposed, which nephrologists should be aware of. The pathophysiology of this condition has been understood through molecular analysis of the antibody-antigen interactions and the use of human leucocyte antigen-transgenic animals, while the association of anti-GBM antibodies with anti-neutrophil cytoplasm antibodies and their combined impact on disease phenotype is increasingly recognized, providing some insights into the basis of glomerular damage and autoimmunity.

Anti-Glomerular Basement Membrane Disease

Anti-glomerular basement membrane (anti-GBM) disease is a rare autoimmune small vessel vasculitis characterized by autoreactivity to antigens in type IV collagen chains expressed in glomerular and alveolar basement membrane. The detection of circulating anti-GBM antibodies, which are shown to be directly pathogenic, is central to disease diagnosis. Clinically, anti-GBM disease usually presents with rapidly progressive glomerulonephritis with or without alveolar hemorrhage. Rapid diagnosis and early treatment are required to prevent mortality and to preserve renal function. Relapse in anti-GBM disease is uncommon. Variant and atypical forms of anti-GBM disease are increasingly recognised.

Immunoadsorption in Anti-GBM Glomerulonephritis: Case Report in a Child and Literature Review

Antiglomerular basement membrane glomerulonephritis (anti-GBM GN) is a rare autoimmune disease that is characterized by rapidly progressive glomerulonephritis that may be associated with pulmonary hemorrhage. Anti-GBM GN is caused by autoantibodies (classically type G immunoglobulin) directed against the α3 subunit of type IV collagen. Without any appropriate treatment, the disease is generally fulminant, and patient and kidney survival is poor. The current guidelines recommend the use of plasma exchanges and immunosuppressive drugs. Immunoadsorption (IA) can remove pathogenic IgGs from the circulation and do not require plasma infusions, contrary to plasma exchanges. IA has seldom been used in adult patients with good tolerance and efficiency. We report herein the first pediatric case successfully treated with IA combined with immunosuppressive drugs in a 7-year-old girl who presented acute kidney injury (estimated glomerular filtration rate 38 mL/minute/1.73 m²). A kidney biopsy revealed numerous >80% glomerular crescents and linear IgG deposits along the glomerular basement membrane. Ten IA sessions led to rapid and sustained clearance of autoantibodies and improvement of kidney function until 21 months after onset (glomerular filtration rate 87 mL/minute/1.73 m²). No adverse effect was noted. This report adds to the growing body of evidence suggesting IA as a therapeutic alternative to plasma exchanges in anti-GBM GN. The other 27 published pediatric cases of anti-GBM GN are reviewed.

Patients double-seropositive for ANCA and anti-GBM antibodies have varied renal survival, frequency of relapse, and outcomes compared to single-seropositive patients

Co-presentation with both ANCA and anti-GBM antibodies is thought to be relatively rare. Current studies of such ‘double-positive’ cases report small numbers and variable outcomes. To study this further we retrospectively analyzed clinical features and long-term outcomes of a large cohort of 568 contemporary patients with ANCA-associated vasculitis, 41 patients with anti-GBM disease, and 37 double-positive patients with ANCA and anti-GBM disease from four European centers. Double-positive patients shared characteristics of ANCA-associated vasculitis (AAV), such as older age distribution and longer symptom duration before diagnosis, and features of anti-GBM disease, such as severe renal disease and high frequency of lung hemorrhage at presentation. Despite having more evidence of chronic injury on renal biopsy compared to patients with anti-GBM disease, double-positive patients had a greater tendency to recover from being dialysis-dependent after treatment and had intermediate long-term renal survival compared to the single-positive patients. However, overall patient survival was similar in all three groups. Predictors of poor patient survival included advanced age, severe renal failure, and lung hemorrhage at presentation. No single-positive anti-GBM patients experienced disease relapse, whereas approximately half of surviving patients with AAV and double-positive patients had recurrent disease during a median follow-up of 4.8 years. Thus, double-positive patients have a truly hybrid disease phenotype, requiring aggressive early treatment for anti-GBM disease, and careful long-term follow-up and consideration for maintenance immunosuppression for AAV. Since double-positivity appears common, further work is required to define the underlying mechanisms of this association and define optimum treatment strategies.

A case of PR3-ANCA-positive anti-GBM disease associated with intrarenal arteritis and thrombotic microangiopathy

Coexistence of anti-glomerular basement membrane (anti-GBM) disease with anti-neutrophil cytoplasmic antibody (ANCA) is occasionally reported and termed "double positive" disease. Interestingly, the majority of "double positive" ANCA is myeloperoxidase (MPO)-ANCA, and some of the MPO-ANCA-positive cases reveal intrarenal arteritis indicating an ANCA-associated renal lesion. In contrast, proteinase 3 (PR3)-ANCA-positive "double positive" disease had rarely been reported, and as far as we know, none of the cases showed intrarenal arteritis. Herein, we report a case of PR3-ANCA-positive "double positive" anti-GBM disease presenting with pulmonary-renal syndrome and hemolytic uremic syndrome. The kidney biopsy showed crescentic glomerulonephritis, intrarenal arteritis, and thrombotic microangiopathy. This case newly describes PR3-ANCA-associated intrarenal arteritis in "double positive" anti-GBM disease.

Spatial and Temporal Clustering of Anti-Glomerular Basement Membrane Disease

BACKGROUND AND OBJECTIVES

An environmental trigger has been proposed as an inciting factor in the development of anti-GBM disease. This multicenter, observational study sought to define the national incidence of anti-GBM disease during an 11-year period (2003-2014) in Ireland, investigate clustering of cases in time and space, and assess the effect of spatial variability in incidence on outcome.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We ascertained cases by screening immunology laboratories for instances of positivity for anti-GBM antibody and the national renal histopathology registry for biopsy-proven cases. The population at risk was defined from national census data. We used a variable-window scan statistic to detect temporal clustering. A Bayesian spatial model was used to calculate standardized incidence ratios (SIRs) for each of the 26 counties.

RESULTS

Seventy-nine cases were included. National incidence was 1.64 (95% confidence interval [95% CI], 0.82 to 3.35) per million population per year. A temporal cluster (n=10) was identified during a 3-month period; six cases were resident in four rural counties in the southeast. Spatial analysis revealed wide regional variation in SIRs and a cluster (n=7) in the northwest (SIR, 1.71; 95% CI, 1.02 to 3.06). There were 29 deaths and 57 cases of ESRD during a mean follow-up of 2.9 years. Greater distance from diagnosis site to treating center, stratified by median distance traveled, did not significantly affect patient (hazard ratio, 1.80; 95% CI, 0.87 to 3.77) or renal (hazard ratio, 0.76; 95% CI, 0.40 to 1.13) survival.

CONCLUSIONS

To our knowledge, this is the first study to report national incidence rates of anti-GBM disease and formally investigate patterns of incidence. Clustering of cases in time and space supports the hypothesis of an environmental trigger for disease onset. The substantial variability in regional incidence highlights the need for comprehensive country-wide studies to improve our understanding of the etiology of anti-GBM disease.

Crescentic glomerulonephritis with dual positive anti-GBM and C-ANCA/PR3 antibodies

Antiglomerular basement membrane (anti-GBM) antibodies are more often accompanied by myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) than by proteinase 3 antineutrophil cytoplasmic antibody (PR3-ANCA). Both disease processes can affect the kidneys and/or the lungs. Patients with dual positive disease may have an atypical presentation which may delay diagnosis and treatment. Here we report a case of crescentic glomerulonephritis associated with positive PR3-ANCA and anti-GBM antibodies who underwent both lung and kidney biopsies.

Presence of Anti-Glomerular Basement Membrane Antibodies and Myeloperoxidase Anti-Neutrophilic Cytoplasmic Antibodies in a Case of Rapidly Progressive Glomerulonephritis

A 69-year-old male had initially presented with low-grade proteinuria, microhematuria, and a positive myeloperoxidase anti-neutrophilic antibody (ANCA). He subsequently developed deterioration of kidney function and developed uremic symptoms. Creatinine was 486.2 μmol/L (5.5 mg/dL). Anti-MPO was positive (titer >8 U, normal <0.4). He was clinically diagnosed with rapidly proliferative glomerulonephritis most likely due to ANCA vasculitis. He received three doses of pulse methylprednisolone therapy. Kidney biopsy showed pauci-immune glomerulonephritis. Immunofluorescence was positive for faint linear IgG staining of glomerular basement membrane (GBM). Anti-GBM antibody was positive 2.1 U (normal <1). He was started on high-dose oral steroids; monthly intravenous cyclophosphamide and plasmapheresis were also initiated. His symptoms improved and creatinine is 247.5 μmol/L (2.8 mg/dL). His repeat anti-GBM antibody was negative. This is a rare case of rapidly progressive glomerulonephritis due to dual MPO-ANCA antibodies and anti-GBM antibodies (DAV).

Coexistence of Anti-Glomerular Basement Membrane Antibodies and Anti-Neutrophil Cytoplasmic Antibodies in a Child With Human Leukocyte Antigen Susceptibility and Detailed Antibody Description: A Case Report

Anti-glomerular basement membrane (anti-GBM) disease and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis both could cause rapidly progressive glomerulonephritis. The coexistence of ANCAs and anti-GBM antibodies was known as "double positive," which was extremely rare in children. We report a pediatric case with coexistence of ANCAs and anti-GBM antibodies. A 6-year-old girl presented with acute renal failure, hematuria, proteinuria, and oliguria. She was double positive of ANCAs specific to myeloperoxidase, and anti-GBM antibodies. Kidney biopsy confirmed linear immunoglobulin (Ig)G deposit along GBM and 100% of crescent formation in glomeruli; among them 83.3% were cellular crescents. Human leukocyte antigen (HLA) gene typing showed DRB1*1501, an allele strongly associated with anti-GBM disease, and DRB1*0405, an independent risk factor for renal failure in patients with ANCA-associated vasculitis. The titer of anti-GBM antibodies was 1:800, and the predominant IgG subclass was IgG1, which was closely related with severe kidney injury and worse outcome. The target antigen of anti-GBM antibodies was restricted on the noncollagen domain 1 of the α3 chain of type IV collagen (α3[IV]NC1), with recognitions to both epitopes, EA (α317-31) and EB (α3127-141). This is the first reported pediatric case with coexistence of ANCAs and anti-GBM antibodies, in which the HLA typing and immunologic characters of autoantibodies were identified. The findings on this early-onset patient are meaningful for understanding the mechanisms of both anti-GBM disease and ANCA-associated vasculitis.

Comparison of double filtration plasmapheresis with immunoadsorption therapy in patients with anti-glomerular basement membrane nephritis

Background

Double filtration plasmapheresis (DFPP) and (IA) are both used to clear antibody. However, the clinical efficacy and safety of DFPP in patients with anti-glomerular basement membrane (anti-GBM) disease are unclear.

Methods

The 28 enrolled patients diagnosed serologically and pathologically with anti-GBM disease from 2003 to 2013 included 16 treated with DFPP and 12 with IA, with all patients administered immunosuppressive agents. DFPP consisted of an EC50W filter for plasma separation and an EC20W filter for plasma fractionation. A double volume of plasma was processed, and each patient received a 30–40 g human albumin supplement during each session. IA consisted of 10 cycles per session, with 8–10 sessions performed daily or every other day and each session regenerating 30–60 L of plasma. Serum anti-GBM antibodies and IgG were measured, and urinary and blood tests were performed, before and after each procedure. Renal function and outcome were determined.

Results

The 28 patients consisted of 13 males and 15 females, of median age 44.5 years (range, 22.5–57 years). Six patients had pulmonary hemorrhage and 18 had serum creatinine concentrations >500 umol/L. The average serum creatinine concentration at early onset of disease was 525 umol/L while the peak concentration was 813 umol/L. All patients showed progressive increases in serum creatinine and required CRRT during the course of disease. Pathological examination showed an average 73.9% of crescents (range, 54.6–95.4%).The clinical and pathological features of the DPPP and IA groups were similar. Efficacy of clearing anti-GBM antibody was similar in the two groups (59.0 vs. 71.2%, P = 1.00), although fewer patients in the DFPP group experienced reduced IgG (62.7 vs. 83.5%, p = 0.002). One patient each had a pulmonary hemorrhage and a subcutaneous hemorrhage during treatment, but there were no other serious complications. At the end of follow-up, patient survival and renal survival were similar in the DFPP and IA groups.

Conclusion

DPPP plus immunosuppressive therapy efficiently and safely removed anti-GBM antibodies. The fewer plasma-associated side effects and reduced loss of IgG suggest that DFPP may be a better treatment choice for anti-GBM disease, especially in patients with insufficient plasma.

Pulmonary renal syndrome in a child with coexistence of anti-neutrophil cytoplasmic antibodies and anti-glomerular basement membrane disease: case report and literature review

BACKGROUND

Pulmonary renal syndrome (PRS), denoting the presence of diffuse alveolar hemorrhage and glomerulonephritis as manifestations of systemic autoimmune disease, is very rare in childhood. The coexistence of circulating anti-neutrophil cytoplasmic antibody (ANCA) and anti-glomerular basement membrane (GBM) disease in children affected by this syndrome is exceptional, with unfavorable outcome in five out of seven patients reported to date. We describe a child with PRS associated with both circulating anti-myeloperoxidase (anti-MPO) ANCA and anti-GBM disease on renal biopsy who was successfully treated with immunosuppressive therapy.

CASE PRESENTATION

A 10-year old girl presented with fever, fatigue, malaise, and pallor followed by hemoptysis and severe anemia. Diffuse alveolar hemorrhage was revealed on fiberoptic bronchoscopy. Renal findings consisted of microscopic hematuria, moderate proteinuria, and anti-GBM disease on renal biopsy. ANCA with anti-MPO specificity were present whereas anti-GBM antibodies were on borderline for positivity. Methyl-prednisolone pulses followed by prednisone led to cessation of hemoptysis, marked improvement of lung fuction, and normal finding on chest x-ray within 10 days. An immunosuppressive regimen was then given consisting of prednisone daily for 4 weeks with subsequent taper on alternate day, i.v. cyclophosphamide pulses monthly for 6 doses, followed by mycophenolate mofetil that resulted in normal lung function tests, hemoglobin concentration, and anti-MPO level within four subsequent weeks. During 10-months of follow-up she remained well, her blood pressure and renal function tests were normal, and proteinuria and hematuria gradually resolved.

CONCLUSION

We report a child with an exceptionally rare coexistence of circulating ANCA and anti-GBM disease manifesting as PRS in whom renal disease was not the prominent part of clinical presentation, contrary to other reported pediatric patients. A review of literature on disease with double positive antibodies is also presented. Evaluation of a patient with PRS should include testing for presence of different antibodies. An early diagnosis and rapid institution of aggressive immunosuppressive therapy can induce remission and preserve renal function. Renal prognosis depends on the extent of kidney injury at diagnosis and appropriate treatment.

Basic and translational concepts of immune-mediated glomerular diseases

Genetically modified immune responses to infections and self-antigens initiate most forms of GN by generating pathogen- and danger-associated molecular patterns that stimulate Toll-like receptors and complement. These innate immune responses activate circulating monocytes and resident glomerular cells to release inflammatory mediators and initiate adaptive, antigen-specific immune responses that collectively damage glomerular structures. CD4 T cells are needed for B cell-driven antibody production that leads to immune complex formation in glomeruli, complement activation, and injury induced by both circulating inflammatory and resident glomerular effector cells. Th17 cells can also induce glomerular injury directly. In this review, information derived from studies in vitro, well characterized experimental models, and humans summarize and update likely pathogenic mechanisms involved in human diseases presenting as nephritis (postinfectious GN, IgA nephropathy, antiglomerular basement membrane and antineutrophil cytoplasmic antibody-mediated crescentic GN, lupus nephritis, type I membranoproliferative GN), and nephrotic syndrome (minimal change/FSGS, membranous nephropathy, and C3 glomerulopathies). Advances in understanding the immunopathogenesis of each of these entities offer many opportunities for future therapeutic interventions.

Crescentic Glomerulonephritis with Anti-GBM and p-ANCA Antibodies

We are presenting a case of renal failure with anti-GBM and p-ANCA antibodies positive. Patients with dual antibodies are considered to be a vasculitis-variant of anti-GBM antibody nephritis. These patients may have atypical presentation and it may delay diagnosis and treatment. Recurrence rate is higher in these patients. We reviewed the literature of cases and studies on cresenteric glomerulonephritis with anti-GBM and p-ANCA positive patients. We recommend that patients suspected with pulmonary-renal syndrome should be checked for anti-GBM and p-ANCA antibodies, should undergo renal biopsy and should should have close long term follow up to watch for recurrence.

Anti-hLAMP2-antibodies and dual positivity for anti-GBM and MPO-ANCA in a patient with relapsing pulmonary-renal syndrome

BACKGROUND

Pulmonary-renal syndrome associated with anti-glomerular basement membrane (GBM) antibodies, also known as Goodpasture's syndrome, is a rare but acute and life-threatening condition. One third of patients presenting as anti-GBM antibody positive pulmonary-renal syndrome or rapidly progressive glomerulonephritis are also tested positive for anti-neutrophil cytoplasmic antibodies (ANCA). Whilst anti-GBM disease is considered a non-relapsing condition, the long-term course of double-positive patients is less predictable.

CASE PRESENTATION

We report a patient with such dual positivity, who presented with pulmonary hemorrhage, crescentic glomerulonephritis and membranous nephropathy. Plasmapheresis in combination with immunosuppressive therapy led to a rapid remission but the disease relapsed after two years. The serum of the patient was tested positive for antibodies to human lysosomal membrane protein 2 (hLAMP2), a novel autoantigen in patients with active small-vessel vasculitis (SVV). The anti-hLAMP2 antibody levels correlated positively with clinical disease activity in this patient.

CONCLUSION

We hypothesize that this antibody may indicate a clinical course similar to ANCA-associated vasculitis in double-positive patients. However, this needs to be confirmed on comprehensive patient cohorts.

Pulmonary vasculitis: clinical presentation, differential diagnosis, and management

This review focuses on vasculitides with prominent pulmonary manifestations and discusses key contributions from the recent literature. Pulmonary vasculitis should be considered when clinical findings include alveolar hemorrhage, nodular and cavitary lung disease, airway stenosis, pulmonary artery aneurysms, or pulmonary artery stenosis. The differential diagnostic considerations for common clinical presentations of vasculitis in the lung are important, and several recent additions are discussed. Treatment for established pulmonary vasculitis is effective and has decreased the morbidity and mortality associated with these diseases while introducing an increased risk of infectious complications. Advances in immunosuppressive therapy have improved treatment of refractory disease and are likely to change initial treatment strategies in the future.

Recovery of renal function in a dialysis-dependent patient with microscopic polyangiitis and both myeloperoxidase anti-neutrophil cytoplasmic antibodies and anti-glomerular basement membrane antibodies

A 40-year-old man with microscopic polyangiitis developed both myeloperoxidase anti-neutrophil cytoplasmic antibodies (90 EU) and anti-glomerular basement membrane antibodies (134 EU)-positive rapidly progressive glomerulonephritis and heparin-induced thrombocytopenia. Although the patient initially showed no signs of improvement, persistent therapy including 1 g/day intravenous methylprednisolone, 50 mg/day oral prednisolone, plasma exchange, and 900 mg/day intravenous cyclophosphamide resulted in the normalization of both titers, recovery of renal function, and discontinuation of dialysis. Though previous studies showed poor outcomes in such "double-positive" patients, aggressive immunosuppression in younger patients may result in the recovery of renal function, even in those with severe renal dysfunction.

Diagnostic approach to ANCA-associated vasculitides

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) include Wegener's granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome. Given their rarity, protean clinical manifestations, imperfect diagnostic tests, and wide differential diagnosis, they pose a diagnostic challenge even to experienced clinicians. This article describes diagnostic approaches for patients suspected of having one of the ANCA-associated vasculitides. The clinical findings at presentation, the role of laboratory and imaging tests, and the importance of tissue diagnosis are presented. In each section, issues relevant to the differential diagnosis of AAV are discussed.

Microscopic polyangiitis

In 1923, Friedrich Wohlwill described two patients with a "microscopic form of periarteritis nodosa," which was distinct from the classical form. This disease, now known as microscopic polyangiitis (MPA), is a primary systemic vasculitis characterized by inflammation of the small-caliber blood vessels and the presence of circulating antineutrophil cytoplasmic antibodies. Typically, microscopic polyangiitis presents with glomerulonephritis and pulmonary capillaritis, although involvement of the skin, nerves, and gastrointestinal tract is not uncommon. Treatment of MPA generally requires use of a cytotoxic agent (such as cyclophosphamide) in addition to high-dose glucocorticoids. Recent research has focused on identifying alternate treatment strategies that minimize or eliminate exposure to cytotoxic agents. This article reviews the history, pathogenesis, clinical manifestations, and treatment of MPA.

GLOMERULONEPHRITIS AND THE NEPHROTIC SYNDROME IN PREGNANCY

Glomerulonephritis (GN) may be manifest clinically in several ways. It may be asymptomatic and associated with only minor urinary dipstick abnormalities, GN may present with one of the classic renal nephritic or nephrotic syndromes, or may be associated with progressive chronic kidney disease with hypertension and the gradual development of uraemia, or it may present with fulminating life threatening illness with severe acute kidney injury. The development of GN may indicate a primary renal limited disease, or may be secondary in association with systemic diseases such as systemic lupus erythematosus (SLE), myeloma, infections or diabetes. Although immunological abnormalities underlie the development of many forms of GN, precise pathogenic mechanisms remain unclear and diagnostic labels may simply reflect a description of the glomerular histological changes observed (Table 1).