Characteristics and outcome of crescentic glomerulonephritis in patients with both antineutrophil cytoplasmic antibody and anti-glomerular basement membrane antibody

Clinical characteristics and outcome of double-seropositive patients with anti-glomerular basement membrane antibodies and anti-neutrophil cytoplasmic antibodies

OBJECTIVE

To explore the clinical characteristics of double-seropositive patients (DPPs) with anti-glomerular basement membrane (Anti-GBM) antibodies and anti-neutrophil cytoplasmic antibodies (ANCA).

METHODS

We collected patients with both ANCA and anti-GBM positive glomerulonephritis who were hospitalized in the Department of Nephrology at the First Affiliated Hospital of Nanjing Medical University from January 2010 to August 2022. Retrospective analysis of the baseline clinical characteristics of patients and follow-up to explore relevant factors affecting renal and patient survival.

RESULTS

A total of 386 patients, including 69 ANCA negative anti-GBM glomerulonephritis patients, 296 anti-GBM negative ANCA associated vasculitis (AAV) patients, and 21 DPPs were enrolled in this study. Among the 21 DPPs aged 68.0 years (59.5, 74.0), there were 11 males and 10 females. The median serum creatinine at diagnosis was 629.0 (343.85, 788.75) μmol/L, and the median eGFR (CKD-EPI) was 7.58 (4.74, 13.77) mL/min. Fifteen cases (71.4 %) underwent initial RRT. After a follow-up of 40.0 (11.0, 73.0) months, 13 out of 21 DPPs (61.9 %) received maintenance RRT, while 49 out of 69 (71.0 %) ANCA negative anti-GBM-GN patients and 124 out of 296 (41.9 %) anti-GBM negative AAV patients received maintenance RRT (P < 0.001). Kaplan-Meier survival analysis showed that DPPs and ANCA negative anti-GBM-GN patients were more likely to progress to ESRD than anti-GBM negative AAV patients (P = 0.001). Among the 21 patients with DPPs, renal survival was significantly better in patients with better initial renal function, including those who did not receive initial RRT (P = 0.003), with lower serum creatinine levels (Cr < 629.0 μmol/L, P = 0.004) and higher eGFR levels (eGFR ≥ 7.60 ml/min, P = 0.005) than those with poor initial renal function. At the end of follow-up, 14 out of 21 DPPs (66.7 %) survived. Survival analysis showed no significant difference among patients in DPPs group, ANCA negative anti-GBM-GN group, and anti-GBM negative AAV group.

CONCLUSIONS

DPPs and ANCA negative anti-GBM-GN patients were more likely to progress to ESRD than anti-GBM negative AAV patients. In DPPs, the poor renal function at diagnosis might be a risk factor associated with poor renal survival.

Epidemiology, clinical features, risk factors, and outcomes in anti-glomerular basement membrane disease: A systematic review and meta-analysis

Anti-glomerular basement membrane (GBM) disease is a small-vessel vasculitis that represents the most aggressive form of autoimmune glomerulonephritis. The study aimed to investigate the prevalence, clinical characteristics, risk factors, and outcomes of anti-GBM disease through a systematic review and meta-analysis involving 47 studies with 2830 patients. The overall incidence of anti-GBM disease ranged from 0.60 to 1.79 per million population per annum. In rapidly progressive glomerulonephritis and crescentic glomerulonephritis, the pooled incidence rates were 8.0% and 12.8%, respectively. The pooled prevalence rates of anti-GBM antibodies, antineutrophil cytoplasmic antibodies (ANCA), and lung hemorrhage were 88.8%, 27.4%, and 32.6%, respectively. Patients with combined ANCA positivity demonstrated a prognosis comparable to those patients with only anti-GBM antibodies, though with differing clinical features. The pooled one-year patient and kidney survival rates were 76.2% and 30.2%, respectively. Kidney function on diagnosis and normal glomeruli percentage were identified as strong prognostic factors. This study represents the first comprehensive meta-analysis on anti-GBM disease, providing insights into its management. However, caution is warranted in interpreting some results due to the observational nature of the included studies and high heterogeneity.

Application of nanotechnology in the treatment of glomerulonephritis: current status and future perspectives

Glomerulonephritis (GN) is the most common cause of end-stage renal failure worldwide; in most cases, it cannot be cured and can only delay the progression of the disease. At present, the main treatment methods include symptomatic therapy, immunosuppressive therapy, and renal replacement therapy. However, effective treatment of GN is hindered by issues such as steroid resistance, serious side effects, low bioavailability, and lack of precise targeting. With the widespread application of nanoparticles in medical treatment, novel methods have emerged for the treatment of kidney diseases. Targeted transportation of drugs, nucleic acids, and other substances to kidney tissues and even kidney cells through nanodrug delivery systems can reduce the systemic effects and adverse reactions of drugs and improve treatment effectiveness. The high specificity of nanoparticles enables them to bind to ion channels and block or enhance channel gating, thus improving inflammation. This review briefly introduces the characteristics of GN, describes the treatment status of GN, systematically summarizes the research achievements of nanoparticles in the treatment of primary GN, diabetic nephropathy and lupus nephritis, analyzes recent therapeutic developments, and outlines promising research directions, such as gas signaling molecule nanodrug delivery systems and ultrasmall nanoparticles. The current application of nanoparticles in GN is summarized to provide a reference for better treatment of GN in the future.

Three Diseases Mediated by Different Immunopathologic Mechanisms-ANCA-Associated Vasculitis, Anti-Glomerular Basement Membrane Disease, and Immune Complex-Mediated Glomerulonephritis-A Common Clinical and Histopathologic Picture: Rapidly Progressive Crescentic Glomerulonephritis

Immune mechanisms play an important role in the pathogenesis of glomerulonephritis (GN), with autoimmunity being the main underlying pathogenetic process of both primary and secondary GN. We present three autoimmune diseases mediated by different autoimmune mechanisms: glomerulonephritis in vasculitis mediated by anti-neutrophil cytoplasmic antibodies (ANCAs), glomerulonephritis mediated by anti-glomerular basement membrane antibodies (anti-GBM antibodies), and immune complex-mediated glomerulonephritis. Some of these diseases represent a common clinical and histopathologic scenario, namely rapidly progressive crescentic glomerulonephritis. This is a severe illness requiring complex therapy, with the main role being played by therapy aimed at targeting immune mechanisms. In the absence of immune therapy, the crescents, the characteristic histopathologic lesions of this common presentation, progress toward fibrosis, which is accompanied by end-stage renal disease (ESRD). The fact that three diseases mediated by different immunopathologic mechanisms have a common clinical and histopathologic picture reveals the complexity of the relationship between immunopathologic mechanisms and their clinical expression. Whereas most glomerular diseases progress by a slow process of sclerosis and fibrosis, the glomerular diseases accompanied by glomerular crescent formation can progress, if untreated, in a couple of months into whole-nephron glomerulosclerosis and fibrosis. The outcome of different immune processes in a common clinical and histopathologic phenotype reveals the complexity of the relationship of the kidney with the immune system. The aim of this review is to present different immune processes that lead to a common clinical and histopathologic phenotype, such as rapidly progressive crescentic glomerulonephritis.

Unleashing the power of complement activation: unraveling renal damage in human anti-glomerular basement membrane disease

Anti-glomerular basement membrane (GBM) disease is a rare but life-threatening autoimmune disorder characterized by rapidly progressive glomerulonephritis with or without pulmonary hemorrhage. Renal biopsies of anti-GBM patients predominantly show linear deposition of IgG and complement component 3 (C3), indicating a close association between antigen-antibody reactions and subsequent complement activation in the pathogenesis of the disease. All three major pathways of complement activation, including the classical, lectin, and alternative pathways, are involved in human anti-GBM disease. Several complement factors, such as C3, C5b-9, and factor B, show a positive correlation with the severity of the renal injury and act as risk factors for renal outcomes. Furthermore, compared to patients with single positivity for anti-GBM antibodies, individuals who are double-seropositive for anti-neutrophil cytoplasmic antibody (ANCA) and anti-GBM antibodies exhibit a unique clinical phenotype that lies between ANCA-associated vasculitis (AAV) and anti-GBM disease. Complement activation may serve as a potential "bridge" for triggering both AAV and anti-GBM conditions. The aim of this article is to provide a comprehensive review of the latest clinical evidence regarding the role of complement activation in anti-GBM disease. Furthermore, potential therapeutic strategies targeting complement components and associated precautions are discussed, to establish a theoretical basis for complement-targeted therapies.

Clinical features and prognosis of MPO-ANCA and anti-GBM double-seropositive patients

BACKGROUND

Several lines of evidence implicate that there are distinct differences between patients with myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA) and anti-glomerular basement membrane (GBM) antibody double-seropositive patients (DPPs) and single-positive patients. Hence, we conducted a retrospective study from a single center in China to analyze the clinical and pathological features, and prognosis of DPPs.

METHODS

109 patients with MPO-ANCA-associated vasculitis (MPO-AAV), 20 DPPs and 23 patients diagnosed with anti-GBM disease from a large center in China were included in this study. The ratio of patients with renal biopsy in three groups were 100%, 50% and 100%, respectively. Their clinical and pathological characteristics, and outcomes were analyzed. The intensity of immune deposits in the kidney at diagnosis was detected by immunofluorescence (IF). Furthermore, multivariate Cox hazard model analysis was used to assess the clinical and histological predictors of end-stage renal disease (ESRD) and death for DPPs.

RESULTS

In our study, we found that patients in the DPPs group were older than the other two groups (p = 0.007, MPO-AAV vs. DPPs; p < 0.001, DPPs vs. anti-GBM). The DPPs group had a higher value of serum creatinine (p = 0.041) and lower estimated glomerular filtration rate (eGFR) (p = 0.032) compared with MPO-AAV patients. On the contrary, the DPPs group had a lower serum creatinine (p = 0.003) compared with patients with anti-GBM group. The proportion of patients with cardiac system involvement in the DPPs group was higher than anti-GBM patients (p = 0.014). Cellular crescents could be generally observed in renal biopsy of DPPs and patients with anti-GBM glomerulonephritis. In addition, Bowman's capsule rupture was more common in DPPs than MPO-AAV patients (p = 0.001). MPO-AAV had a better renal and overall survival outcome than DPPs (p < 0.001). There was no significant difference of renal and overall survival outcome between DPPs and patients with anti-GBM disease. The incidence of ESRD in DPPs was negatively associated with lymphocyte count (HR 0.153, 95% CI 0.027 to 0.872, p = 0.034) and eGFR (HR 0.847, 95% CI 0.726 to 0.989, p = 0.036). Elevated serum creatinine was confirmed as a risk factor of both renal (HR 1.003, 95% CI 1.000 to 1.005, p = 0.019) and patient survival in DPPs (HR1.461, 95% CI 1.050 to 2.033, p = 0.024).

CONCLUSION

In summary, compared with anti-GBM disease, DPPs tended to involve multi-organ damage rather than limited to the kidney. It is highlighted that serologic DPPs have a worse renal and patient prognosis than MPO-AAV. Moreover, we found that the risk factors of renal survival of DPPs include low lymphocyte count, elevated serum creatinine and reduced eGFR, and serum creatinine can predict patient survival.

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.

Renal and overall outcomes of double-positive (ANCA and anti-GBM antibodies) patients compared to ANCA-associated vasculitis patients with severe renal involvement: A multicenter retrospective study with systematic renal pathology analysis

Objective: Double-positive patients (DPPs), combining serum and/or histological findings for glomerular basement membrane (GBM) disease and anti-neutrophil cytoplasmic antibodies (ANCAs), are rare and poorly described. This study aimed to compare characteristics between DPPs and ANCA-associated vasculitis (AAV) patients with severe renal involvement.Method: This retrospective multicentre study compared 33 DPPs and 45 AAV patients with severe renal involvement (serum creatinine > 300 μmol/L), all with biopsy-proven nephropathy.Results: All DPPs (including 18% exhibiting negative serum anti-GBM antibodies) presented severe acute kidney failure with histological GBM involvement. Compared to AAV patients, they had higher serum creatinine (719 vs 501 μmol/L; p = 0.006) and a higher proportion of patients requiring initial renal replacement therapy (82% vs 36%; p < 0.001). Berden classification differed significantly (p = 0.003), with more crescentic glomerulonephritis and fewer sclerotic lesions in DPPs. One-year renal survival was significantly lower in DPPs than in AAV patients (27% vs 64%; p < 0.0002). With comparable proportions of ANCA subtypes (two-thirds with anti-myeloperoxidase autoantibodies), numbers of extrarenal manifestations (mostly pulmonary in two-thirds), remission-inducing immunosuppressants, and median follow-ups (3 years) between groups, relapse rates were similar: 9.1% of DPPs and 10% of AAV patients.Conclusion: Although DPPs have features of both kinds of vasculitis, the anti-GBM component is the dominant phenotype, with more severe renal presentation and prognosis compared to AAV patients with severe renal failure. Simultaneous testing of both antibodies and systematically performed renal biopsy should be recommended in all rapidly progressing glomerulonephritis patients to recognize this difficult-to-treat, rare disease.

A Rare Case of Double Antibody-Positive Rapidly Progressive Glomerulonephritis: A Therapeutic Challenge

Crescentic glomerulonephritis, also known as rapidly progressive glomerulonephritis, is a syndrome characterized by progressive and rapid deterioration of renal function over the course of weeks to months. Oliguria, hematuria, azotemia, and hypertension are characteristic features of this condition. Crescentic glomerulonephritis is further classified according to the staining pattern on immunofluorescence. In rare instances, a mixed pattern of injury is encountered as in the case of double antibody-positive rapidly progressive glomerulonephritis (RPGN). This case illustrates the challenge in treatment of double antibody-positive RPGN in an elderly female with no previous renal disease. The patient was found to be positive for anti-GBM antibody and MPO-ANCA. Treatment was initially targeted against MPO-ANCA as the biopsy was most consistent with this process; however, the patient failed to respond to treatment and was subsequently transitioned to oral cyclophosphamide directed against anti-GBM disease. In cases of doubly antibody-positive RPGN with anti-GBM disease and ANCA-associated vasculitis, initial treatment should focus on inducing remission of anti-GBM disease as double antibody-positive disease often presents with the aggressive morbidity and mortality seen in anti-GBM disease, and the chronic risk of relapse seen in ANCA-mediated vasculitis.

Atypical anti-glomerular basement membrane disease with anti-GBM antibody negativity and ANCA positivity: a case report

BACKGROUND

Anti-glomerular basement membrane (anti-GBM) disease is an organ-specific autoimmune disease that involves the lung and kidneys and leads to rapid glomerulonephritis progression, with or without diffuse alveolar hemorrhage, and even respiratory failure. Classic cases of anti-GBM disease are diagnosed based on the presence of the anti-GBM antibody in serum samples and kidney or lung biopsy tissue samples. However, atypical cases of anti-GBM disease are also seen in clinical practice.

CASE PRESENTATION

We herein report the rare case of a patient with atypical anti-GBM disease whose serum was negative for the anti-GBM antibody but positive for the myeloperoxidase (MPO) anti-neutrophil cytoplasmic antibody (p-ANCA) and another atypical ANCA. Laboratory test results showed severe renal insufficiency with a creatinine level of 385 μmol/L. Renal biopsy specimen analysis revealed 100% glomeruli with crescents; immunofluorescence showed immunoglobulin G (IgG) linearly deposited alongside the GBM. Finally, the patient was discharged successfully after treatment with plasmapheresis, methylprednisolone and prednisone.

CONCLUSION

This patient, whose serum was negative for the anti-GBM antibody but positive for p-ANCA and another atypical ANCA, had a rare case of anti-GBM disease. Insights from this unusual case might help physicians diagnose rare forms of glomerulonephritis and treat affected patients in a timely manner.

Anti-neutrophil cytoplasmic antibody testing by indirect immunofluorescence: Computer-aided versus conventional microscopic evaluation of routine diagnostic samples from patients with vasculitis or other inflammatory diseases

BACKGROUND

Detection of anti-neutrophil cytoplasmic antibodies (ANCA) by indirect immunofluorescence assays (IFA) is of diagnostic importance in vasculitides and some other inflammatory diseases. Automation of IFA may be beneficial in high-throughput clinical laboratories. An analytical appraisal of the EUROPattern (EPa) automated microscope and image analysis system has not been reported in a routine clinical laboratory setting testing samples from both vasculitis and non-vasculitis patients.

METHODS

Results of EPa and on-screen ANCA pattern recognition of 568 consecutive routine serum samples were compared to those of conventional visual evaluation.

RESULTS

Agreement of discrimination between negative and non-negative samples was 86.1% comparing EPa and conventional reading, and it increased to 96.7% after on-screen user validation. Importantly, from the 334 samples classified as negative by EPa 328 (98.2%) were also negative by conventional evaluation. Pattern recognition showed 'moderate' agreement between classical microscopic and EPa analysis (κ = 0.446) and 'very good' agreement after user validation (κ = 0.900). Misclassification by EPa was dominantly due to the presence of anti-nuclear/cytoplasmic antibodies (incorrect pattern, 80/568) and the lower fluorescence cut-off of the automated microscope (false positives, 73/568).

CONCLUSIONS

Automated ANCA testing by EPa is a reliable alternative of classical microscopic evaluation, though classification of sera needs correction by trained personnel during on-screen validation.

2020 international consensus on ANCA testing beyond systemic vasculitis

This document follows up on a 2017 revised international consensus on anti-neutrophil cytoplasm antibodies (ANCA) testing in granulomatosis with polyangiitis and microscopic polyangiitis and focuses on the clinical and diagnostic value of ANCA detection in patients with connective tissue diseases, idiopathic interstitial pneumonia, autoimmune liver diseases, inflammatory bowel diseases, anti-glomerular basement membrane (GBM) disease, infections, malignancy, and during drug treatment. Current evidence suggests that in certain settings beyond systemic vasculitis, ANCA may have clinical, pathogenic and/or diagnostic relevance. Antigen-specific ANCA targeting proteinase-3 and myeloperoxidase should be tested by solid phase immunoassays in any patient with clinical features suggesting ANCA-associated vasculitis and in all patients with anti-GBM disease, idiopathic interstitial pneumonia, and infective endocarditis associated with nephritis, whereas in patients with other aforementioned disorders routine ANCA testing is not recommended. Among patients with autoimmune liver diseases or inflammatory bowel diseases, ANCA testing may be justified in patients with suspected autoimmune hepatitis type 1 who do not have conventional autoantibodies or in case of diagnostic uncertainty to discriminate ulcerative colitis from Crohn's disease. In these cases, ANCA should be tested by indirect immunofluorescence as the target antigens are not yet well characterized. Many questions concerning the optimal use of ANCA testing in patients without ANCA-associated vasculitis remain to be answered.

Inpatient Burden and Mortality of Goodpasture's Syndrome in the United States: Nationwide Inpatient Sample 2003-2014

Background: Goodpasture’s syndrome is a rare, life-threatening, small vessel vasculitis. Given its rarity, data on its inpatient burden and resource utilization are lacking. We conducted this study aiming to assess inpatient prevalence, mortality, and resource utilization of Goodpasture’s syndrome in the United States. Methods: The 2003–2014 National Inpatient Sample was used to identify patients with a principal diagnosis of Goodpasture’s syndrome. The inpatient prevalence, clinical characteristics, in-hospital treatment, end-organ failure, mortality, length of hospital stay, and hospitalization cost were studied. Multivariable logistic regression was performed to identify independent factors associated with in-hospital mortality. Results: A total of 964 patients were admitted in hospital with Goodpasture’s syndrome as the principal diagnosis, accounting for an overall inpatient prevalence of Goodpasture’s syndrome among hospitalized patients in the United States of 10.3 cases per 1,000,000 admissions. The mean age of patients was 54 ± 21 years, and 47% were female; 52% required renal replacement therapy, whereas 39% received plasmapheresis during hospitalization. Furthermore, 78% had end-organ failure, with renal failure and respiratory failure being the two most common end-organ failures. The in-hospital mortality rate was 7.7 per 100 admissions. The factors associated with increased in-hospital mortality were age older than 70 years, sepsis, the development of respiratory failure, circulatory failure, renal failure, and liver failure, whereas the factors associated with decreased in-hospital mortality were more recent year of hospitalization and the use of therapeutic plasmapheresis. The median length of hospital stay was 10 days. The median hospitalization cost was $75,831. Conclusion: The inpatient prevalence of Goodpasture’s syndrome in the United States is 10.3 cases per 1,000,000 admissions. Hospitalization of patients with Goodpasture’s syndrome was associated with high hospital inpatient utilization and costs.

Characteristics and Outcomes of Patients with Anti-Glomerular Basement Membrane Antibody Disease and Anti-Neutrophil Cytoplasmic Antibodies

Background:

It is unclear whether patients with Anti-Glomerular Basement Membrane (GBM) disease and Anti-Neutrophil Cytoplasmic Antibodies (ANCA), so called “Double-Positive” (DP), have a different clinical presentation and outcome compared to patients with anti-GBM antibody disease alone. This study describes the clinical and histologic characteristics as well as the patient and renal outcomes of DP patients at the University of Washington compared to patients with anti-GBM antibody disease alone.

Methods:

Adults admitted to the University of Washington and Harborview Medical Centers from 2000 to 2016 who had a kidney biopsy showing anti-GBM disease characterized by crescentic glomerulonephritis with strong linear staining of glomerular basement membranes for IgG by immunofluorescence were included. Subjects were classified into anti-GBM or DP based on serologic testing. Information on demographics, clinical presentation, biopsy findings, initial treatment, and rates of relapse and patient and renal survival were collected. Continuous and categorical variables were analyzed using the Mann-Whitney U and Fisher’s exact tests, respectively.

Results:

There were 6 anti-GBM and 7 DP patients. Two patients were lost to follow-up after one year. There was no significant difference in clinical presentation or outcomes between the two groups. Two DP patients had greater than 50% global glomerulosclerosis. All the subjects developed ESRD. Two DP patients had a relapse while off immunosuppression. Two patients in each group died within 5 years of diagnosis.

Conclusion:

Two DP patients in our cohort had a relapse within 5 years of diagnosis. Multicenter studies are needed to determine whether DP patients have a higher relapse rate and need prolonged immunosuppression.

A relapsing case of pulmonary-renal syndrome after a sequential rise in MPO-ANCA and anti-GBM antibodies

A 69-year-old woman who presented with severe renal dysfunction and diffuse alveolar hemorrhage was diagnosed with pulmonary-renal syndrome (PRS) based on the coexistence of serum myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCA) and anti-glomerular basement membrane (GBM) antibodies (Ab). Hemodialysis was started; plasma exchange and intravenous methylprednisolone pulse therapy were administered followed by oral prednisolone administration. Pulmonary hemorrhage decreased; however, renal dysfunction persisted. On maintenance hemodialysis and prednisolone therapy, MPO-ANCA and anti-GBM Ab became negative at 4 and 10 months, respectively; thereafter, they became positive again at 18 and 35 months, respectively. At 36 months, there was relapse of pulmonary hemorrhage. Plasma exchange and intravenous methylprednisolone pulse therapy were administered; pulmonary hemorrhage ceased, and both antibodies became negative. It is known that PRS cases that are double positive for ANCA and anti-GBM Ab occasionally relapse after remission, and, even though they are double positive at initial diagnosis, most relapses occur with reappearance or re-elevation of ANCA but with absence of anti-GBM-Ab. Therefore, this was a rare relapsing case that presented with double-positive serology. Further, our observation that the reappearance of ANCA preceded that of anti-GBM-Ab suggests that ANCA contribute to the reproduction of anti-GBM Ab.

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.

Double-positive with positive anti-glomerular basement membrane antibody and ANCA-positive disease in a patient with dermatomyositis

Approximately one in four patients (23.3%) with inflammatory myositis including dermatomyositis can require evaluation for acute kidney injury. The main cause of kidney injury is acute tubular necrosis from medications or myoglobinuria, though clinicians should be aware of a wide variety of possible aetiologies. We present the case of a 44-year-old woman with stable anti-Jo1 dermatomyositis, who presented with acute kidney injury. During her hospital course, she was diagnosed with double-positive disease characterised by circulating anti-glomerular basement membrane antibody and myeloperoxidase antineutrophil cytoplasmic antibody and renal biopsy revealing crescentic glomerulonephritis with linear staining of capillary wall for IgG.

Anti-neutrophil cytoplasmic antibody-associated glomerulonephritis with detection of myeloperoxidase and phospholipase A2 receptor in membranous nephropathy-lesions: report of two patients with microscopic polyangiitis

Background

Podocyte phospholipase A₂ receptor (PLA₂R) is a major target antigen in idiopathic adult membranous nephropathy (MN). Histological PLA₂R staining in the renal tissue has proven to be useful for the detection of idiopathic MN. However, glomerular PLA₂R deposits have also been recently observed in several patients with secondary MN, such as hepatitis B virus-associated, hepatitis C virus-associated, and neoplasm-associated MN. Certain inflammatory environments have been suggested to lead to abnormal expression of PLA₂R epitopes, with the resulting production of PLA₂R autoantibodies.

Case presentation

We report two patients diagnosed with anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis with MN-lesions, in whom ANCA titers for myeloperoxidase (MPO) were persistently positive. The first patient was a 52-years-old man who presented with interstitial pneumonitis. Microscopic hematuria and proteinuria were found when the interstitial pneumonitis became more severe. Renal biopsy findings yielded a diagnosis of ANCA-associated glomerulonephritis (mixed class) with MN-lesions. The second patient was a 63-years-old woman who had been treated for relapsing polychondritis. Her renal tissue showed evidence of focal ANCA-associated glomerulonephritis with MN-lesions. Interestingly, both MPO and PLA₂R were detected in the glomerular subepithelial deposits of both patients. Immunoglobulin G (IgG) 1 and IgG2 were positive in the glomeruli of patient 2, and all subclasses of IgGs were positive in patient 1.

Conclusion

The present cases suggest that ANCA-associated glomerulonephritis could expose PLA₂R, leading to the development of MN-lesions.

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.

Goodpasture Syndrome Diagnosed One Year And A Half after the Appearance of the First Symptoms (Case Report)

BACKGROUND:

Goodpasture syndrome was originally described as an association of alveolar haemorrhage and glomerulonephritis. It occurs when the immune system attacks and destroys healthy body tissue.

AIM:

We are presenting a patient with a clinical picture of pulmonary haemorrhage and glomerulonephritis, which is diagnosed by renal biopsy.

CASE PRESENTATION:

His illness began a year and a half before being diagnosed. In that period he had occasional exacerbations. He was received at our Clinic in extremely serious condition, and after stabilisation of his medical condition, there was made a biopsy of the kidney. The p-ANCA was 8.93 U/ml (neg < 3, poz > 5 U/ml). Histopathological diagnosis of biopsy of the kidney was: Glomerulonephritis extra capillaries focalis, segmentalis et globalis. Based on this he was diagnosed with Goodpasture syndrome. He received corticosteroid therapy and cyclophosphamide, with good response to treatment, and he is currently in a stable condition, receiving only corticosteroid therapy.

CONCLUSION:

Goodpasture syndrome is a severe illness caused by the formation of antibodies to the glomerular basement membrane and alveolus with consequential damage to renal and pulmonary function. With current therapy, long-term survival is more than 50%.

Systematic Review of Diffuse Alveolar Hemorrhage in Systemic Lupus Erythematosus: Focus on Outcome and Therapy

BACKGROUND

Diffuse alveolar hemorrhage (DAH) is an uncommon but potentially life-threatening manifestation of systemic lupus erythematosus (SLE) associated with high mortality. Although survival and its associated clinical, laboratory, and therapeutic features have been reported for case reports and series, they have not been systematically reviewed.

OBJECTIVES

The purpose of this systematic review was to assess survival of episodes of DAH in SLE over 3 decades and to categorize trends in therapies, commonly utilized to treat this disorder.

RESULTS

Overall, SLE patients survived 61% of 174 DAH episodes representing 140 patients. Episode survival was 67% in the time period from 2000 to 2013. Corticosteroids were nearly universally used therapeutically, and cyclophosphamide was used in 55%. Plasmapheresis was used in 31% and did not appear to be associated with survival.

CONCLUSIONS

Diffuse alveolar hemorrhage in SLE still carries a high risk of mortality; however, survival trends appear to demonstrate an increase from approximately 25% in the 1980s to 67% in the current decade. Increased use of cyclophosphamide appears to be associated with better survival, whereas plasmapheresis does not appear to influence outcome. Although these results need to be interpreted with caution because they are not derived from randomized controlled trials, we believe this represents the largest reported compilation of survival data in DAH associated with SLE.

Links between coagulation, inflammation, regeneration, and fibrosis in kidney pathology

Acute kidney injury (AKI) involves nephron injury leading to irreversible nephron loss, ie, chronic kidney disease (CKD). Both AKI and CKD are associated with distinct histological patterns of tissue injury, but kidney atrophy in CKD involves tissue remodeling with interstitial inflammation and scarring. No doubt, nephron atrophy, inflammation, fibrosis, and renal dysfunction are associated with each other, but their hierarchical relationships remain speculative. To better understand the pathophysiology, we provide an overview of the fundamental danger response programs that assure host survival upon traumatic injury from as early as the first multicellular organisms, ie, bleeding control by coagulation, infection control by inflammation, epithelial barrier restoration by re-epithelialization, and tissue stabilization by mesenchymal repair. Although these processes assure survival in the majority of the populations, their dysregulation causes kidney disease in a minority. We discuss how, in genetically heterogeneous population, genetic variants shift balances and modulate danger responses toward kidney disease. We further discuss how classic kidney disease entities develop from an insufficient or overshooting activation of these danger response programs. Finally, we discuss molecular pathways linking, for example, inflammation and regeneration or inflammation and fibrosis. Understanding the causative and hierarchical relationships and the molecular links between the danger response programs should help to identify molecular targets to modulate kidney injury and to improve outcomes for kidney disease patients.

Anti-glomerular basement membrane crescentic glomerulonephritis: A report from India and review of literature

Anti-glomerular basement membrane (anti-GBM) disease is an autoimmune disease that most commonly presents as rapidly progressive glomerulonephritis with or without pulmonary involvement. It is characterized by the presence of antibodies directed to antigenic targets within glomerular and alveolar basement membranes. This study was performed to evaluate the clinicopathological features and outcome in anti-GBM crescentic glomerulonephritis (CrGN) at a tertiary care center in North India over a period of 9 years (January 2004 to December 2012). A diagnosis of anti-GBM CrGN was made in the presence of >50% crescents, linear deposits of IgG along GBM, and raised serum anti-GBM antibody titer. Of 215 cases of CrGN diagnosed during this period, 11 had anti-GBM CrGN. Anti-GBM CrGN was found at all ages but was most common in the third to fifth decade with no gender predilection (mean age 48 +/- 15 years, 13–67 years). Patients presented with a mean serum creatinine of 10.2 +/- 5.3 mg/dl and sub-nephrotic proteinuria. Pulmonary involvement was present in two patients. Myeloperoxidase-antineutrophil cytoplasmic antibody was positive in two (2/11) elderly patients. Follow-up was available in four patients for a range of 30-270 (mean 99.5 ± 114.5) days, two remained dialysis dependent while two died due to uremia and sepsis. Our findings show that anti-GBM disease is a rare cause of CrGN in India, accounting for only 5% of patients. It usually presents as a renal-limited disease and is associated with a poor renal outcome.

Impact of anti-glomerular basement membrane antibodies and glomerular neutrophil activation on glomerulonephritis in experimental myeloperoxidase-antineutrophil cytoplasmic antibody vasculitis

BACKGROUND

Antineutrophil cytoplasmic antibody (ANCA) and neutrophil interactions play important roles in ANCA-associated vasculitis (AAV) pathogenesis. However, mechanisms underlying the pathogenesis of crescent formation in ANCA-associated vasculitis have not been completely elucidated. To ascertain the involvement of these interactions in necrotizing crescentic glomerulonephritis (NCGN), we used an AAV rat model and investigated the effects of the anti-myeloperoxidase (MPO) antibody (Ab) titer, tumor necrosis factor α (TNF-α), granulocyte colony-stimulating factor (G-CSF) and subnephritogenic anti-glomerular basement membrane (GBM) Abs, as proinflammatory stimuli.

METHODS

NCGN was induced in Wistar Kyoto rats by human MPO (hMPO) immunization. Renal function, pathology, and glomerular cytokine and chemokine expression were evaluated in hMPO-immunized rats with/without several co-treatments (TNF-α, G-CSF or subnephritogenic anti-GBM Abs). Rat neutrophils activation by IgG purified from rat serum in each group was examined in vitro.

RESULTS

The hMPO-immunized rats had significantly higher level of anti-hMPO Ab production. The induced anti-hMPO Abs cross-reacted with TNF-α- or G-CSF-primed rat neutrophils secreting TNF-α and interleukin-1β in vitro. The reactivity of anti-MPO Abs against rat MPO, crescent formation with neutrophil extracellular traps and glomerular-activated neutrophil infiltration in the rat model were significantly enhanced by subnephritogenic anti-GBM Ab but not by TNF-α or G-CSF administration. The model rats injected with the subnephritogenic anti-GBM Abs showed increased urinary albumin excretion and serum TNF-α, chemokine (C-X-C) ligand 1 (CXCL1) and CXCL2 levels. TNF-α, CXCL1, CXCL2 and CXCL8 increased in the glomeruli with significant amounts of crescent formation. In addition, in vitro activated neutrophils decreased CXC chemokine receptor 1 (CXCR1) and CXCR2 expressions.

CONCLUSIONS

The coexistence of subnephritogenic anti-GBM Abs leads to the inflammatory environment in glomeruli that is amplified by the interaction of ANCA and neutrophils. Development of NCGN in MPO-AAV may be necessary for not only the accumulation of neutrophils in glomeruli, but also the aberrant neutrophil activation on glomerulonephritis.

Conventional induction and maintenance treatment of Antineutrophil cytoplasmic antibodies-associated vasculitis - still of value for our patients?

INTRODUCTION

Antineutrophil cytoplasmic antibodies-associated vasculitis (AAV) is a group of autoimmune diseases characterized by the necrotizing inflammation of small vessels and associated with the antineutrophil cytoplasmic antibodies. Treatment of AAV can be divided into the induction phase aimed at achieving remission of the disease and the maintenance phase aimed at prevention of relapses. Long-term outcome of AAV dramatically improved with the introduction of cyclophosphamide. Recent clinical studies resulted in the reduction of the cumulative dose of cyclophosphamide and introduction of new treatment options, namely B-cell-depleting antibody rituximab, into both induction and maintenance treatment. This paper aims to evaluate the current role of the conventional induction and maintenance treatment in view of the gradually increasing use of rituximab.

AREAS COVERED

This paper provides an overview of the main clinical studies in induction and maintenance treatment of adult patients with AAV, treatment of relapses of AAV and shortly comments also on the treatment of refractory AAV, treatment of different subgroups of AAV (based on the age, renal function, clinical presentation and type of autoantibody), long-term outcome of patients with AAV, adverse events of treatment and treatment of end-stage renal disease in AAV.

EXPERT OPINION

Our analysis demonstrates that although the introduction of rituximab modified the approach to both the induction and maintenance treatment of AAV, more conventional induction and maintenance treatment with standard immunosuppressive drugs still retains its importance as we need more data on long-term efficacy and safety of biologic treatment, and also its cost-effectiveness still remains an open issue.

Pulmonary vasculitis

Pulmonary vasculitis encompasses inflammation in the pulmonary vasculature with involved vessels varying in caliber from large elastic arteries to capillaries. Small pulmonary capillaries are the vessels most commonly involved in vasculitis affecting the lung. The antineutrophil cytoplasmic antibody-associated vasculitides, which include granulomatosis with polyangiitis (formerly Wegener granulomatosis), microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome), are the small vessel vasculitides in which pulmonary vasculitis is most frequently observed and are the major focus of this review. Vasculitic involvement of the large pulmonary vessels as may occur in Behçet syndrome and Takayasu arteritis is also discussed.

An essential role of interleukin-17 receptor signaling in the development of autoimmune glomerulonephritis

In recent years, proinflammatory cytokines in the nephritic kidney appear to contribute to the pathogenesis of AGN. The complex inflammatory cytokine network that drives renal pathology is poorly understood. IL-17, the signature cytokine of Th17 cells, which promotes autoimmune pathology in a variety of settings, is beginning to be identified in acute and chronic kidney diseases as well. However, the role of IL-17-mediated renal damage in the nephritic kidney has not been elucidated. Here, with the use of a murine model of experimental AGN, we showed that IL-17RA signaling is critical for the development of renal pathology. Despite normal systemic autoantibody response and glomerular immune-complex deposition, IL-17RA(-/-) mice exhibit a diminished influx of inflammatory cells and kidney-specific expression of IL-17 target genes correlating with disease resistance in AGN. IL-17 enhanced the production of proinflammatory cytokines and chemokines from tECs. Finally, we were able to show that neutralization of IL-17A ameliorated renal pathology in WT mice following AGN. These results clearly demonstrated that IL-17RA signaling significantly contributes to renal tissue injury in experimental AGN and suggest that blocking IL-17RA may be a promising therapeutic strategy for the treatment of proliferative and crescentic glomerulonephritis.

Clinical consequence and significance of anti-neutrophil cytoplasmic antibody positivity in anti-glomerular basement membrane disease

Introduction: Patients with renopulmonary syndrome who have both anti-neutrophil cytoplasmic and anti-glomerular basement membrane antibodies have been described since 1989. Aim: The aim of the authors was to analyse the data of “double positive” patients diagnosed in their department, and compare these with previous studies. Method: During the last 16 years, 87 anti-neutrophil cytoplasmic antibody positive and 11 anti-glomerular basement membrane antobody positive patients were diagnosed. Four patients with anti-glomerular basement membrane antibodies (36%) had detectable anti-neutrophil cytoplasmic antibodies, 2 patients were positive for anti-myeloperoxidase and 2 patients for anti-proteinase 3. Results: In comparison with patients having anti-glomerular basement membrane antibodies, the double-positive patients were characterized by older age (median of 46 vs. 24 years), lack of male dominance (50% vs. 71%), more frequent presence of previous extrarenal symptoms (50% vs. 0%), and lower anti-glomerular basement membrane antibody levels (<100EU/ml: 100% vs. 29%). The double-positive patients had more favourable 1-year survival (100% vs. 71%), despite their older age and similar treatment regimen (immunosuppression 100% in both groups, plasmapheresis in 75% vs. 86%), but 1-year renal survival was not different (25% vs. 14%). Conclusions: In agreement with literature data, about one third of patients with anti-glomerular basement membrane antibodies had detectable anti-neutrophil cytoplasmic antibodies, and the coexistence of the two antibodies may have clinical consequences. Orv. Hetil., 154 (43), 1696–1701.