An Unusual Case of Anti-Glomerular Basement Membrane Disease and Phospholipase A2 Receptor-Associated Membranous Nephropathy After Exposure to Hydrocarbons.

We present a rare case of a patient with toluene exposure manifesting as anti-glomerular basement membrane (GBM) disease on a background of phospholipase A2 receptor (PLA2R)-associated membranous nephropathy. A 23-year-old man presented to the emergency department with hypertension, headache, hemoptysis, anemia, acute kidney injury, glomerular hematuria, and proteinuria. He endorsed repeated exposure to toluene-containing products while repairing dirt bikes. Serologies were positive for anti-GBM antibodies. Kidney biopsy showed crescentic glomerulonephritis with linear immunoglobulin G and granular PLA2R staining by immunofluorescence. He was initially treated with high-dose steroids, plasmapheresis, and hemodialysis for pulmonary-renal syndrome followed by oral cyclophosphamide and prednisone, which were discontinued after 3 months when follow-up biopsies confirmed little chance for renal recovery. He remained on dialysis 1 year later. This case exhibits a unique presentation of anti-GBM syndrome and underlying membranous nephropathy following repeated hydrocarbon exposure. Inhaled toxins promote recurrent localized inflammation, unmasking previously hidden epitopes. Early diagnosis and appropriate use of immunosuppressive and extracorporeal therapies are necessary to prevent morbidity and to improve survival in this rare condition.

Endopeptidase Cleavage of Anti-Glomerular Basement Membrane Antibodies in vivo in Severe Kidney Disease: An Open-Label Phase 2a Study.

BACKGROUND: The prognosis for kidney survival is poor in patients presenting with circulating anti-glomerular basement membrane (GBM) antibodies and severe kidney injury. It is unknown if treatment with an endopeptidase that cleaves circulating and kidney bound IgG can alter the prognosis. METHODS: An investigator-driven phase 2a one-arm study (EudraCT 2016-004082-39) was performed in 17 hospitals in five European countries. A single dose of 0.25 mg/kg of imlifidase was given to 15 adults with circulating anti-GBM antibodies and an eGFR <15 ml/min per 1.73m2. All patients received standard treatment with cyclophosphamide and corticosteroids, but plasma exchange only if autoantibodies rebounded. The primary outcomes were safety and dialysis independency at 6 months. RESULTS: At inclusion, ten patients were dialysis dependent and the other five had eGFR levels between 7 and 14 ml/min per 1.73m2. The median age was 61 years (range 19-77), six were women, and six were also positive for anti-neutrophil cytoplasmic antibodies. Then 6 hours after imlifidase infusion, all patients had anti-GBM antibodies levels below the reference range of a prespecified assay. At 6 months 67% (ten out of 15) were dialysis independent. This is significantly higher compared with 18% (nine out of 50) in a historical control cohort (P<0.001, Fisher's exact test). Eight serious adverse events (including one death) were reported, none assessed as probably or possibly related to the study drug. CONCLUSIONS: In this pilot study, the use of imlifidase was associated with a better outcome compared with earlier publications, without major safety issues, but the findings need to be confirmed in a randomized controlled trial.Clinical Trial registration number: EUDRACT 2016-004082-39 https://www.clinicaltrialsregister.eu/ctr-search/trial/2007-001377-28/results.

A unique case of anti-GBM disease with concomitant anti-PLA2R positivity.

BACKGROUND: Concomitant occurrence of anti-GBM disease and anti-PLA2R positive membranous nephropathy have been previously described. However, to the best of our knowledge, this is the first case report that documents the co-occurrence of the diseases proven by both serologic and histologic methods. CASE PRESENTATION: A 51-year-old woman presented to hospital with nausea, bilateral lower extremity edema, dyspnea, dark urine, and then anuria. Symptoms developed one month after an upper respiratory tract infection. Laboratory results showed acute kidney injury, and hypoalbuminemia. Immunologic examination revealed both anti-GBM and anti-PLA2R positivity. Kidney biopsy demonstrated the histological features of Goodpasture's disease and anti-PLA2R positive membranous nephropathy. Steroid, cyclophosphamide, and plasmapheresis were commenced. Despite the combined immunosuppressive, the patient remained on renal replacement therapy. CONCLUSIONS: Microbial kidney injury can trigger multiple autoimmune diseases. The simultaneous occurrence of anti-glomerular basement (anti-GBM) disease and membranous nephropathy is extremely rare. Delayed recognition leads to delayed treatment, causing worse renal and patient outcomes, as well as increased financial costs.

Laminin-521 is a Novel Target of Autoantibodies Associated with Lung Hemorrhage in Anti-GBM Disease.

BACKGROUND: Antiglomerular basement membrane (anti-GBM) disease is characterized by GN and often pulmonary hemorrhage, mediated by autoantibodies that typically recognize cryptic epitopes within α345(IV) collagen-a major component of the glomerular and alveolar basement membranes. Laminin-521 is another major GBM component and a proven target of pathogenic antibodies mediating GN in animal models. Whether laminin-521 is a target of autoimmunity in human anti-GBM disease is not yet known. METHODS: A retrospective study of circulating autoantibodies from 101 patients with anti-GBM/Goodpasture's disease and 85 controls used a solid-phase immunoassay to measure IgG binding to human recombinant laminin-521 with native-like structure and activity. RESULTS: Circulating IgG autoantibodies binding to laminin-521 were found in about one third of patients with anti-GBM antibody GN, but were not detected in healthy controls or in patients with other glomerular diseases. Autoreactivity toward laminin-521 was significantly more common in patients with anti-GBM GN and lung hemorrhage, compared with those with kidney-limited disease (51.5% versus 23.5%, P=0.005). Antilaminin-521 autoantibodies were predominantly of IgG1 and IgG4 subclasses and significantly associated with lung hemorrhage (P=0.005), hemoptysis (P=0.008), and smoking (P=0.01), although not with proteinuria or serum creatinine at diagnosis. CONCLUSIONS: Besides α345(IV) collagen, laminin-521 is another major autoantigen targeted in anti-GBM disease. Autoantibodies to laminin-521 may have the potential to promote lung injury in anti-GBM disease by increasing the total amount of IgG bound to the alveolar basement membranes.

PULMONARY HEMORRHAGE AND CRESCENTIC GLOMERULONEPHRITIS IN A PATIENT WITH SEROPOSITIVE ANTI-GLOMERULAR BASEMENT MEMBRANE DISEASE AND ANTI-NEUTROPHIL CYTOPLASMIC ANTIBODIES.

Anti-glomerular basement membrane (anti-GBM) disease is an acute and life-threatening systemic autoimmune disorder. The coexistence of circulating anti-neutrophil cytoplasmic antibodies (ANCA) and anti-GBM disease, the so-called double-positive disease (DPD), is exceptionally rare. We report a unique case of DPD manifesting as pulmonary-renal syndrome (PRS) in a 46-year-old woman who first presented with clinical and radiological suspicion of pneumonia. Chest computed tomography scan later revealed bilateral alveolar hemorrhage. Kidney biopsy showed necrotizing crescentic (100% glomeruli) glomerulonephritis. On immunofluorescence microscopy, glomeruli were global linear positive for IgG, confirming anti-GBM disease. Double positivity was detected for circulating anti-myeloperoxidase ANCA (p-ANCA) and anti-GBM antibodies. Acute renal failure evolved rapidly. Therapeutic plasma exchange (TPE) and hemodialysis (HD) were initiated early in combination with intravenous pulse corticosteroid therapy followed by oral methylprednisolone and cyclophosphamide. Pulmonary hemorrhage resolved, but renal function could not be preserved. The patient remains HD dependent. This case report highlights that pulmonary symptomatology may be the leading clinical presentation of PRS, with initially normal renal function at DPD onset. Early recognition and diagnosis are therefore crucial to timely clinical intervention. The role of prompt kidney biopsy and initiation of TPE and HD in PRS must not be underestimated.

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.

Comparison of the performance of a chemiluminescence assay and an ELISA for detection of anti-GBM antibodies.

Objective: Autoantibodies to the α3 chain noncollagen 1 domain of type IV collagen (α3(IV)NC1) are a serological hallmark in the diagnosis of anti-glomerular basement membrane (GBM) disease. The objective of our study was to compare the performance of anti-glomerular basement membrane (GBM) antibody detection by chemiluminescence immunoassay (CIA) and by enzyme-linked immunosorbent assays (ELISAs).Methods: Sera from outpatients who were suspected to have anti-GBM disease and 31 patients with biopsy-proven anti-GBM disease were collected. Thirty normal controls were also included. All samples were tested for anti-GBM antibodies by CIA and commercial ELISA. The anti-GBM antibody-positive samples were confirmed by a homemade ELISA coated with recombinant human α3(IV)NC1.Results: Compared with detection of anti-GBM antibodies with ELISA, detection of anti-GBM antibodies with CIA showed a positivity agreement of 70% and a negativity agreement of 98.6%. Among the 4 patients with different results, the anti-GBM antibody detection by CIA was in agreement with the homemade ELISA coated with recombinant human α3(IV)NC1 and the clinical diagnosis. In 31 patients with anti-GBM disease, good agreement was achieved in the detection of anti-GBM antibodies with CIA, commercial ELISA and the homemade ELISA (100%, 100%). The AUC for CIA and commercial ELISA was 0.987 and 0.966, respectively.Conclusions: The detection of anti-GBM antibodies with CIA demonstrated good sensitivity and specificity and was in good agreement with our homemade ELISA, which seems better than the commercial ELISA in suspected anti-GBM disease patients. The three assays performed in parallel in the diagnosis of anti-GBM disease patients.

Impact of ANCA-Associated Vasculitis on Outcomes of Hospitalizations for Goodpasture's Syndrome in the United States: Nationwide Inpatient Sample 2003-2014.

Background and objectives: Goodpasture's syndrome (GS) is a rare, life-threatening autoimmune disease. Although the coexistence of anti-neutrophil cytoplasmic antibody (ANCA) with Goodpasture's syndrome has been recognized, the impacts of ANCA vasculitis on mortality and resource utilization among patients with GS are unclear. Materials and Methods: We used the National Inpatient Sample to identify hospitalized patients with a principal diagnosis of GS from 2003 to 2014 in the database. The predictor of interest was the presence of ANCA-associated vasculitis. We tested the differences concerning in-hospital treatment and outcomes between GS patients with and without ANCA-associated vasculitis using logistic regression analysis with adjustment for other clinical characteristics. Results: A total of 964 patients were primarily admitted to hospital for GS. Of these, 84 (8.7%) had a concurrent diagnosis of ANCA-associated vasculitis. Hemoptysis was more prevalent in GS patients with ANCA-associated vasculitis. During hospitalization, GS patients with ANCA-associated required non-significantly more mechanical ventilation and non-invasive ventilation support, but non-significantly less renal replacement therapy and plasmapheresis than those with GS alone. There was no significant difference in in-hospital outcomes, including organ failure and mortality, between GS patients with and without ANCA-associated vasculitis. Conclusions: Our study demonstrated no significant differences between resource utilization and in-hospital mortality among hospitalized patients with coexistence of ANCA vasculitis and GS, compared to those with GS alone.

Activation of fibroblastic reticular cells in kidney lymph node during crescentic glomerulonephritis.

Crescentic glomerulonephritis is an inflammatory condition characterized by rapid deterioration of kidney function. Previous studies of crescentic glomerulonephritis have focused on immune activation in the kidney. However, the role of fibroblastic reticular cells, which reside in the stromal compartment of the kidney lymph node, has not been studied in this condition. We investigated the activation of kidney lymph node-resident fibroblastic reticular cells in nephrotoxic serum nephritis, a classic murine model of crescentic glomerulonephritis. We found that increased deposition of extracellular matrix fibers by fibroblastic reticular cells in the kidney lymph node was associated with the propagation of high endothelial venules, specialized blood vessels through which lymphocytes enter the lymph node, as well as with expansion of the lymphatic vasculature. The kidney lymph node also contained an expanding population of pro-inflammatory T cells. Removal of the kidney lymph node, depletion of fibroblastic reticular cells, and treatment with anti-podoplanin antibody each resulted in reduction of kidney injury. Our findings suggest that modulating the activity of fibroblastic reticular cells may be a novel therapeutic approach in crescentic glomerulonephritis.

Routinely used immunoassays do not detect circulating anti-GBM antibodies against native NC1 hexamer and EA epitope of the α3 chain of type IV collagen.

Detection of circulating anti-GBM antibodies has a key role for the diagnosis of Goodpasture syndrome but immunoassays using purified or recombinant alpha3(IV)NC1 as antigen do not recognize all anti-GBM antibodies. We show that anti-GBM antibodies directed against epitopes in their native conformation or cryptic epitopes are detected by indirect immunofluorescence.

Recurrence of Goodpasture syndrome without circulating anti-glomerular basement membrane antibodies after kidney transplant, a case report.

BACKGROUND: Goodpasture Syndrome (GS) is an autoimmune disease caused by the development of auto-antibodies against the Glomerular Basement Membrane (GBM). Linear deposit of immunoglobulins G on the GBM detected by immunofluorescence analysis of renal biopsies is a GS pathognomonic finding. GS is commonly monophasic and its incidence is 1.6 case per million per year. CASE PRESENTATION: This report describes and discusses the case of a 40-year-old woman who one year after allograft kidney transplant, presented with acute pulmonary and renal symptoms of GS, leading to acute graft dysfunction, without circulating anti-GBM antibody detection in laboratory assays. She received a living donor kidney transplant 4 years after the first diagnosis of GS without circulating anti-GBM antibodies, when considered in remission. CONCLUSIONS: In both episodes, the diagnosis of GS was based exclusively on the kidney biopsy that showed rapidly progressing glomerulonephritis with deposition of immunoglobulins G on the GBM. Although rare, the management of patients with GS without circulating anti-GBM antibodies is difficult due to the lack of standardized follow-up guidelines to reduce the risk of GS recurrence after kidney transplantation.

[Rapid progressive glomerulonephritis]. / Rapid-progressive Glomerulonephritis.

The rapid progressive glomerulonephritis is an emergency case. Renal function is rapidly lost within weeks or a few months (rarely within days) due to necrotizing extracapillary proliferative crescentic glomerulonephritis. Early diagnosis and treatment improve prognosis, as the best prognostic marker is creatinine when treatment is initiated. Three classes can be distinguished by immunofluorescence in histology. Firstly, there are no or only few immunoglobulins found (anti-neutrophil cytoplasmic antibody [ANCA]-associated vasculitis). Secondly, there is linear immunofluorescence due to antibodies against the glomerular basement membrane (anti-glomerular basement membrane [GBM] disease or Goodpasture syndrome); and thirdly, there is a granular pattern of immunoglobulin deposition (for example systemic lupus erythematosus [SLE], Schoenlein-Henoch purpura or cryoglobulinaemia). The immunosuppressive repertoire has improved (such as induction therapy in ANCA-associated vasculitis with lower total steroid dose, cyclophosphamide pulses or rituximab). New treatment approaches are on their way and the prognosis regarding life expectancy and renal function has improved. There are still challenging questions to answer like treatment duration and markers of recurrence.

Difficulties in Goodpasture's syndrome diagnosing.

The article analyzes the diagnosis and treatment of anti-GBM antibody disease (Goodpasture's syndrome) - a rare, severe progressive disease, associated with anti-glomerular basement membrane antibody-induced pulmonary hemorrhage and glomerulonephritis. The main problem of this pathology is late diagnosis, resulted in ineffective treatment. The article provides current information on the epidemiology, etiology and pathogenesis, diagnosis, and treatment of Goodpasture's syndrome, as well as clinical case of a patient with this rare disease.

The treatment of ANCA-associated rapidly-progressive glomerulonephritis and Goodpasture syndrome with therapeutic apheresis.

Therapeutic plasma aphresis (plasmapheresis) is one form of treatment that is frequently used in practice of Nephrology. Plasmapheresis is the most important part of the therapies for Goodpasture's syndrome and anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis which are causes of rapidly progressive glomerulonephritis. The reason why the effectiveness of plasmapheresis therapy cannot be clearly demonstrated in renal involvement in these diseases is that it does not appear to be possible to recruit an adequate number of patients and plasmapheresis is not effective in advanced disease if early treatment is not initiated.

Falsely positive anti-glomerular basement membrane antibodies in a patient with hantavirus induced acute kidney injury - a case report.

BACKGROUND: Hantavirus infection is an uncommon cause of acute renal failure with massive proteinuria. Serology tests to support a presumptive diagnosis usually take a few days. During the initial work-up, autoimmune causes including anti-glomerular basement membrane (GBM) glomerulonephritis need to be excluded, because these require urgent therapy. In this case the delay in serological testing caused a dilemma in treatment initiation. CASE PRESENTATION: An 18-year-old patient was admitted to the hospital with acute renal failure, erythrocyturia and massive proteinuria. Routine blood analysis showed leucocytosis (40,5 × 109/l) and a serum creatinine of 233 µmol/l. Infectious causes, e.g. leptospirosis or hantavirus infection, or an autoimmune disease, e.g., AAV or anti-GBM glomerulonephritis was the most feasible underlying diagnosis. Before hantavirus serology results were known, anti-GBM antibodies were positive. Treatment for anti-GBM glomerulonephritis was withheld, because of the absence of other signs and symptoms of the disease and slight improvement of renal function. The diagnosis of acute hantavirus infection was later on confirmed, by seroconversion of a follow-up serum sample. Without further intervention renal function recovered and anti-GBM antibodies disappeared. CONCLUSION: Hantavirus infection may induce anti-GBM antibodies, falsely suggestive of anti-GBM glomerulonephritis. Anti-GBM antibodies are supposed to be 100% specific. No earlier reports of false positive anti-GBM titers were reported. Nevertheless, the anti-GBM antibodies in this case were seen as an innocent bystander effect. Considering the need of urgent initiation of plasmapheresis and administration of immunosuppressants it may lead to diagnostic dilemmas with crucial therapeutic consequences. Knowledge of this anomaly when diagnosing acute renal failure, is very important.

Pulmonary vasculitis: diagnosis and treatment.

Pulmonary vasculitis is a group of rapidly progressing severe diseases characterized by vascular inflammation, destruction and necrosis of the pulmonary tissue. The pathological process in the lungs varies from diffuse alveolar hemorrhage to inflammation of the parenchyma, pleural effusion, thrombotic and thromboembolic complications. Depending on the size of the affected vessels, vasculites are divided into vasculites of large, medium and small vessels. Most frequently the lung is found in the small vessels vasculitis, including ANCA-associated vasculitis [granulomatosis with polyangiitis (GP), eosinophilic granulomatosis with polyangiitis (EGPA) and microscopic polyangiitis (MPA)] and the disease is glomerular basement membrane (goodpasture syndrome). Clinical examination of other systems and organs involved in the pathological process, including the skin and kidneys, as well as the detection of autoantibodies can improve approaches to early diagnosis and treatment of vasculitis. Treatment of life-threatening pulmonary bleeding and irreversible damage to organs, especially the kidneys, requires rapid diagnosis of these conditions. Vasculitis is a rare disease with lesions of many organs, and methods of their treatment, including biological, are rapidly developing, which requires the cooperation of doctors of various specialties and specialized centers to achieve better control of the disease.

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.

Plasmapheresis for the treatment of kidney diseases.

The purpose of this review is to examine the evidence supporting the application of plasma exchange in renal disease. Our review focuses on the following 6 most common renal indications for plasma exchange based on 2014 registry data from the Canadian Apheresis Group: (i) thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome; (ii) renal transplantation, (iii) anti-neutrophil cytoplasm antibodies-associated vasculitis, (iv) cryoglobulinemia, (v) focal segmental glomerulosclerosis, and (vi) Goodpasture syndrome. The rarity of these diseases and their rapid, often fatal course mean that randomized controlled studies of plasma exchange are rarely conducted. Although evidence from an adequately powered randomized controlled trial supports the use of plasma exchange to treat thrombotic thrombocytopenic purpura, the use of plasma exchange to treat other renal diseases is only supported by observational and mechanistic studies. Larger well-designed trials are needed to clarify the potential role of plasma exchange in renal disease. Growing international collaboration will improve the quality of future studies in this area.

Outcomes of patients with Goodpasture syndrome: A nationwide cohort-based study from the French Society of Hemapheresis.

The overall and renal outcomes of patients with Goodpasture syndrome (GS), a rare autoimmune disorder characterized by circulating anti-GBM antibodies and rapidly progressive glomerulonephritis and/or pulmonary hemorrhage, have mostly been reported in small-sized cohorts or by aggregating patients receiving a variety of therapies that include aggressive (i.e., combined plasma exchanges, corticosteroids, and cyclophosphamide) and less aggressive (i.e., either plasma exchanges or immunosuppressive drugs, or no treatment). To address the prognosis of GS patients with relatively homogeneous management including plasma exchanges, we conducted a multicenter retrospective study on GS patients included in the registry of the French Society of Hemapheresis. 122 patients were included (kidney alone (n = 28), lung alone (n = 5), or combined involvement (n = 89)). All 122 patients received plasma exchanges (median number of sessions: 13 [9-17]), either alone (n = 8) or associated with combined corticosteroids and oral or IV cyclophosphamide (n = 101) or with corticosteroids alone (n = 12) or cyclophosphamide alone (n = 2). One-year survival was 86.9%. 7/16 patients died from severe infection. In multivariate analyses (Cox's regression model), being aged <60 years, and number of plasma exchanges were correlated to overall survival. The use of alternative immunosuppressive drugs (because of refractory or relapsing GS) was correlated to mortality at one year. Superiority of oral cyclophosphamide compared to intravenous intake was close to significant. Using a logistic regression model, renal survival in patients alive at 1 year was only predicted by serum creatinine <500 µmol/L at presentation. This large series describes the predictive factors for overall and renal survival of GS patients treated by plasma exchanges. Interventional studies that compare oral and intravenous cyclophosphamide, as well as testing new immunosuppressive therapies, are warranted.

TH1 and TH17 cells promote crescent formation in experimental autoimmune glomerulonephritis.

Autoimmunity against the Goodpasture antigen α3IV-NC1 results in crescentic glomerulonephritis (GN). Both antibodies and T cells directed against α3IV-NC1 have been implicated in disease development and progression. Using the model of experimental autoimmune glomerulonephritis (EAG) in DBA/1 mice, we aimed to characterize the frequency and function of α3IV-NC1-specific CD4(+) T cells in the kidneys. DBA/1 mice repeatedly immunized with human α3IV-NC1 developed necrotizing/crescentic GN. Kidneys with crescentic GN contained CD4(+) cells responding to α3IV-NC1 with the production of IFN-γ or IL-17A, demonstrating the accumulation of both α3IV-NC1-specific TH1 and TH17 cells. To test the functional relevance of TH1 and TH17 cells, EAG was induced in DBA/1 mice deficient in IFN-γR, IL-17A or IL-23p19. Mice of all knockout groups mounted α3IV-NC1 IgG, developed nephrotic range proteinuria, and IgG deposition to the glomerular basement membranes at levels similar to immunized wild-type mice. However, all knockout groups showed significantly fewer glomerular crescents and attenuated tubulointerstitial damage. Our results suggest that both α3IV-NC1-specific TH1 and TH17 cells accumulate in the kidneys and are crucial for the development of necrotizing/crescentic GN.