ANCA-associated vasculitis and anti-GBM disease: the experience in China

Atypical Antiglomerular Basement Membrane Disease in a Pregnant Patient with Systemic Lupus Erythematosus

Antiglomerular basement membrane disease (anti-GBM) is an unusual cause of glomerulonephritis. Patients usually present with rapidly progressive glomerulonephritis with or without pulmonary hemorrhage. The diagnosis is based on linear deposits of IgG along the GBM and the presence of anti-GBM antibodies. However, cases with atypical anti-GBM disease in which an anti-GBM antibody was not detected have been reported. We report a 29-year-old pregnant woman with underlying systemic lupus erythematosus (SLE) who presented with severe glomerulonephritis due to atypical antiglomerular basement membrane disease. She was initially diagnosed with active lupus nephritis and her renal function gradually worsened after steroid treatment, so the pregnancy was terminated due to the high maternal and fetal risks. A kidney biopsy showed linear capillary wall staining with fibrous crescents without endocapillary proliferation. The anti-GBM antibody showed negative results two times, so she was diagnosed with atypical anti-GBM disease. Treatment began with intravenous pulse methylprednisolone and continued with mycophenolate mofetil and prednisolone. Due to the intolerability of side effects, the treatment regimen was subsequently changed to intravenous cyclophosphamide. Although she had a significant improvement in clinical edema, serum albumin, and hematuria, her renal function gradually decreased during the 12 months of treatment. A review of the literature showed that the atypical anti-GBM is less aggressive than the typical anti-GBM disease. However, several patients had persistent renal dysfunction and 20-30% of patients had progression to ERSD. To the best of our knowledge, this is the first case of atypical anti-GBM disease in pregnant patients with suspected SLE reported in the literature.

Epidemiology, Impact, and Management Strategies of Anti-Glomerular Basement Membrane Disease

Anti-glomerular basement membrane (anti-GBM) disease is a rare but serious autoimmune disease, which is characterized by the development of pathogenic antibodies to type IV collagen antigens in the glomerular and alveolar basement membranes. This results in rapidly progressive glomerulonephritis (GN), alveolar hemorrhage, or both. A variety of environmental factors can trigger the disease in genetically predisposed patients. Temporal associations with influenza, SARS-CoV-2 infection, and COVID-19 vaccination have been described although there is insufficient evidence to suggest causality. Anti-GBM disease accounts for approximately 20% of the cases of rapidly progressive GN cases secondary to crescentic GN, but is an uncommon cause of end-stage kidney disease. Early diagnosis by detection of circulating antibodies, increased awareness of atypical as well as complex clinical variants of the disease, and combined therapy with immunosuppression and plasma exchange has improved the prognosis of patients with this potentially fatal disease. Progress has been hampered by the rarity of anti-GBM disease, but new agents and therapeutic regimens are emerging.

Altered circulating CCR6+and CXCR3+ T cell subsets are associated with poor renal prognosis in MPO-ANCA-associated vasculitis

Background

Effector memory T cells are pivotal effectors of adaptive immunity with enhanced migration characteristics and are involved in the pathogenesis of ANCA-associated vasculitis (AAV). The diversity of effector memory T cells in chemokine receptor expression has been well studied in proteinase 3 (PR3)-AAV. However, few studies have been conducted in myeloperoxidase (MPO)-AAV. Here, we characterized chemokine receptor expression on effector memory T cells from patients with active MPO-AAV.

Methods

Clinical data from newly diagnosed MPO-AAV patients and healthy subjects were collected and analyzed. Human peripheral blood mononuclear cells (PBMCs) isolated from patients with active MPO-AAV were analyzed by flow cytometry. The production of effector memory T cell-related chemokines in serum was assessed by ELISA.

Results

We observed decreased percentages of CD4⁺ and CD8⁺ T cells in the peripheral blood, accompanied by a significant decrease in CCR6-expressing T cells but an increase in CXCR3⁺ T cells, in active MPO-AAV. Furthermore, the decrease in CCR6 and increase in CXCR3 expression were mainly limited to effector memory T cells. Consistent with this finding, the serum level of CCL20 was increased. In addition, a decreasing trend in the T_EM17 cell frequency, with concomitant increases in the frequencies of CD4⁺ T_EM1 and CD4⁺ T_EM17.1 cells, was observed when T cell functional subsets were defined by chemokine receptor expression. Moreover, the proportions of peripheral CD8⁺ T cells and CD4⁺ T_EM subsets were correlated with renal prognosis and inflammatory markers.

Conclusions

Our data indicate that dysregulated chemokine receptor expression on CD4⁺ and CD8⁺ effector memory T cells and aberrant distribution of functional CD4⁺ T cell subsets in patients with active MPO-AAV have critical roles related to kidney survival.

Demographic, clinical and laboratory characteristics of rapidly progressive glomerulonephritis in Turkey: Turkish Society of Nephrology-Glomerular Diseases (TSN-GOLD) Working Group

BACKGROUND

In our study, diagnostic and demographic characteristics of patients diagnosed with RPGN by biopsy, clinical and laboratory findings in our country were investigated.

METHODS

Data were obtained from the Turkish Society of Nephrology Glomerular Diseases (TSN-GOLD) Working Group database. Demographic characteristics, indications for biopsy, diagnosis of the glomerular diseases, comorbidities, laboratory and biopsy findings of all patients were recorded. According to their types, RPGN patients were classified as type 1 (anti-GBM related), type 2 (immuncomplex related) and type 3 (pauci-immune).

RESULTS

Of 3875 patients, 200 patients with RPGN (mean age 47.9 ± 16.7 years) were included in the study which constitutes 5.2% of the total glomerulonephritis database. Renal biopsy was performed in 147 (73.5%) patients due to nephritic syndrome. ANCA positivity was found in 121 (60.5%) patients. Type 1 RPGN was detected in 11 (5.5%), type 2 RPGN in 42 (21%) and type 3 RPGN in 147 (73.5%) patients. Median serum creatinine was 3.4 (1.9-5.7) mg/dl, glomerular filtration rate was 18 (10-37) ml/min/1.73m² and proteinuria 2100 (1229-3526) mg/day. The number of crescentic glomeruli ratio was ratio 52.7%. It was observed that urea and creatinine increased and calcium and hemoglobin decreased with increasing crescentic glomerular ratio.

CONCLUSIONS

Our data are generally compatible with the literature. Advanced chronic histopathological findings were prominent in the biopsy of 21 patients. Early biopsy should be performed to confirm the diagnosis of RPGN and to avoid unnecessary intensive immunosuppressive therapy. In addition to the treatments applied, detailed data, including patient and renal survival, are needed.

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.

Management of End-stage Renal Disease Associated with Systemic Rheumatic Diseases

The outcomes of rheumatic diseases (RDs) have improved over the past decades. However, a significant proportion of the patients still suffer from end-stage renal disease (ESRD) and have to bear the burden of hemodialysis. It is crucial to prevent patients with RDs from developing ESRD from viewpoints of medicine and medical economics. For those who already have ESRD, it is important to improve vial prognosis and quality of life through appropriate management of disease activity and comorbidities related to ESRD. Thus, rheumatologists and nephrologists need to recognize risk factors associated with progression to ESRD along with their appropriate management. Although the activity of most RDs tends to decrease after initiation of hemodialysis, disease activity may still increase, and recognizing how to appropriately use immunosuppressive agents even after the development of ESRD is crucial. The treatment of RDs needs extra attention as hydroxychloroquine requires more frequent monitoring for adverse drug reactions; therapeutic drug monitoring is necessary for mycophenolate mofetil, cyclosporine A, and tacrolimus; cyclophosphamide and azathioprine need dose adjustments; methotrexate and bucillamine are contraindicated in patients with ESRD; leflunomide and sulfasalazine do not require significant dose reduction and iguratimod should be carefully administered. The pharmacokinetics of biological agents such as rituximab or belimumab are not affected by ESRD, and dose adjustments are not necessary. Collaboration between rheumatologists and nephrologists is needed more than ever and is expected to produce a complementary effect and achieve better outcomes in clinical settings, although this cooperation has not always been conducted appropriately.

Clinicopathological features and prognostic analysis of 49 cases with crescentic glomerulonephritis

Rapidly progressive glomerulonephritis (RPGN), characterized by rapid kidney dysfunction caused by aggressive glomerulonephritis, is usually associated with crescentic glomerulonephritis (CrGN). In the present study, the data from patients with CrGN were retrospectively analyzed at a tertiary medical center in China with the aim of investigating the clinicopathological features and the association of the type of CrGN with the prognosis. The renal biopsies of 49 patients diagnosed with CrGN were obtained between December 2011 and July 2016. Of the 49 patients, 11 patients (22.45%) had type I CrGN, 19 (38.78%) had type II CrGN and 19 (38.78%) had type III CrGN. The majority of CrGN patients exhibited multiple-system involvement and 28 patients (57.14%) had kidney enlargement. Proportions of patients with acute kidney injury (AKI), acute kidney diseases without AKI, and chronic kidney disease were 28.57, 46.94 and 24.49%, respectively. Among the 3 types of CrGN, patients with type I CrGN tended to have a higher proportion of AKI with more cellular crescent formation, and higher serum creatinine and retinol binding protein. Circulating anti-GBM antibodies were present in all type I CrGN patients and anti-neutrophilic cytoplasmic autoantibodies were detected in 84.21% of patients with type III CrGN. Type III CrGN patients had a superior kidney survival, whereas type I CrGN patients had the worst kidney prognosis (P<0.001). There was no significant difference in overall patient survival among the 3 types of CrGN. CrGN remains the primary cause of critical illness in RPGN patients. There was much heterogeneity between the different subtypes of CrGN. Patients with type I tended to have an acute onset and had the poorest kidney survival.

The effect of pulse methylprednisolone induction therapy in Chinese patients with dialysis-dependent MPO-ANCA associated vasculitis

BACKGROUND

Pulse methylprednisolone (MP) was routinely used before commencing standard immunosuppressive therapy for induction of remission in patients with dialysis-dependent anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in spite of the paucity of evidence of benefit. The aim of this study was thus to determine whether the addition of pulse MP to standard induction immunosuppressive therapy in severe myeloperoxidase (MPO) -AAV patients who were on dialysis at onset is associated with an improvement in kidney recovery and patient survival. Furthermore, we analyzed the factors associated with restoration of kidney function and mortality in a single Chinese cohort.

METHODS

69 MPO-AAV patients who were on dialysis at the time of diagnosis were included in this study. The MP group (n = 30) received pulse MP (5-10 mg/kg/day) for 3 days before the standard immunosuppressive therapy. The Non-MP group (n = 39) had no MP pulses. The outcomes and adverse events between the two groups were compared. In addition, the predictive value of the clinical and histological parameters for kidney and patient survival was assessed using univariate and multivariate logistic regression analysis.

RESULT

There was no difference in patient survival, kidney recovery and the rates of adverse events between the two groups. A higher Birmingham Vasculitis Activity Score (BVAS) was shown to be a negative prognostic factor for kidney function restoration (p = 0.046, OR 0.811, 95% CI 0.660-0.997). BVAS was also demonstrated to be an independent predictor for both all-cause death (p = 0.007, OR 1.324, 95% CI 1.079-1.624) and therapy-related death (p = 0.003, OR 1.574, 95% CI 1.171-2.115). Patients' eGFR at the presentation of the disease was shown to be an independent predictor for therapy-related death (p = 0.027, OR 2.535, 95% CI 1.112-5.779).

CONCLUSIONS

This retrospective study of MPO-AAV patients who required dialysis at presentation in a single Chinese center suggests that the addition of pulse MP to standard immunosuppressive induction therapy for remission appears to confer no benefit in terms of improving patient outcomes. Further research is required to determine the role of pulse MP in severe MPO-AAV.

Risk HLA class II alleles and amino acid residues in myeloperoxidase-ANCA-associated vasculitis

A genome-wide association study (GWAS) indicated that myeloperoxidase-ANCA associated vasculitis (AAV) is associated with HLA-DQ. However, susceptibility alleles in these loci have been under-investigated. Here we genotyped 258 Chinese patients with myeloperoxidase-AAV and 597 healthy control individuals at HLA DRB1, DQA1, DQB1 and DPB1, and extracted the encoded amino acid sequences from the IMGT/HLA database. The replication cohort included 97 cases and 107 controls. T cell epitopes of myeloperoxidase were predicted and docked to the HLA molecules. We found DQA1∗0302 (odds ratio 2.34 (95% confidence interval 1.75-3.14)) and DQB1∗0303 (odds ratio 1.89 (1.45-2.48)) were risk alleles for myeloperoxidase-AAV. They are in overt linkage disequilibrium (r² 0.69) and the haplotype DQA1∗0302-DQB1∗0303 presents a significant risk (haplotype score 6.39) as well. Aspartate160 on the DQ α chain (odds ratio 2.06 (1.60-2.67)), encoded by DQA1∗0302, and isoleucine185 on the DQ β chain (odds ratio 1.73 (1.38-2.18)), encoded by DQB1∗0303, both located in the α2β2 domains, conferred significant risk for myeloperoxidase-AAV. Homologous modeling showed that DQα∗160D may confer susceptibility to myeloperoxidase-AAV by altering dimerization of the HLA molecules. Thus, more attention should be paid to the roles of amino acids in the α2β2 domains in addition to the α1β1 binding groove of HLA class II molecules.

[Antiglomerular basement disease in children: Literature review and therapeutic options]

Antiglomerular basement membrane glomerulonephritis is a rare autoimmune disease characterized by rapidly progressive glomerulonephritis that may be associated with pulmonary hemorrhage (Goodpasture syndrome). The disease is caused by autoantibodies (classically IgGs) directed against the α3 subunit of type IV collagen. This is a rare disease in the adult population and extremely rare in children, with a reported cumulative annual incidence at 1/10⁶ people/year. Among scarce reported pediatric cases (n=31), most are girls (M/F sex ratio, 1:4), and the mean age at diagnoses is 9.2±4.6 years. A medical diagnosis is an emergency and is based on the identification of specific antibodies in the serum, and pathognomonic linear fixation of IgGs along the glomerular basement membrane. Without appropriate treatment, the disease is generally fulminant, and patient and kidney survival is poor. Indeed, glomerular function strongly correlates with histological lesions. The current guidelines recommend the use of plasma exchanges and immunosuppressive drugs. For the past few years, alternative therapeutics such as specific anti-B-cell antibodies (rituximab) or specific extrarenal cleansing such as immunoadsorption have been successfully used in adults. Immunoadsorptions (IAs) can remove pathogenic IgGs from the circulation and do not require plasma infusions, contrary to plasma exchanges. In this review, we discuss the key points of antiglomerular basement membrane glomerulonephritis diagnosis and conventional or alternative therapeutics.

The Prevalence and Management of Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis in China

BACKGROUND

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) comprises microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA) and eosinophilic GPA (EGPA). Myeloperoxidase (MPO) and proteinase 3 (PR3) are the main antigens for ANCA. AAV is a common multisystem autoimmune disease and most of the studies on AAV have been conducted in Western countries. Nowadays in China many efforts are made to investigate this disease.

SUMMARY

This review highlights the progress in the prevalence, management and outcomes of AAV in Chinese patients. With respect to the prevalence of AAV, though there are no precise data, AAV is not rare in the Chinese population. In Chinese patients with AAV there is a striking preponderance of MPA, and MPO-ANCA is much more common than PR3-ANCA. Even in patients with GPA there is a predominance of MPO-ANCA over PR3-ANCA. Propylthiouracil-induced AAV and ANCA-negative pauci-immune glomerulonephritis are stated in this review as well. With respect to the management of AAV, glucocorticoids in combination with cyclophosphamide remain the mainstay of induction therapy. Besides, we describe predictors of different outcomes in Chinese patients, including mortality, relapse, treatment resistance and end-stage renal disease.

KEY MESSAGES

AAV is not rare in the Chinese population. The disease spectrum and subtypes of ANCA are different between patients with AAV in China and Western countries. The treatment strategy for AAV in China is in consistency with that in Western countries. Predictors of different clinical outcomes are provided.

FACTS FROM EAST AND WEST

Treatment options for AAV are shared between the East and West, with corticosteroid combined with cyclophosphamide being the standard regimen for inductive therapy and switching to azathioprine after remission. The major cause of death in treated patients is infection related to immunosuppressive therapy within the first year after diagnosis, and this rate might be higher in China than in Western countries. Western studies demonstrated the efficacy and safety of rituximab for induction of remission in cases with relatively mild disease and maintenance therapy, but this agent is rarely used in China.

The predictive value of kidney biopsy in renal vasculitis: a multicenter cohort study

The histopathologic classification of antineutrophil cytoplasmic antibody-associated vasculitis has been demonstrated to have prognostic value in small cohorts of patients with pauci-immune extracapillary glomerulonephritis. We aimed to validate this histologic subgrouping system in a large cohort of patients with renal vasculitis from 3 Spanish centers. The additional value of several histologic parameters for predicting renal outcome was investigated. A total of 151 biopsies of patients with renal vasculitis were reviewed and classified as follows: 41% crescentic, 24% mixed, 21% focal, and 14% sclerotic. The cumulative proportions of renal survival at 5 years were 83.2%, 81.2%, 60.5%, and 50.7% for the focal, mixed, crescentic, and sclerotic categories, respectively (P < .05). In the crescentic category, patients with less than 75% of glomeruli showing crescents had better survival at 1 and 5 years compared with those having greater than or equal to 75% of crescents (77.9% and 70.6% versus 51.3% and 45.6%; P = .02). When adjusted by renal function and other histologic parameters, the percentage of extracapillary proliferation and glomerulosclerosis remained as significant predictors for renal survival (hazard ratio, 1.03; 95% confidence interval, 1.01-1.05; P = .001, and hazard ratio, 1.03; 95% confidence interval, 1.01-1.05; P = .002, respectively). In conclusion, patients with pauci-immune crescentic glomerulonephritis experienced different outcomes depending on the percentage of crescents observed, so that extensive extracapillary proliferation was associated with the poorest renal survival. These findings validate the prognostic utility of the histologic classification scheme in antineutrophil cytoplasmic antibody positive and negative patients and suggest a subdivision of crescentic category (<75% and ≥75% of crescents) based on the different survival rates observed among these subgroups.

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.

Pathogenesis of glomerular haematuria

Haematuria was known as a benign hallmark of some glomerular diseases, but over the last decade, new evidences pointed its negative implications on kidney disease progression. Cytotoxic effects of oxidative stress induced by hemoglobin, heme, or iron released from red blood cells may account for the tubular injury observed in human biopsy specimens. However, the precise mechanisms responsible for haematuria remain unclear. The presence of red blood cells (RBCs) with irregular contours and shape in the urine indicates RBCs egression from the glomerular capillary into the urinary space. Therefore glomerular haematuria may be a marker of glomerular filtration barrier dysfunction or damage. In this review we describe some key issues regarding epidemiology and pathogenesis of haematuric diseases as well as their renal morphological findings.

ANCA serotype and histopathological classification for the prediction of renal outcome in ANCA-associated glomerulonephritis

BACKGROUND

The phenotype of renal involvement in anti-neutrophil cytoplasmic antibodies (ANCA) vasculitis has a major influence on survival, and histological subgrouping of diagnostic renal biopsies has been proposed to aid in the prediction of renal outcome. We aimed to validate this histological subgrouping and to investigate the additional value of ANCA serotype in the prediction of renal outcome.

METHODS

Data were retrospectively collected from the time of diagnosis by systematic review of medical records from 136 patients with renal biopsies recruited to cohorts from the UK and Spain, over 15 years. The end point, renal survival, was the composite of end-stage renal disease (ESRD) or death from any cause. The occurrence of ESRD, Stage 4 Kidney Disease Outcomes Quality Initiative-Chronic Kidney Disease, was assessed separately, in order to establish a severity index risk of chronic kidney disease.

RESULTS

Renal survival at 5 years was 96% in the focal, 86% in the crescentic, 81% in the mixed and 61% in the sclerotic subgroups (P = 0.03). Myeloperoxidase (MPO)-ANCA was associated with more severe disease when compared with PR3-ANCA, as demonstrated by a lower frequency of focal and higher frequency of sclerotic subgroups, by more advanced interstitial fibrotic change and by lower glomerular filtration rate at diagnosis and worse renal function at 1 and 2 years.

CONCLUSIONS

We have confirmed the predictive value for renal survival of the ANCA vasculitis histology classification in a multi-centre study. We found a worse renal outcome in patients with tubulointerstitial fibrosis and atrophy. MPO-ANCA positive patients had a worse renal prognosis due to more severe glomerular injury. These results contribute to patient stratification in renal vasculitis for therapeutic, epidemiological and basic research.

Diagnosis and classification of Goodpasture's disease (anti-GBM)

Goodpasture's disease or anti-glomerular basement membrane disease (anti-GBM-disease) is included among immune complex small vessel vasculitides. The definition of anti-GBM disease is a vasculitis affecting glomerular capillaries, pulmonary capillaries, or both, with GBM deposition of anti-GBM autoantibodies. The disease is a prototype of autoimmune disease, where the patients develop autoantibodies that bind to the basement membranes and activate the classical pathway of the complement system, which start a neutrophil dependent inflammation. The diagnosis of anti-GBM disease relies on the detection of anti-GBM antibodies in conjunction with glomerulonephritis and/or alveolitis. Overt clinical symptoms are most prominent in the glomeruli where the inflammation usually results in a severe rapidly progressive glomerulonephritis. Despite modern treatment less than one third of the patients survive with a preserved kidney function after 6 months follow-up. Frequencies vary from 0.5 to 1 cases per million inhabitants per year and there is a strong genetic linkage to HLA-DRB1(∗)1501 and DRB1(∗)1502. Essentially, anti-GBM disease is now a preferred term for what was earlier called Goodpasture's syndrome or Goodpasture's disease; anti-GBM disease is now classified as small vessel vasculitis caused by in situ immune complex formation; the diagnosis relies on the detection of anti-GBM in tissues or circulation in conjunction with alveolar or glomerular disease; therapy is effective only when detected at an early stage, making a high degree of awareness necessary to find these rare cases; 20-35% have anti-GBM and MPO-ANCA simultaneously, which necessitates testing for anti-GBM whenever acute test for ANCA is ordered in patients with renal disease.

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.

Antineutrophil cytoplasmic autoantibodies: how are they detected and what is their use for diagnosis, classification and follow-up?

Antineutrophil cytoplasmic antibodies (ANCA) are traditionally detected by an indirect immunofluorescence technique. According to the international consensus on ANCA testing, ANCA should also be tested by antigen-specific tests for myeloperoxidase-ANCA and proteinase 3-ANCA. The direct noncompetitive enzyme-linked immunosorbent assay (ELISA) used to be the method of choice. Nowadays, these assays are called "first-generation" assays. Second-generation tests (capture ELISA) or third-generation tests (anchor ELISA) are more sensitive and specific for ANCA testing. We postulate that ANCA as detected by these newer ANCA tests may replace the need to perform indirect immunofluorescence-based assays. For classification of patients, ANCA serotype seems more important than classifying patients according to their clinical subtype, since genetics, clinical manifestations and response to therapy are more related to ANCA serotype than to clinical subtype. Detection of ANCA to monitor disease activity is still a controversial issue. Treatment based on ANCA levels is at present only experimentally performed in those patients who are treated with B-cell depletion therapy with rituximab. Future studies are needed to establish whether this way of monitoring patients is warranted.

Epitope analysis of anti-myeloperoxidase antibodies in patients with ANCA-associated vasculitis

Objective

Increasing evidences have suggested the pathogenic role of anti-neutrophil cytoplasmic antibodies (ANCA) directing myeloperoxidase (MPO) in ANCA-associated vasculitis (AAV). The current study aimed to analyze the association between the linear epitopes of MPO-ANCA and clinicopathological features of patients with AAV.

Methods

Six recombinant linear fragments, covering the whole length amino acid sequence of a single chain of MPO, were produced from E.coli. Sera from 77 patients with AAV were collected at presentation. 13 out of the 77 patients had co-existence of serum anti-GBM antibodies. Ten patients also had sequential sera during follow up. The epitope specificities were detected by enzyme-linked immunosorbent assay using the recombinant fragments as solid phase ligands.

Results

Sera from 45 of the 77 (58.4%) patients with AAV showed a positive reaction to one or more linear fragments of the MPO chain. The Birmingham Vasculitis Activity Scores and the sera creatinine were significantly higher in patients with positive binding to the light chain fragment than that in patients without the binding. The epitopes recognized by MPO-ANCA from patients with co-existence of serum anti-GBM antibodies were mainly located in the N-terminus of the heavy chain. In 5 out of the 6 patients, whose sera in relapse recognize linear fragments, the reactivity to linear fragments in relapse was similar to that of initial onset.

Conclusion

The epitope specificities of MPO-ANCA were associated with disease activity and some clinicopathological features in patients with ANCA-associated vasculitis.

Serum BAFF and APRIL might be associated with disease activity and kidney damage in patients with anti-glomerular basement membrane disease

AIM

B cell activating factor belonging to the tumour necrosis factor family (BAFF) and a proliferation inducing ligand (APRIL) are two tumour necrosis factor (TNF)-like cytokines that were found to be elevated in many autoimmune diseases. Anti-glomerular basement membrane (GBM) disease is a typical severe autoimmune disease characterized by raised serum anti-GBM antibodies. In this study we aimed to detect the serum levels of BAFF and APRIL in patients with anti-GBM disease, and their clinical significance was further analyzed.

METHODS

Forty-seven patients with anti-GBM disease were enrolled in this study. Forty-eight healthy individuals were used as normal controls. The levels of serum BAFF and APRIL were assessed using commercially available enzyme linked immunosorbent assay kits. The association between the levels of serum BAFF and APRIL, and the clinical and pathological parameters were further evaluated.

RESULTS

The serum levels of BAFF and APRIL in patients with anti-GBM disease were significantly higher than that in normal controls (12.3 ± 14.1 ng/mL vs. 0.9 ± 0.3 ng/mL, P < 0.001; 19.1 ± 22.9 ng/mL vs. 1.6 ± 4.6 ng/mL, P < 0.001), respectively. The levels of serum APRIL were correlated with the titres of anti-GBM antibodies (r = 0.347, P = 0.041), and the levels of serum BAFF were associated with the percentage of glomeruli with crescents (r = 0.482, P = 0.015) in patients with anti-GBM disease.

CONCLUSION

The levels of serum BAFF and APRIL were raised in patients with anti-GBM disease and might be associated with disease activity and kidney damage.

Predictors for outcomes in patients with severe ANCA-associated glomerulonephritis who were dialysis-dependent at presentation: a study of 89 cases in a single Chinese center

OBJECTIVE

Anti-neutrophilcytoplasmic autoantibody (ANCA)-associated vasculitis may cause rapid deterioration of renal function, resulting in high prevalence of end-stage renal disease and mortality. The current study investigated factors associated with restoration of renal function and early mortality in patients with severe ANCA-associated glomerulonephritis, i.e. dialysis-dependent at presentation, in a single Chinese cohort.

METHODS

Eighty-nine Chinese patients with ANCA-associated glomerulonephritis who were on dialysis at the time of diagnosis were included in this study. All these patients received immunosuppressive therapy plus intravenous methylprednisolone, plasma exchange, or both. The predictive value of the clinical and histological parameters for renal and patient outcome was analyzed.

RESULT

On the sixth month, 25 (28.1%) patients achieved dialysis independence, 45 (50.6%) patients progressed to end stage renal disease, and 19 (21.3%) patients died. Nine out of the 19 deaths were therapy-related. Factors independently associated with renal function restoration were percentages of normal glomeruli (P<0.05), extent of tubular atrophy (P<0.05) and extent of interstitial fibrosis (P<0.05) in the renal specimens. Age and pulmonary hemorrhage were independently associated with all-cause death (P=0.003 and P=0.007, respectively) and therapy-related death (P=0.037 and P=0.043, respectively).

CONCLUSIONS

Among patients with severe ANCA-associated glomerulonephritis who were dialysis-dependent at presentation, those with a higher percentage of normal glomeruli and less extent of tubular atrophy/interstitial fibrosis have more chance of restoration of renal function. Increased risk for all-cause death and therapy-related death appears to be older age and pulmonary hemorrhage.

Classification of antineutrophil cytoplasmic autoantibody vasculitides: the role of antineutrophil cytoplasmic autoantibody specificity for myeloperoxidase or proteinase 3 in disease recognition and prognosis

OBJECTIVE

To compare the usefulness of 3 currently used classification systems in predicting the outcomes of treatment resistance, disease relapse, end-stage renal disease (ESRD), and death in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

METHODS

Three classification systems were applied to 502 patients with biopsy-proven AAV: 1) the Chapel Hill Consensus Conference (CHCC) definition with categories for granulomatosis with polyangiitis (GPA) (Wegener's), microscopic polyangiitis (MPA), and kidney-limited disease; 2) the European Medicines Agency (EMA) system with categories for GPA and MPA; and 3) classification based on ANCA with specificity for myeloperoxidase (MPO ANCA) versus ANCA with specificity for proteinase 3 (PR3 ANCA). Outcomes included treatment resistance, relapse, ESRD, and death. Proportional hazards models were compared between systems using an information-theoretic approach to rank models by predictive fit. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) and P values are reported.

RESULTS

ANCA specificity was predictive of relapse, with PR3 ANCA-positive patients almost twice as likely to relapse as those with MPO ANCA (HR 1.89 [95% CI 1.33-2.69], P = 0.0004), and ANCA specificity had the best predictive model fit (model rank 1) compared to the CHCC and EMA systems. The CHCC and EMA systems did not predict relapse. By ANCA specificity, categories of GPA, MPA, and kidney-limited disease did not distinguish differences in probability of relapse-free survival. None of the systems predicted treatment resistance, ESRD, or death.

CONCLUSION

ANCA specificity independently predicts relapse among patients with AAV with renal disease. Classification and diagnostic systems that incorporate ANCA specificity, such as PR3 ANCA-positive MPA and MPO ANCA-positive MPA, provide a more useful tool than the clinical pathologic category alone for predicting relapse.

Anti-glomerular basement membrane antibody disease is an uncommon cause of end-stage renal disease

There are few reports regarding outcomes of anti-glomerular basement membrane (GBM) disease in patients who underwent renal replacement therapy. To help define this we studied all patients with anti-GBM disease who started renal replacement therapy for end-stage renal disease (ESRD) in Australia and New Zealand (ANZDATA Registry) between 1963 and 2010 encompassing 449 individuals (0.8 percent of all ESRD patients). The median survival on dialysis was 5.93 years with death predicted by older age and a history of pulmonary hemorrhage. Thirteen patients recovered renal function, although 10 subsequently experienced renal death after a median period of 1.05 years. Of the 224 patients who received their first renal allograft, the 10-year median patient and renal allograft survival rates were 86% and 63%, respectively. Six patients experienced anti-GBM disease recurrence in their allograft, which led to graft failure in two. Using multivariable Cox regression analysis, patients with anti-GBM disease had comparable survival on dialysis or following renal transplantation (hazard ratios of 0.86 and 1.03, respectively) compared to those with ESRD due to other causes. Also, renal allograft survival (hazard ratio of 1.03) was not altered compared to other diseases requiring a renal transplant. Thus, anti-GBM disease was an uncommon cause of ESRD, and not associated with altered risks of dialysis, transplant or first renal allograft survival. Death on dialysis was predicted by older age and a history of pulmonary hemorrhage.

Re-evaluation of the histopathologic classification of ANCA-associated glomerulonephritis: a study of 121 patients in a single center

BACKGROUND

The recently published histopathologic classification of antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis might greatly aid in the prognostication of patients at the time of diagnosis. This study aims to re-evaluate the new classification for its prognostic capacity in an independent Chinese series.

METHODS

One hundred and twenty-one consecutive patients with ANCA-associated glomerulonephritis, diagnosed in our center from 1997 to 2010, were included in this retrospective study. The renal specimens were reviewed according to the proposed histopathologic classification. The predictive value of the classification for renal outcome and renal response to treatment was analyzed.

RESULTS

Thirty-three (27.3%), 24 (19.8%), 53 (43.8%) and 11 (9.1%) patients were classified as focal, mixed, crescentic and sclerotic ANCA-associated glomerulonephritis, respectively. The renal biopsy categories correlated with initial serum creatinine and the renal response to treatment (P < 0.001, P < 0.01, respectively). The probability of progressing to end-stage renal disease (ESRD) increased with ascending categories of focal, mixed, crescentic and sclerotic glomerulonephritis (P < 0.01). The patients with focal, mixed and crescentic ANCA-associated glomerulonephritis were all at decreased risk for developing ESRD compared with the patients with in the sclerotic category (P < 0.05).

CONCLUSIONS

The proposed classification system was re-evaluated for the first time in a relatively large and independent series of patients. This system reflects the severity of the initial renal impairment and can predict, at least to some extent, the renal response to treatment. More importantly, it can independently predict renal outcome, in particular development of ESRD.