Wegener's Granulomatosis Research Articles

Immunoadsorption and Plasma Exchange are Comparable in Anti-Neutrophil Cytoplasmic Antibodies or Anti-Glomerular Basement Membrane Removal Kinetics

IntroductionApheresis allows the fast removal of auto-antibodies in anti-glomerular basement membrane (GBM) disease, and in severe ANCA-associated vasculitis. The CINEVAS study tested whether immunoadsorption (IA) allowed a faster removal of ANCA and/or anti-GBM antibodies than plasma exchanges (PEx). MethodsCINEVAS was a prospective multicenter study comparing IA to PEx in consecutive patients with ANCA and/or anti-GBM vasculitides. The primary objective was the reduction rate in auto-antibody titers between the beginning of the first and the end of the seventh apheresis session. Secondary objectives were: number of sessions needed to obtain desired reduction rates; reduction rates of total immunoglobulin (Ig) levels; tolerance of sessions; and patients’ outcome. ResultsThe results of 38 patients (16 treated with IA and 22 with PEx), and 43 auto-antibodies, were analyzed. There was no difference in the reduction rates in auto-antibody titers over 7 sessions between IA and PEx (respectively 98% vs 96%, p=0.39). The numbers of sessions needed to obtain undetectable auto-antibodies, or 50%, 75% or 90% reductions, did not differ between techniques. Greater reduction rates of auto-antibodies were observed when plasma was separated by filtration compared to centrifugation, with IA and PEx. IA allowed a greater reduction in total IgG levels, and better preservation of total IgA and IgM levels than PEx. PEx sessions required higher volumes of plasma, IA sessions higher volumes of citrate; IA sessions were longer. ConclusionsImmunoadsorption and plasma exchange were comparable in ANCA or anti-GBM removal kinetics, despite a faster reduction in total IgG with IA.

Co-existence of ANCA–associated vasculitides with immune-mediated diseases: a single-center observational study

BackgroundAntineutrophil cytoplasmic antibody-associated vasculitides (AAV) is a group of systemic necrotizing small vessel autoimmune diseases, with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) being the two most common. The co-existence of AAV with different immune-mediated diseases (autoimmune disesases - AID) might affect the clinical presentation of the primary disease. The purpose of the study was to assess the co-existence of AAV with AID and to investigate whether it affects the characteristics and the course of AAV.MethodsA retrospective single-center study was performed to identify patients with a diagnosis of MPA or GPA and concomitant AID, and to investigate their clinical features and characteristics. The group consisted of consecutive unselected AAV patients treated at a large university-based hospital, since 1988 with follow-up until 2022.ResultsAmong 284 patients diagnosed either with GPA (232) or MPA (52), 40 (14,1%) had co-existing AIDs. The most frequent were: Hashimoto thyroiditis (16 cases), rheumatoid arthritis (8 cases), followed by psoriasis (6 cases), pernicious anemia (3 cases), and alopecia (3 cases). Patients with autoimmune comorbidities had a significantly longer time between the onset of symptoms and the diagnosis (26 vs. 11 months, p < 0.001). Laryngeal involvement (20.0% vs. 9.0%, p = 0,05), peripheral nervous system disorders (35.0% vs. 13.9%, p < 0.001), and neoplasms (20.0% vs. 8.6%, p = 0,044) were more common in patients with AID comorbidities, compared to subjects without AID. In contrast, renal involvement (45.0% vs. 70.9%, p = 0.001) and nodular lung lesions (27.5% vs. 47.5%, p = 0.044) were significantly less frequent in patients with co-morbidities. Following EUVAS criteria, patients with autoimmune co-morbidities had a generalized form of the disease without organ involvement (52.5% vs. 27.2%, p = 0.007), while the others had a higher percentage of generalized form with organ involvement (38.3% vs. 20.0%, p = 0.007).ConclusionsThe coexistence of AAV with different autoimmune diseases is not common, but it might affect the clinical course of the disease. Polyautoimmunity prolonged the time to diagnosis, but the AAV course seemed to be milder. Particular attention should be paid to the increased risk of cancer in these patients. It also seems reasonable that AAV patients should receive a serological screening to exclude the development of overlapping diseases.

Application of Diffusion Kurtosis Imaging and Blood Oxygen Level-Dependent Magnetic Resonance Imaging in Kidney Injury Associated with ANCA-Associated Vasculitis.

Functional magnetic resonance imaging (fMRI) has been applied to assess the microstructure of the kidney. However, it is not clear whether fMRI could be used in the field of kidney injury in patients with Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study included 20 patients with AAV. Diffusion kurtosis imaging (DKI) and blood oxygen level-dependent (BOLD) scanning of the kidneys were performed in AAV patients and healthy controls. The mean kurtosis (MK), mean diffusivity (MD), and fractional anisotropy (FA) parameters of DKI, the R2* parameter of BOLD, and clinical data were further analyzed. In AAV patients, the cortex exhibited lower MD but higher R2* values compared to the healthy controls. Medullary MK values were elevated in AAV patients. Renal medullary MK values showed a positive correlation with serum creatinine levels and negative correlations with hemoglobin levels and estimated glomerular filtration rate. To assess renal injury in AAV patients, AUC values for MK, MD, FA, and R2* in the cortex were 0.66, 0.67, 0.57, and 0.55, respectively, and those in the medulla were 0.81, 0.77, 0.61, and 0.53, respectively. Significant differences in DKI and BOLD MRI parameters were observed between AAV patients with kidney injuries and the healthy controls. The medullary MK value in DKI may be a noninvasive marker for assessing the severity of kidney injury in AAV patients.

Classification Criteria for ANCA Associated Vasculitis - Ready for Prime Time?

This review aims to summarize the evolution and recent developments in the classification of ANCA associated vasculitis (AAV) and to summarize evaluations of the 2022 ACR/EULAR classification criteria of AAV in several cohorts. The classification of AAV has been a field of controversy for some time. The parallel existence of classification criteria and disease definitions produced some overlap in classification, leading to challenges when comparing different cohorts. The 2022 ACR/EULAR classification criteria derived from the largest study ever conducted in vasculitis account for significant changes in vasculitis classification with the integration of ANCA and modern imaging. These criteria show good performance compared to previous ones but also raise questions as ANCA serotypes have substantial impact on classification. In addition, there are some discrepancies with earlier agreed histopathological features of AAV disease phenotypes. During the last 35years, several sets of classification criteria have evolved to facilitate epidemiologic studies and clinical trials in AAV. While some of these criteria have been in use for many years, they were criticized due to either not using ANCA or not integrating surrogate markers for vasculitis but also due to overlapping when used in parallel. The long-awaited new ACR/EULAR criteria for AAV were published in 2022 and are the result of a large international study, introducing for the first time ANCA and modern imaging in the classification of AAV. Though the criteria show good performance, they bring several other challenges with practical application.

Novel Therapies for ANCA-associated Vasculitis: Apilimod Ameliorated Endothelial Cells Injury through TLR4/NF-κB Pathway and NLRP3 Inflammasome.

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is a rapidly progressive form of glomerulonephritis for which effective therapeutic drugs are currently lacking, and its underlying mechanism remains unclear. This study aimed to investigate new treatment options for AAV through a combination of bioinformatics analysis and cell molecular experiments. The research utilized integrated bioinformatics analysis to identify genes with differential expression, conduct enrichment analysis, and pinpoint hub genes associated with AAV. Potential therapeutic compounds for AAV were identified using Connectivity Map and molecular docking techniques. In vitro experiments were then carried out to examine the impact and mechanism of apilimod on endothelial cell injury induced by MPO-ANCA-positive IgG. The findings revealed a set of 374 common genes from differentially expressed genes and key modules of WGCNA, which were notably enriched in immune and inflammatory response processes. A proteinprotein interaction network was established, leading to the identification of 10 hub genes, including TYROBP, PTPRC, ITGAM, KIF20A, CD86, CCL20, GAD1, LILRB2, CD8A, and COL5A2. Analysis from Connectivity Map and molecular docking suggested that apilimod could serve as a potential therapeutic cytokine inhibitor for ANCA-GN based on the hub genes. In vitro experiments demonstrated that apilimod could mitigate tight junction disruption, endothelial cell permeability, LDH release, and endothelial activation induced by MPO-ANCA-positive IgG. Additionally, apilimod treatment led to a significant reduction in the expression of proteins involved in the TLR4/NF-κB and NLRP3 inflammasome-mediated pyroptosis pathways. This study sheds light on the potential pathogenesis of AAV and highlights the protective role of apilimod in mitigating MPO-ANCA-IgG-induced vascular endothelial cell injury by modulating the TLR4/ NF-kB and NLRP3 inflammasome-mediated pyroptosis pathway. These findings suggest that apilimod may hold promise as a treatment for AAV and warrant further investigation.

Glucocorticoid Minimization in Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis: An International Survey of Clinicians

Rationale & ObjectiveResearch in anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) has focused on reducing treatment toxicities, notably through reduction of exposure to glucocorticoids. Glucocorticoid-sparing therapies such as avacopan are not widely available in many countries and patients are exposed to high glucocorticoid doses. There is little data concerning what clinicians would accept as the lowest glucocorticoid dosing that could be used in induction therapy for AAV. Study DesignInternational, online survey Setting & ParticipantsClinicians in various countries, with experience in managing vasculitis. Exposure and OutcomesSurvey questions to gauge interest and preferences in studying an induction of remission regimen for severe AAV using only 2 or 4 weeks of glucocorticoids, without avacopan. Data collected included general opinions about standard of care for induction agents, glucocorticoids and avacopan. Respondents were presented with three candidate trial designs, two of which proposed a combination of cyclophosphamide and rituximab induction. Analytical ApproachUsing a 10-point Likert scale, respondents ranked each candidate trial on its usefulness in demonstrating whether a minimal glucocorticoid regimen will be safe and effective, and their willingness to randomize into the trial. ResultsThere were 210 respondents to the survey. The candidate trials were rated moderate-to-high for usefulness to demonstrate safety and efficacy (scores 6-7/10), and moderate (scores 5-6/10) for willingness to randomize. Four weeks glucocorticoid duration was preferred to 2 weeks, and combination cyclophosphamide-rituximab with 4 weeks glucocorticoids was the most preferred design. 42% of respondents felt avacopan had to be incorporated into a minimal GC trial design to want to recruit patients. LimitationsRepresentativeness of survey sample and generalisability of findings. ConclusionsCombination cyclophosphamide-rituximab may be the ideal way of studying minimal glucocorticoid use in severe AAV. Given its increasing uptake, incorporating avacopan into a potential trial design would be important.

Diagnostic accuracy of ANCA serology in ANCA-associated vasculitis with renal involvement.

Pauci-immune glomerulonephritis (GN) due to antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a common cause of crescentic GN. Despite advances in treatment, rates of mortality and progression to end-stage kidney disease remain high. Renal involvement is diagnosed by histological examination of kidney tissue. Serum ANCAs play a significant role in AAV; however, the value of serum ANCA quantification to predict renal involvement is not well-established. We aimed to evaluate the diagnostic accuracy of serum ANCA titres in diagnosing AAV with renal involvement. We conducted a retrospective study of consecutive native kidney biopsies reported at our centre from 2016 to 2021. We included all adults who had both a kidney biopsy and ANCA serology. ANCA serology was tested using indirect immunofluorescence with reporting of titres. Antibodies to proteinase 3 and myeloperoxidase were measured using a chemiluminescent immunoassay. Eight hundred and forty-eight native kidney biopsies were reported during the study period. Five hundred and seven cases were included. The biopsy prevalence of pauci-immune GN in paired samples was 41/507 (8.1%). Most of the cohort had haematuria (66.6%), proteinuria (93.4%) and/or acute kidney injury (65.0%). A positive ANCA at any titre demonstrated a sensitivity of 97.6% and a specificity of 71.2% for a diagnosis of pauci-immune GN. The area under the curve for the receiver operator characteristic was 0.93 (95% confidence interval [CI]: 0.89-0.97). A cutoff ANCA titre of 1:160 provided the optimum balance between a sensitivity of 75.6% (95% CI: 59.7%-87.6%) and a specificity of 94.0% (95% CI: 91.6%-96.0%). ANCA titres are highly predictive of pauci-immune GN in the appropriate context. While serum ANCA quantitation may not replace renal biopsy, reporting will assist in the decision to start treatment early for patients with organ or life-threatening disease.

Performance of clinical and histological prognostic scores for kidney survival in ANCA-associated vasculitis.

Integrating clinical and histological parameters into prognostic scores may enhance the prediction of progression to kidney failure in anti-neutrophil cytoplasm antibodies-associated vasculitis (AAV). This study aimed to evaluate the prognostic performance of histological classifications and scoring systems for kidney survival in AAV. This retrospective cohort study included 101 AAV patients with kidney involvement diagnosed by biopsy and followed for ≥12 months. The main outcome was the time to kidney failure. The prognostic performance of each histological and prognostic score was evaluated using Harrell's C statistic and Akaike's Information Criteria. Among the 101 patients, 37 progressed to kidney failure over a median follow-up of 75 months (IQR 39-123). The Harrell's C statistic was 0.702 (0.620-0.784), 0.606 (0.473-0.738), 0.801 (0.736-0.867), 0.782 (0.706-0.858), and 0.817 (0.749-0.885) for the EUVAS/Berden classification, Mayo Clinic Chronicity Score, Percentage of ANCA Crescentic Score (PACS), ANCA renal risk score (ARRS), and the improved ANCA kidney risk score (AKRiS), respectively. The AKRiS best discriminated the risk of kidney failure progression among subgroups. The AKRiS performance decreased with longer follow-up intervals. Adding the peak estimated glomerular filtration rate attained post-therapy improved the AKRiS performance at all follow-up intervals. Kidney relapses precipitated kidney failure in 71% of cases that progressed after the first year of follow-up. The novel AKRiS enhances the prediction of kidney failure in AAV with kidney involvement. As the prognostic yield of AKRiS decreases over time, a second calculation of AKRiS, including post-therapy kidney function, may improve its long-term performance.

Treatment goals in ANCA-associated vasculitis: defining success in a new era

Treatment goals in ANCA-associated vasculitis: defining success in a new era

Evaluating Single-Nucleotide Polymorphisms in Inflammasome Proteins and Serum Levels of IL-18 and IL-1β in Kidney Interstitial Damage in Anti-Neutrophilic Cytoplasmic Antibody-Associated Vasculitis.

The inflammasome regulates the innate inflammatory response and is involved in autoimmune diseases. In this study, we explored the levels of IL-18 and IL-1β in serum and urine and the influence of various single-nucleotide polymorphisms (SNPs) on kidney lesions at diagnosis in patients with ANCA-associated vasculitis (AAV) and their clinical outcomes. Ninety-two patients with renal AAV were recruited, and blood and urine were collected at diagnosis. Serum and urine cytokine levels were measured by ELISA. DNA was extracted and genotyped using TaqMan assays for SNPs in several inflammasome genes. Lower serum IL-18 (p = 0.049) and the IL-18 rs187238 G-carrier genotype (p = 0.042) were associated with severe fibrosis. The IL-18 rs1946518 TT genotype was associated with an increased risk of relapse (p = 0.05), whereas GG was related to better renal outcomes (p = 0.031). The rs187238 GG genotype was identified as a risk factor for mortality within the first year after AAV diagnosis, independent of the requirement for dialysis or lung involvement (p = 0.013). We suggest that decreased cytokine levels could be a surrogate marker of scarring and chronicity of the renal lesions, together with the rs187238 GG genotype. If our results are validated, the rs1946518 TT genotype predicts the risk of relapse and renal outcomes during follow-up.

Wegener's Granulomatosis Revealed by Nasal Pyramid Necrossis: A Case Report

Wegener's Granulomatosis Revealed by Nasal Pyramid Necrossis: A Case Report

Scleritis as the Presenting Sign of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis in the Setting of Temporal Arteritis.

Scleritis as the Presenting Sign of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis in the Setting of Temporal Arteritis.

Identification of an ANCA-Associated Vasculitis Cohort Using Deep Learning and Electronic Health Records.

ANCA-associated vasculitis (AAV) is a rare but serious disease. Traditional case-identification methods using claims data can be time-intensive and may miss important subgroups. We hypothesized that a deep learning model analyzing electronic health records (EHR) can more accurately identify AAV cases. We examined the Mass General Brigham (MGB) repository of clinical documentation from 12/1/1979 to 5/11/2021, using expert-curated keywords and ICD codes to identify a large cohort of potential AAV cases. Three labeled datasets (I, II, III) were created, each containing note sections. We trained and evaluated a range of machine learning and deep learning algorithms for note-level classification, using metrics like positive predictive value (PPV), sensitivity, F-score, area under the receiver operating characteristic curve (AUROC), and area under the precision and recall curve (AUPRC). The deep learning model was further evaluated for its ability to classify AAV cases at the patient-level, compared with rule-based algorithms in 2,000 randomly chosen samples. Datasets I, II, and III comprised 6,000, 3,008, and 7,500 note sections, respectively. Deep learning achieved the highest AUROC in all three datasets, with scores of 0.983, 0.991, and 0.991. The deep learning approach also had among the highest PPVs across the three datasets (0.941, 0.954, and 0.800, respectively). In a test cohort of 2,000 cases, the deep learning model achieved a PPV of 0.262 and an estimated sensitivity of 0.975. Compared to the best rule-based algorithm, the deep learning model identified six additional AAV cases, representing 13% of the total. The deep learning model effectively classifies clinical note sections for AAV diagnosis. Its application to EHR notes can potentially uncover additional cases missed by traditional rule-based methods.

The Use of "Acellbia"-A Biosimilar of Rituximab in Systemic Sclerosis.

The possibilities of modern therapy for systemic sclerosis (SSc) remains limited, since most of the used drugs do not have a disease-modifying effect. This encourages the study of new approaches that potentially affect the fundamental pathological processes underlying the disease. One example is anti-B-cell therapy, in particular rituximab (RTX). Until now RTX does not have a registration for the treatment of SSc, but there is a large positive experience of its use, which is reflected in recent meta-analyses and clinical recommendations. Complicated and expensive methods for obtaining genetically engineered biological drugs (biologics) have contributed to the emergence of more accessible biosimilars, one of which is the RTX biosimilar, Acellbia (Biocad, Russian Federation). The ''biosimilar'' versions of RTX might reduce the cost of therapy and increase patients accessibility to this treatment option. The RTX biosimilar Acellbia (ACB) has received approval in Russian Federation in 2014 for all indications held by reference RTX (including rheumatoid arthritis and ANCA-associated vasculitis).

Long-term surveillance study of rituximab originator treated patients with granulomatosis with polyangiitis (GPA)or microscopic polyangiitis (MPA).

Rituximab is used for remission induction and the prevention of relapse in anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). This study evaluated the incidence of safety events and compared time to first serious adverse event (SAE) between a rituximab cohort and a cohort treated with non-rituximab therapies in a real-life setting. Rituximab surveillance study in vasculitis was a retrospective observational study of patients with AAV who received rituximab (MabThera) or other treatments between 2003 and 2017 at a specialist vasculitis clinic. The primary endpoint was time to first SAE. 392 patients were enrolled: 247 in the rituximab and 145 in the control cohorts with a total follow up of 2217 person-years (mean study duration 5.7 years). Mean age was 61 years, 77% had granulomatosis with polyangiitis (GPA). There were differences in baseline characteristics (disease duration and prior immunosuppressive use) between groups. 134/247 patients (54%) in the rituximab and 58/145 (40%) of controls experienced at least one SAE. Time to first SAE was shorter in the rituximab group (hazard ratio (HR) 1.55, 95% CI 1.07-2.26, P = 0.022). Predictors of first SAE were higher vasculitis damage index and the presence of chronic pulmonary or kidney disease. The risk of serious infection was higher in the rituximab group (relative risk (RR) 2.12, 95% CI 1.31-3.43). Over 40% of patients with AAV experienced at least one SAE. Although shorter time to first SAE and higher risk of infection were observed in the rituximab group, baseline imbalances necessitate a careful interpretation of these results.

Dynamically changing antineutrophil cytoplasmic antibodies in granulomatosis with polyangiitis: A case report

BACKGROUND Granulomatosis with polyangiitis (GPA) is one of the most prevalent forms of the antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. GPA is characterized histologically by necrotizing granulomatous inflammation in addition to vasculitis. The diagnosis of GPA depends on clinical presentation, serological evidence of a positive ANCA, and/or histological evidence of necrotizing vasculitis or granulomatous destructive parenchymal inflammation. Cytoplasmic ANCA (c-ANCA) is positive in 65%-75% of GPA patients, accompanied by proteinase 3 (PR3), the main target antigen of c-ANCA, another 5% of GPA patients had negative ANCA. CASE SUMMARY The patient, a 52-year-old male, presented with unexplained nasal congestion, tinnitus, and hearing loss. After a duration of 4 months experiencing these symptoms, the patient subsequently developed fever and headache. The imaging examination revealed the presence of bilateral auricular mastoiditis and partial paranasal sinusitis, and the ANCA results were negative. The anti-infective therapy proved to be ineffective, but the patient's symptoms and fever were quickly relieved after 1 wk of treatment with methylprednisolone 40 mg once a day. However, after continuous use of methylprednisolone tablets for 3 months, the patient experienced a recurrence of fever accompanied by right-sided migraine, positive c-ANCA and PR3, and increased total protein in cerebrospinal fluid. The patient was diagnosed with GPA. After receiving a treatment regimen of intravenous methylprednisolone 40 mg/d and cyclophosphamide 0.8 g monthly, the patient experienced alleviation of fever and headache. Additionally, the ANCA levels became negative and there has been no recurrence. CONCLUSION For GPA patients with negative ANCA, there is a potential for early missed diagnosis. The integration of histopathological results and multidisciplinary communication plays a crucial role in facilitating ANCA-negative GPA.

Utility of Urinary CD4+ T-Cell Count in Detecting ANCA-Associated Vasculitis Renal Relapse.

Utility of Urinary CD4+ T-Cell Count in Detecting ANCA-Associated Vasculitis Renal Relapse.

FTY720 ameliorates experimental MPO-ANCA-associated vasculitis by regulating fatty acid oxidation via the neutrophil PPARα-CPT1a pathway.

Increasing studies demonstrated the importance of C5a and anti-neutrophil cytoplasmic antibody (ANCA)-induced neutrophil activation in the pathogenesis of ANCA-associated vasculitis (AAV). Sphingosine-1-phosphate (S1P) acts as a downstream effector molecule of C5a and enhances neutrophil activation induced by C5a and ANCA. The current study investigated the role of a S1P receptor modulator, FTY720, in experimental autoimmune vasculitis (EAV) and explored the immunometabolism-related mechanisms of FTY720 in modulating ANCA-induced neutrophil activation. The effects of FTY720 in EAV were evaluated by quantifying haematuria, proteinuria, crescent formation, tubulointerstitial injury and pulmonary haemorrhage. RNA sequencing of renal cortex and gene enrichment analysis were performed. The proteins of key identified pathways were analysed in neutrophils isolated from peripheral blood of patients with active AAV and normal controls. We assessed the effects of FTY720 on ANCA-induced neutrophil respiratory burst and neutrophil extracellular traps formation (NETosis). FTY720 treatment significantly attenuated renal injury and pulmonary haemorrhage in EAV. RNA sequencing analyses of renal cortex demonstrated enhanced fatty acid oxidation (FAO) and peroxisome proliferator-activated receptor (PPAR) signalling in FTY720-treated rats. Compared with normal controls, patients with active AAV showed decreased FAO in neutrophils. FTY720-treated differentiated HL-60 cells showed increased expression of carnitine palmitoyltransferase 1a (CPT1a) and PPARα. Blocking or knockdown of CPT1a or PPARα in isolated human neutrophils and HL-60 cells reversed the inhibitory effects of FTY720 on ANCA-induced neutrophil respiratory burst and NETosis. FTY720 attenuated renal injury in EAV through upregulating FAO via the PPARα-CPT1a pathway in neutrophils, offering potential immunometabolic targets in AAV treatment.

Kidney transplantation in patients with ANCA-associated vasculitis is associated with a high incidence of post-transplant cancer

BackgroundAntineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare disease with limited data on outcomes after transplantation.MethodsIn this single-center retrospective cohort study, we describe the outcomes of kidney transplant patients with AAV transplanted at our institute from February 2006 to January 2022.ResultsWe identified 9 patients among 1026 with a pre-transplant diagnosis of AAV; all patients had received previous treatment with cyclophosphamide. Maintenance immunosuppression after transplantation was tacrolimus-based in 89% of the patients. At the end of a mean follow-up of 132 ± 61.1 months after transplantation, only one case of extrarenal vasculitis relapse was observed. The relapse rate was 0.01 per patient per year, which is comparable to that reported in the literature. However, seven patients were diagnosed with cancer after a mean follow-up of 81.4 months after transplantation; six had skin cancer and three had renal cell carcinoma (RCC) of the native kidneys (cumulative incidence of 78%). One patient died from metastatic squamous cell carcinoma.ConclusionIn this study, we found a noticeable decrease in disease relapse (1 relapse in the present cohort vs 7 relapses in 19 patients in the previous cohort) in kidney transplant patients with AAV compared with previous data from our group (December 1987–January 2006). Conversely, we found a high incidence of post-transplant cancer. This result could be attributed to reduced immunosurveillance due to immunosuppression therapy before and after transplantation. Therefore, constant cancer early diagnosis and prevention is mandatory during the post-transplant follow-up of AAV patients.Graphical abstract

Urinary complement biomarkers in immune-mediated kidney diseases.

The complement system, an important part of the innate system, is known to play a central role in many immune mediated kidney diseases. All parts of the complement system including the classical, alternative, and mannose-binding lectin pathways have been implicated in complement-mediated kidney injury. Although complement components are thought to be mainly synthesized in the liver and activated in the circulation, emerging data suggest that complement is synthesized and activated inside the kidney leading to direct injury. Urinary complement biomarkers are likely a better reflection of inflammation within the kidneys as compared to traditional serum complement biomarkers which may be influenced by systemic inflammation. In addition, urinary complement biomarkers have the advantage of being non-invasive and easily accessible. With the rise of therapies targeting the complement pathways, there is a critical need to better understand the role of complement in kidney diseases and to develop reliable and non-invasive biomarkers to assess disease activity, predict treatment response and guide therapeutic interventions. In this review, we summarized the current knowledge on urinary complement biomarkers of kidney diseases due to immune complex deposition (lupus nephritis, primary membranous nephropathy, IgA nephropathy) and due to activation of the alternative pathway (C3 glomerulopathy, thrombotic microangiography, ANCA-associated vasculitis). We also address the limitations of current research and propose future directions for the discovery of urinary complement biomarkers.