Antineutrophil Cytoplasmic Antibody Research Articles

Identification of Fatty Acid-Binding Protein 4 as a Potential Biomarker and Therapeutic Target for ANCA-Associated Glomerulonephritis

Introduction: Fatty acid-binding protein 4 (FABP4) is a novel adipokine that is critically involved in many inflammatory and immune diseases. However, the role of FABP4 in anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (ANCA-GN) remains unclear. The current study aimed to investigate the role of FABP4 in patients with ANCA-GN. Methods: Plasma and urine samples from 37 patients with active ANCA-GN and kidney biopsy specimens from another group of 56 patients with ANCA-GN were collected. The plasma and urinary level of FABP4 were measured by enzyme-linked immunosorbent assay and the kidney FABP4 expression was determined by immunohistochemistry and immunofluorescence staining. Associations between FABP4 levels with clinical and pathologic parameters were analyzed. To further elucidate the role of FABP4 in ANCA-GN, a novel FABP4 inhibitor BMS309403 was employed in a recognized rat model of experimental autoimmune vasculitis (EAV). Results: Plasma and urinary levels of FABP4 in active ANCA-GN patients were significantly higher than those in normal controls (52.8 ± 23.6 ng/ml vs. 16.9 ± 8.8 ng/ml, P<0.01; median 126.6 [interquartile range (IQR) 28.4-311.2] ng/g Cr vs. median 0.0 [IQR 0.0-0.0] ng/g Cr, P<0.01, respectively). Immunohistochemical analysis revealed higher glomerular and tubular expression of FABP4 in the kidneys of ANCA-GN patients than those in normal controls (0.015 ± 0.012 vs. 0.004 ± 0.003, P<0.001; 0.053 ± 0.026 vs. 0.011 ± 0.010, P<0.001, respectively). Moreover, for ANCA-GN patients, urinary FABP4 levels were significantly higher in active ANCA than those in remission (184.3 ± 187.0 ng/g Cr vs. 9.4 ± 23.9 ng/g Cr, P<0.01). Correlation analysis showed that urinary levels of FABP4 correlated with serum creatinine (r=0.596, P<0.0001), urinary albumin/Cr (r=0.523, P=0.001), blood neutrophil ratio (r=0.386, P=0.018), PT (r=0.583, P=0.001), APTT (r=0.364, P=0.034), hemoglobin level (r=-0.398, P=0.015), eGFR (r=-0.680, P<0.0001), crescent proportion (r=0.661, P=0.032) and all-cause death of ANCA-GN patients (HR 2.93, 95%CI (1.05-8.19)). Furthermore, FABP4 inhibition by BMS309403 ameliorated renal injury in a rat mole of ANCA-GN. Conclusions: Urinary FABP4 levels might reflect the disease activity and renal involvement of ANCA-associated vasculitis, and FABP4 might act as a promising therapeutic target against ANCA-GN.

An association between MEFV mutation and ANCA-associated vasculitis involving the central nervous system and lungs: causality under scrutiny

Familial Mediterranean fever (FMF) is traditionally associated with biallelic mutations in the MEFV gene; however, heterozygous mutations may also contribute to disease phenotypes. We report the case of a 42-year-old woman with heterozygous p.Met694Ile MEFV mutation, presenting with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis involving the central nervous system and lungs. Her clinical course was marked by immune dysregulation, autoimmunity and inflammatory manifestations, including urticarial neutrophilic dermatoses and IgM deficiency. This case highlights the potential pathogenic role of heterozygous MEFV mutations in ANCA-associated vasculitis, expanding the clinical spectrum of FMF-related inflammatory diseases. Genetic investigation is essential in patients with overlapping autoimmune and autoinflammatory features to guide appropriate diagnosis and management.

Comprehensive characteristics of pulmonary antineutrophil cytoplasmic antibody-associated vasculitis and the development of a predictive nomogram for mortality.

Antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) is a rare and potential devastating disease with high mortality, frequently with pulmonary involvement. Our study aimed to explore the pulmonary features of AAV and identify predictors of long-term survival. We retrospectively analyzed 538 AAV patients diagnosed between January 2013 and July 2019, with follow-up data extending to August 2020. The Least absolute shrinkage and selection operator (LASSO) regression analysis was employed to identify variables predictive of mortality. Subsequently, a nomogram was developed, with its predictive accuracy and discrimination assessed by the concordance index and calibration curves, respectively. A total of 460 (85.5%) AAV patients presented with pulmonary involvement. The mortality was 36.8%. Patients with pulmonary involvement more frequently exhibited respiratory symptoms, predominantly interstitial lung disease on radiographs, and were at higher risk for respiratory failure, diffuse alveolar hemorrhage, mechanic ventilation and death (All P<0.05). The LASSO regression pinpointed 16 predictors of mortality, and the predictive model demonstrated an area under the curve of 0.810. The nomogram, based on these variables, achieved a concordance index of 0.825, with calibration curve indicating excellent predictive agreement. The study establishes a predictive model for AAV mortality with high accuracy, offering insights crucial for patient care. Pulmonary involvement, prevalent and linked to higher mortality, underscores the need for precise predictive tools in AAV management.

Defining cause of death in a contemporary cohort with ANCA-associated vasculitis (AAV): A comparison of electronic health record and death certificate data.

Patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) face excess mortality compared with the general population. Mortality in clinical epidemiology research is often examined using death certificate diagnosis codes; however, the sensitivity of such codes in AAV is unknown. We performed a retrospective cohort study using the Mass General Brigham AAV Cohort, including patients with AAV who died between 2002 and 2019. Causes of death were determined by electronic health record (EHR) review (reference gold standard) and via cause of death diagnosis codes on death certificates. We calculated the sensitivity of death certificate diagnosis codes for AAV. Of 684 patients in the registry, 184 died, 92 (52 %) of whom had adequate EHR data available determine cause of death and 72 (40 %) of whom had both EHR and death certificate data available. Death due to AAV, infection, cardiovascular disease, and cancer occurred in 8 %, 29 %, 5 %, and 18 %, respectively, when ascertained by manual review, as opposed to 0 %, 11 %, 25 %, and 21 %, as determined by death certificates. The sensitivity of AAV diagnosis codes for AAV was 16.6 % (95 % CI: 10.5, 22.6) among all patients with death certificate data available. In a contemporary cohort of patients with AAV, infection was the most common cause of death, while death due to AAV itself was rare. We found a high degree of discordance between causes of death determined by manual review and death certificate diagnosis codes. Mortality research on AAV should include linkage to medical records data to reduce potential bias.

WCN25-1471 IgA Nephropathy with Anti-Neutrophil Cytoplasmic Antibodies in a Middle-Aged Patient

WCN25-1471 IgA Nephropathy with Anti-Neutrophil Cytoplasmic Antibodies in a Middle-Aged Patient

Ontology-based integration and querying of heterogeneous rare disease data sources – POLVAS perspective

The integration of rare disease medical databases belonging to different countries is an important problem, as a large number of observations are required for reliable statistical inference of patient data in order to facilitate clinical research. Such integration of national registry data, which requires harmonisation of the heterogeneous data sets into a unified view, is facilitated in the European FAIRVASC project by developing a domain-specific ontology. The FAIRVASC project is dedicated to the rare disease of anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV). This paper focuses on the practical issues and challenges, encountered during the process of integrating the Polish national database POLVAS into the federated database within the FAIRVASC project. It discusses the use of ontology-based methods for data integration and the importance of ensuring patient privacy and data protection. It addresses the problem of missing information in POLVAS, which can be obtained by aggregating other data available within the database, incompatibility of data types and formats, and mapping polish data names into the common vocabulary. The modifications of mappings used to ‘uplift’ national data into the Resource Description Framework (RDF) triplestore are also proposed. The described methods allow for integrating the Polish national database into the European network over which federated queries are performed.

A classification criteria-based gating strategy improves anti-neutrophil cytoplasmic antibody testing performance characteristics for ANCA-associated vasculitis diagnosis

A classification criteria-based gating strategy improves anti-neutrophil cytoplasmic antibody testing performance characteristics for ANCA-associated vasculitis diagnosis

Two Decades Rituximab Therapy in Anti-Neutrophil Cytoplasmic Antibody Associated Vasculitis.

Remission failure and relapse numerate as one of the main problems in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAVs). The need for new agents that provide effective and safe induction accompanied by sustained remission seems to be urgent in clinical care. The efficacy and safety of rituximab (RTX) for AAVs therapy has been reported in various studies. RTX therapy offers several advantages to treating AAVs patients compared to other therapeutic approaches including reduction of Glucocorticoids (GCs) and conventional Immunosuppressive therapy (IST) usage during both the induction of remission and maintenance phases. This reduction can lead to a lower rate of serious complications making RTX therapy a safer option. It seems that RTX may provide improved clinical outcomes in these patients mediated via B-lymphocyte depletion, Proteinase 3-antineutrophilic cytoplasmic antibody (PR3-ANCA), and myeloperoxidase-antineutrophilic cytoplasmic antibody (MPO-ANCA) titers reduction. In this regard, some uncertainties have been reported to validate the association between such depletion and clinical improvement, as suggested by other sources of autoreactive B cells that did not target with RTX. Due to the prolonged B cell depletion, fixed intervals and adjusted dosage of RTX may be required in patients with AAVs. In this narrative review, we aimed to insight better understand regarding the efficacy of RTX for effective induction and sustained remission in patients with AAVs. It seems that discovering new biomarkers predicting relapse in AAVs patients can lead to future targeted therapy.

Routine ordering of anti-neutrophil cytoplasmic antibody for suspected autoimmune disease and vasculitis has low diagnostic utility

Routine ordering of anti-neutrophil cytoplasmic antibody for suspected autoimmune disease and vasculitis has low diagnostic utility

Case report: Spontaneous renal hemorrhage in anti-neutrophil cytoplasmic antibody-associated vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic necrotizing vasculitis that predominantly affects small vessels. In this report, we present a typical case of granulomatosis with polyangiitis (GPA) complicated by spontaneous renal hemorrhage (SRH), a rare but potentially severe condition. The patient developed SRH during immunosuppressive therapy but recovered following conservative treatment. We then conducted a systematic literature review on SRH in the context of AAV, and analyzed clinical features, management strategies, and patient prognosis. A total of 15 patients were enrolled for statistical analysis, comprising the one case reported in the current study and 14 from the literature. Of these patients, nine presented with GPA and six showed microscopic polyangiitis (MPA), with a sex distribution of 3:2 males to females. The average patient age was 54.5 years, and ranged from 25 to 82 years. Acute flank pain was the most common clinical manifestation, and was occasionally accompanied by anemia and shock. Treatment varied for the different patients. Eight patients received glucocorticoid and immunosuppressive agents that included rituximab, cyclophosphamide, and azathioprine; five patients underwent transcatheter arterial embolization (TAE); and one patient underwent nephrectomy. Our findings indicate that SRH typically occurs early in the course of AAV and correlates with disease activity, with renal aneurysm rupture as the primary cause. More than half of the patients respond well to corticosteroids and immunosuppressants. Timely TAE is essential for patients showing persistent deterioration despite conservative management.

Sex-specific association of immunological markers in CS-delivered newborns with pre-pregnancy body mass index and gestational weight gain of mothers

Just as overweight and obesity may impair immunity, excessive body weight-related parameters of women in the pre-conception period and during pregnancy are possible detrimental factors for fetal programming of the immune system in their offspring. We investigated the relationship of pre-pregnancy body mass index (pBMI) and gestational weight gain (GWG) of mothers with the placental transport rate (PTR) of IgG antibodies and antineutrophil cytoplasmatic antibodies against lactoferrin (Lf-ANCA) and their concentration in umbilical cord blood serum (UCS), verifying the sex-specificity of this relationship. The examined group of this cross-sectional pilot study consisted of 101 pregnant women and their healthy CS-delivered newborn children. The concentration of antibodies in maternal serum (MS) and UCS were determined by ELISA method. PTR was assessed as a ratio of the concentration of antibodies in the UCS and MS. A significantly lower PTR of IgG and their concentration in the UCS were demonstrated in newborns of mothers with an excessive pBMI compared to those with pBMI < 25 and the association was more pronounced in male newborns. The lowest PTR of beneficial IgG and their concentration in the UCS as well as the highest PTR of detrimental Lf-ANCA and their concentration in UCS were observed in newborns born to mothers with co-occurrence of both an excessive pBMI and GWG. It seems that maternal preconception overweight and obesity along with an excessive GWG can be a predictor of unfavorable immune effects in fetuses. Further studies are needed to explain the role of maternal weight-related parameters in the development of immunological health of their offspring.

P0584 Rituximab versus infliximab for the treatment of PR3-ANCA Positive Moderately to Severely Active Ulcerative Colotis: A retrospective Multicentre Real-World Study

Abstract Background Patients with ulcerative colitis (UC) who are positive for anti-neutrophil cytoplasmic antibodies(ANCA) tend to have a poor response to infliximab(IFX)1-3. We aimed to evaluate the comparative efficacy and safety of rituximab (RTX) versus IFX in moderately to severely active UC patients who are Proteinase 3-ANCA(PR3-ANCA) positive. Methods This retrospective multicentre real-world study encompassed three medical centres in Hubei, China. Patients with moderate to severely active UC who are positive for PR3-ANCA were categorized into the RTX group(100mg or 200mg by intravenous injection every 2 weeks for a total dose between 400mg and 900mg, n=12) and IFX group(5 mg/kg of intravenous at weeks 0, 2, and 6, followed by maintenance doses every 8 weeks, n=26) based on the biological therapy. The Mayo Clinic Score (MCS) was utilised to evaluate the efficacy endpoints at week 22, encompassing clinical remission(primary endpoint), clinical response, endoscopic response, endoscopic improvement, and endoscopic remission. Safety endpoints focused on opportunistic infections and drug-related adverse reactions. Inverse probability of treatment weighting(IPTW) and multifactorial logistic regression analysis(MLRS) were employed to mitigate the effects of potential confounding factors. Results The rates of clinical remission(83.33% vs. 23.08% and 93.20% vs. 25.40%), clinical response(100.00% vs. 65.38% and 100.00% vs. 64.60%), endoscopic response(100.00% vs. 34.62% and 100.00% vs. 36.06), endoscopic improvement(50.00% vs. 11.54% and 75.07% vs. 11.29%), and endoscopic remission(100.00% vs. 34.62% and 100.00% vs. 36.06%) were significantly higher in patients treated with RTX compared with those treated with IFX, both prior to and following IPTW(all P&amp;lt;0.05). In MLRS, RTX was associated with higher odds of achieving clinical remission at week 22 versus IFX before and after IPTW[OR(95%CI): 143.854(1.060-19521.653) and 190.499(4.147-1.000*105), all P&amp;lt;0.05]. In terms of safety endpoints, elevated interferon-gamma release assays(IGRAs) were noted in none of the RTX patients, and 2 IFX patients (7.69%). No patients exhibited elevated EBV-DNA, HBV-DNA, CMV-DNA, or experienced severe infections. Conclusion RTX demonstrated superior efficacy versus IFX in moderately to severely active UC patients with positive PR3-ANCA, with a comparable safety profile.

P1111 Infliximab is not Superior to Vedolizumab for the Treatment of Moderately to Severely Active Ulcerative Colotis with PR3-ANCA Positive : A Retrospective Multicentre Real-World Study

Abstract Background Current literature presents conflicting findings about the efficacy of Infliximab (IFX) versus vedolizumab (VDZ) in patients with moderately to severely active ulcerative colitis (UC). Patients with UC who are positive for anti-neutrophil cytoplasmic antibodies(ANCA) are known to respond poorly to IFX1-3 and VDZ4. We aimed to evaluate the comparative efficacy and safety of IFX versus VDZ in moderately to severely active UC patients with Proteinase 3-ANCA(PR3-ANCA) positive. Methods This retrospective multicentre real-world study was conducted in three centers in Hubei, China. Patients with moderate to severe active ulcerative colitis (UC) who are positive for PR3-ANCA were allocated to either the Vedolizumab (VDZ) group (n=19) or the Infliximab (IFX) group (n=26) depending on the biologics they received. The endpoints assessed at week 22 included clinical remission(primary endpoint), clinical response, endoscopic response, and endoscopic remission. Inverse probability of treatment weighting (IPTW) was employed to ensure the reliability and robustness of the clinical outcomes. Results In the original cohort, IFX was not superior to VDZ in terms of clinical remission (23.08% vs. 42.11%, P=0.173), clinical response (65.38% vs. 63.16%, P=0.878), endoscopic response (57.69% vs. 63.16%, P=0.712), and endoscopic remission (11.54% vs. 26.32%, P=0.253). Additionally, similar outcomes were observed in the IPTW cohort: for clinical remission (23.26% vs. 35.89%, P=0.384), clinical response (68.68% vs. 60.29%, P=0.583), endoscopic response (58.48% vs. 60.29%, P=0.912), and endoscopic remission (14.18% vs. 22.75%, P=0.494) when comparing IFX to VDZ. Conclusion IFX is not superior efficacy compared to VDZ in moderately to severely active UC patients with PR3-ANCA positive.

Double-Positive Anti-GBM and ANCA Vasculitis: 2 Case Reports and Review of the Literature

Double-Positive Patients (DPPs), characterized by the simultaneous presence of Anti-Neutrophil Cytoplasmic Antibody (ANCA) and anti-Glomerular Basement Membrane (anti-GBM) antibodies, represent a rare subset in systemic vasculitis. We present two cases of DPPs with renal involvement and review the existing literature to elucidate the clinical characteristics, histopathological findings, management strategies, and prognostic outcomes associated with this condition. Both cases exhibited renal involvement with rapidly progressive glomerulonephritis, requiring renal replacement therapy. Renal biopsies confirmed crescentic glomerulonephritis with features of both anti-GBM disease and ANCA-associated vasculitis. Management included high-dose glucocorticoids, cyclophosphamide, and consideration of plasma exchanges. Double-positive ANCA and anti-GBM vasculitis pose challenges in management and prognosis. Further research is essential to improve therapeutic strategies for this rare and heterogeneous condition.

Diagnosing and Treating ANCA-Associated Vasculitis within the COVID-19 Era: A Challenging Case Report

Introduction: Anti-neutrophil cytoplasmic antibody (ANCA)- associated vasculitis (AAV) is a rare group of systemic autoimmune diseases that primarily target small blood vessels. Renal manifestations often present as pauci-immune focal and segmental necrotizing crescentic glomerulonephritis (PI-NCGN), which can progress to acute or chronic kidney failure and multiorgan involvement. It is frequently associated with poor outcomes. We report a case of PR3-positive ANCA-associated vasculitis complicated by rapidly progressive glomerulonephritis, acute kidney injury, and diffuse alveolar hemorrhage during the COVID-19 pandemic. This case highlights the diagnostic challenges of differentiating AAV from conditions associated with SARS-CoV-2 infection, as the clinical and radiological presentations of pulmonary-renal syndromes may overlap. The findings underscore the importance of maintaining a comprehensive differential diagnosis in patients with pulmonary and renal involvement, particularly in the post-COVID-19 era, to ensure timely and accurate management of rare autoimmune conditions such as AAV. Conclusion: ANCA-associated vasculitis (AAV) remains a diagnostic and therapeutic challenge, particularly in the post-COVID-19 era, where overlapping clinical and radiological features with SARS-CoV-2 complications can obscure timely identification. This case highlights the critical importance of maintaining a broad differential diagnosis in patients presenting with pulmonary-renal syndromes to differentiate AAV from more common conditions associated with COVID-19.

Acute therapeutic effects and pathophysiology of eosinophilic granulomatosis with polyangiitis neuropathy

ObjectiveThis study investigated the effects of early treatment and pathophysiology on eosinophilic granulomatosis with polyangiitis neuropathy (EGPA-N).MethodsTwenty-six consecutive patients with EGPA-N were diagnosed and treated within a day of admission...

Multiple Myeloma: A Forgotten Imitator of Anti-Neutrophil Cytoplasmic Antibody (ANCA) Vasculitis

Multiple Myeloma: A Forgotten Imitator of Anti-Neutrophil Cytoplasmic Antibody (ANCA) Vasculitis

ANCA-assoziierte Vaskulitis: Komplementblockade als Therapieoption auch bei schwerer Lungenbeteiligung

Background: Pulmonary haemorrhage with hypoxia caused by anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has a high early mortality. Avacopan, an oral C5a receptor antagonist, is an approved treatment for AAV, but patients with pulmonary haemorrhage requiring invasive pulmonary ventilation support were excluded from the Avacopan for the Treatment of ANCA-Associated Vasculitis (ADVOCATE) Trial. Methods: A retrospective, observational, multicentre case series of AAV patients with hypoxic pulmonary haemorrhage, requiring oxygen support or mechanical ventilation, who received avacopan. Results: Eight patients (62.5% female), median age 64 years (range 17–80), seven with kidney involvement, median estimated glomerular filtration rate (eGFR) 11 (range 5–99) mL/min/1.73 m2, were followed for a median of 6 months from presentation. Seven were newly diagnosed (87.5%), five were myeloperoxidase-ANCA and three proteinase 3-ANCA positive. All had hypoxia, four requiring mechanical ventilation (three invasive and one non-invasive). Intensive care unit (ICU) stay for the four patients lasted a median of 9 days (range 6–60). Four received rituximab and cyclophosphamide combination, three rituximab and one cyclophosphamide. Four underwent plasma exchange and one received 2 months of daily extracorporeal membrane oxygenation therapy. Following the initiation of avacopan after a median of 10 days (range 2–40), pulmonary haemorrhage resolved in all patients, even the two who had 1 month of refractory pulmonary haemorrhage prior to avacopan. Additionally, after 1 month, the median prednisolone dose was 5 mg/day (range 0–50), with three patients successfully discontinuing steroid use. Two patients suffered serious infections, two discontinued avacopan, one permanently due to a rash and one temporarily after 3 months due to neutropenia. All patients survived and no re-hospitalization occurred.

POSTERIOR SCLERITIS: REVIEW OF LITERATURE AND FIRST CASE REPORT FROM YEMEN

A rare inflammatory eye illness that involves the posterior regions of the sclera. Posterior scleritis is very rare in children and more common in women. Ocular pain, headaches, and vision loss are some of its frequently vague clinical manifestations. Rheumatic conditions including systemic lupus erythematous (SLE), anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis and rheumatoid arthritis (RA) are frequently linked to the scleritis pathogenesis. A comprehensive clinical eye exam is necessary to diagnose posterior scleritis because it can mimic many other ocular disorders. Laboratory tests may reveal underlying systemic disorders, such as rheumatic disease and inflammatory markers. A precise diagnosis is aided by imaging, such as magnetic resonance imaging (MRI) and B-scan ultrasonography. Treatment includes non-steroidal anti-inflammatory drugs (NSAIDs), topical corticosteroids for moderate disease, and systemic corticosteroids for severe disease. For refractory instances, biologic therapy has grown in importance. To treat this potentially blinding condition, a multidisciplinary strategy combining rheumatology and ophthalmology is essential. This case report focuses on a 9-year-old boy who has posterior scleritis and no history of rheumatic disorders or other infections or non-infectious diseases. Peer Review History: Received 6 September 2024; Reviewed 8 November; Accepted 21 December; Available online 15 January 2025 Academic Editor: Dr. Nuray Arı, Ankara University, Turkiye, ari@ankara.edu.tr Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 7.5/10

Evaluating Renal Disease in Pediatric-Onset Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: Disease Course, Outcomes, and Predictors of Outcome.

We aimed to study the disease course, outcomes, and predictors of outcome in pediatric-onset antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) affecting the kidneys. Patients eligible for this study had a diagnosis of granulomatosis with polyangiitis (GPA), microscopic polyangiitis, or ANCA-positive pauci-immune glomerulonephritis, were 18 years or younger at diagnosis, had renal disease defined by biopsy or dialysis dependence, and had clinical data at diagnosis and at either 12 or 24 months. Ambispective data from A Registry for Children with Vasculitis/Pediatric Vasculitis Initiative Registry was used. The primary outcome was inactive renal disease (pediatric vasculitis activity score = 0 or 1) at 12 months. Secondary outcomes included rates of improved renal function and damage within 24 months. Renal function, defined by estimated glomerular filtration rate, was categorized into Kidney Disease Improving Global Outcomes (KDIGO) stages at diagnosis and tested as a predictor of outcome using a proportional-odds logistic regression model. A total of 145 patients were included: 68% were female, and 78% had GPA. At 12 months, 83% of patients achieved inactive renal disease; however, 42% had evidence of permanent renal damage. Compared with patients with normal renal function at diagnosis, patients with moderate to severely reduced renal function, or kidney failure at diagnosis, had an odds ratio of 8.62 (P = 0.002; 95% confidence interval [CI] 2.31-32.1) and 26.3 (P < 0.001; 95% CI 6.32-109), respectively, for being in a non-normal KDIGO category at 12 months. The majority of patients with pediatric AAV achieve inactive renal disease by 12 months; however, almost half have evidence of damage. Renal function at diagnosis is a strong predictor of renal function at 12 months.