Renal Vasculitis Research Articles

Diagnosis and Treatment of Renal ANCA Vasculitis: A Summary of the Consensus Document of the Catalan Group for the Study of Glomerular Diseases (GLOMCAT)

The document provides a comprehensive overview of the diagnosis, monitoring, and treatment of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) with renal involvement, focusing on granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). It outlines the definitions, clinical presentation, histopathological classification, monitoring strategies, induction and maintenance treatments, as well as special considerations for relapsing, refractory, and frail patients with renal AAV. The document was prepared by the Catalan Group for the Study of Glomerular Diseases (GLOMCAT), which comprises nephrologists with extensive experience in the diagnosis and treatment of AAV patients. Several virtual and face-to-face meetings were held for coordination, section assignments, and content discussion. An exhaustive and systematic search of the literature was carried out, which included, among others, the following databases: PubMed, EMBASE, Cochrane Library, Google Scholar, and ClinicalTrials.gov, as well as the abstract books of national and international congresses. Overall, the document provides a comprehensive guide for clinicians managing patients with renal AAV, offering evidence-based recommendations for diagnosis, monitoring, and treatment across various clinical scenarios.

Vasculitis associated with VEXAS syndrome.

To define the prevalence, distribution, and characteristics of patients with VEXAS who have confirmed vasculitis. Patients with VEXAS syndrome, verified by positive UBA1 mutation, were included. Chart review was performed to identify. characteristics and outcomes. Vasculitis diagnosis was based on either histopathology showing vascular inflammation or non-invasive angiography findings. Summary statistics were calculated. Eighty-nine patients met inclusion criteria. All were male with a median age of onset of 66.9 years (IQR 60.1, 72.7). Median (IQR) follow up was 3.8(2.2-5.5) years during which 21 patients (23.6%) had evidence of vasculitis. Vasculitis subtypes included small vessel vasculitis (19.1%), cutaneous medium vessel vasculitis (2.2%), and large vessel vasculitis (2.2%). No patient had more than one vessel size involved. Histopathology in small vessel vasculitis patients was consistent with cutaneous leukocytoclastic vasculitis in the majority, though one patient had leukocytoclastic peritubular capillaritis on renal biopsy. Cranial symptoms (headache, vision changes, or jaw pain) were noted in 18.0%. Two additional patients not experiencing cranial symptoms exhibited large vessel involvement with confirmed carotid thickening on non-invasive angiography; one of these had a positive temporal artery biopsy. VEXAS syndrome manifests as a variable vessel vasculitis in a quarter of patients, with cutaneous small and medium vessel involvement being particularly common. Some patients may have positive ANCA serologies or even renal vasculitis leading to misdiagnosis. Cranial symptoms are common and may mimic giant cell arteritis, though documented large vessel inflammation is rare.

National Trends and Outcomes of Hospitalizations among Patients with Renal Vasculitides

National Trends and Outcomes of Hospitalizations among Patients with Renal Vasculitides

Elderly Patients' Prognostic Disadvantage Might Be Substantiated by Distinct Tubulointerstitial Lesions in Newly Diagnosed ANCA-Associated Renal Vasculitis

Elderly Patients' Prognostic Disadvantage Might Be Substantiated by Distinct Tubulointerstitial Lesions in Newly Diagnosed ANCA-Associated Renal Vasculitis

Clinical, Serologic, and Histologic Characteristics of Pauci-Immune Renal Vasculitis and Its Response to Treatment in a Mexican Population

Clinical, Serologic, and Histologic Characteristics of Pauci-Immune Renal Vasculitis and Its Response to Treatment in a Mexican Population

Low Albumin Levels Are Associated with Intrarenal Complement C4d Deposits in Critically Ill Patients with ANCA-Associated Renal Vasculitis

Low Albumin Levels Are Associated with Intrarenal Complement C4d Deposits in Critically Ill Patients with ANCA-Associated Renal Vasculitis

Renal vascular lesions in childhood-onset lupus nephritis.

This study aimed to determine the clinical significance of renal vascular lesions (RVLs) in childhood-onset lupus nephritis (cLN). We retrospectively reviewed all children with biopsy-proven cLN between 2004-2020 to evaluate the prevalence of RVLs on kidney biopsy and its associated factors and long-term outcomes. The composite kidney outcome was defined as advanced chronic kidney disease (CKD) stage 3-5, kidney failure and death. 107 biopsies from 84 Chinese patients were analysed. RVLs were observed in 19 patients (22.6%), including non-inflammatory necrotizing vasculopathy (NNV, n = 6), thrombotic microangiopathy (TMA, n = 4), arterial sclerosis (AS, n = 3), concurrent NNV with AS (n = 4), concurrent NNV with TMA (n = 1) and concurrent true renal vasculitis with AS (n = 1). The presence of RVLs was associated with lower estimated glomerular filtration rate (eGFR) (66.9 ± 40.3 vs. 95.6 ± 39.4ml/min/1.73m2, p = 0.005), haemoglobin level (9.1 ± 1.9 vs. 10.4 ± 1.9g/dL, p = 0.008) and platelet count (150.1 ± 96.4 vs. 217.2 ± 104.8 × 109/L, p = 0.01). LN classes and activity/chronicity indices were similar. Patients with RVLs had poorer composite kidney outcomes, though not reaching statistical significance (log-rank test, p = 0.06). The presence of NNV was associated with inferior survival free from composite kidney outcome (log-rank test, p = 0.0018), compared to other forms of RVLs and those without RVLs. Univariate analysis revealed NNV (HR 7.08, 95% CI 1.67-30.03) was predictive of composite kidney outcome. RVLs are present in one-fifth of cLN patients and are associated with severe presentation. NNV is associated with worse long-term kidney outcome. Routine evaluation of RVLs is warranted and should be incorporated into future classification criteria.

Myeloperoxidase-ANCA IgG induces different forms of small vessel vasculitis based on type of synergistic immune stimuli

Anti-neutrophil cytoplasmic autoantibody (ANCA) vasculitis has diverse patterns of injury including microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Necrotizing and crescentic glomerulonephritis (NCGN) occurs in all syndromes and as renal limited vasculitis (RLV). Single dose intravenous ANCA IgG-specific for mouse myeloperoxidase (MPO) causes RLV in mice. Although multiple mouse models have elucidated ANCA-IgG induced necrotizing and crescentic glomerulonephritis (NCGN), pathogenesis of ANCA-induced granulomatosis and vasculitis outside the kidney has not been clarified. To investigate this, we used intravenous MPO-ANCA IgG in the same strain of mice to induce different patterns of lung disease mirroring patients with granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Repeated intravenous MPO-ANCA IgG induced GPA with NCGN, lung capillaritis, arteritis and granulomatosis. Lung leukocyte phenotypes were evaluated by immunohistochemical image analysis and by flow cytometry. ANCA lung capillaritis and microabscesses began within one day and evolved into granulomas in under seven days. Influenza plus single dose MPO-ANCA IgG induced MPA with NCGN, lung capillaritis and arteritis, but no granulomatosis. Allergic airway disease caused by house dust mites or ovalbumin plus single dose intravenous MPO-ANCA IgG induced EGPA with eosinophilic bronchiolitis, NCGN, capillaritis, arteritis, and granulomatosis. Thus, our study shows that the occurrence and pattern of lung lesions are determined by the same ANCA IgG accompanied by different synergistic immune factors.

A case of renal limited myeloperoxidase anti-neutrophil cytoplasmic antibody-positive vasculitis treated with maintenance avacopan monotherapy.

A 76-year-old woman was admitted with progressive renal function decline. A kidney biopsy was performed because of myeloperoxidase anti-neutrophil cytoplasmic antibody (ANCA; 333IU/mL), proteinuria (1.21g/d), and urinary erythrocyte sediment (10-19/high-power field). Renal-limited ANCA-positive vasculitis with pauci-immune necrotizing crescentic glomerulonephritis (ANCA-associated vasculitis, AAV) was diagnosed. Glucocorticoid therapy was started, and the patient responded well. About 1year later, avacopan treatment was started and glucocorticoid therapy was discontinued. Avacopan did not normalize ANCA levels and did not make urinary findings negative. However, further progression of renal function decline is prevented. Factors attributed to the development of AAV in this case were investigated; AAV developed after the second dose of the COVID-19 vaccine and ANCA levels re-elevated after the fifth dose. This suggests that the COVID-19 vaccine may have contributed to the development of AAV in this elderly patient. Avacopan monotherapy has been shown to be effective as maintenance therapy to control the progression of renal failure although not sufficient for complete remission of AAV.

#2543 Complement receptor C5aR1 correlates with inflammatory responses driven by glomerular uPAR upregulation in renal vasculitides

Abstract Background and Aims Avacopan is a novel promising treatment for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) targeting the complement system by blocking C5a receptor C5aR1. We here pursued a transcriptome array-based approach to dissect molecular signatures associated with C5aR1 in renal vasculitis. Method C5aR1 mRNA expression levels (reporter ID: 210845_s_at, platform: Affymetrix Human Genome U133 Plus 2.0 Array, altCDF v10) were extracted from microdissected samples of renal vasculitis (glomerular: n = 23, tubulointerstitial: n = 21). Pathway analysis was performed for gene enrichment associated with PLAUR mRNA expression with a correlation threshold of ≥0.5 by using reactome (http://reactome.org), pathways with a predefined entities value of p≤0.001 were included. Results We here identified a predominant glomerular expression of C5aR1 in renal vasculitis as compared to the tubulointerstitial compartment (p < 0.0001). Furthermore, glomerular C5aR1 induction correlated with impaired kidney function (eGFR: 0.0193). Gene set enrichment identified various inflammatory signatures including neutrophil degranulation and innate immunity, and particularly enrichment of urokinase plasminogen activator receptor (uPAR). uPAR itself also correlated with impairment of kidney function in renal vasculitis and particularly active glomerular lesions (cellular crescents and necrosis, p < 0.0001). Conclusion The therapeutic implications of targeting uPAR in renal vasculitis are promising, and ongoing research endeavors are aimed at unraveling the complexities of uPAR as a potential diagnostic marker and therapeutic target for this challenging renal pathology. We here expand our current knowledge and link C5aR1 to inflammatory responses driven by glomerular uPAR upregulation in renal vasculitis.

#1681 Efficacy and safety of combined treatment with rituximab and low doses of cyclophosphamide for ANCA associated renal vasculitis

Abstract Background and Aims Current guidelines recommend the use of rituximab (RTX) or cyclophosphamide (CP) as induction treatment for ANCA-associated vasculitis (AAV) with renal involvement. Some authors have described the combination of CP and RTX in the treatment of severe AAV, and recently a regimen of 6 cycles of low-dose CP combined with RTX has been used with good results. The aim our study was to compare the efficacy and safety of combined treatment with even lower doses of intravenous CP (2-3 cycles) and RTX, compared to standard treatment with RTX. Method We conducted a retrospective study that included 14 patients with histologically confirmed AAV, treated with an induction treatment scheme of corticosteroids, RTX and 2-3 cycles of intravenous CP. A case-control analysis was performed with 16 patients who received only corticosteroids and RTX in the same period, matched by propensity score for age, creatinine at presentation and histological parameters (sclerosed glomeruli, epithelial crescents and normal glomeruli). We compared renal and overall survival, and complications from immunosuppression in both groups. Results At presentation, patients treated with the combined regimen had a mean age of 67 ± 12.1 years, a mean glomerular filtration rate estimated by CKD-EPI of 19.8 ± 11.1 ml/min/1.73 m2, proteinuria of 1.6 (0.81- 1.84) g/24 hours and initial BVAS score of 18.5 ± 6.9. 78.6% of the patients were anti-MPO positive and 21.4% were anti-PR3 positive. According to Berden's classification, 85.7% had a mixed variant, 7.1% crescentic and 7.1% sclerotic, in the renal biopsy. The mean dose of CP was 1445 ± 384 mg, and of RTX was 2g. 28.6% required dialysis at presentation, of which 75% recovered kidney function. The duration of steroid treatment was 8 (4.6-16.9) months. Remission rate at 6 months was 71.4%, and after a median follow-up of 20 (15-35) months, 92.9% had remitted. During follow-up, 50% had serious infections; and at the end, 7.1% progressed to end-stage chronic kidney disease (ESKD). 21.4% of the patients included ended up dying. In comparison with the control group, patients who received the combined treatment had a higher remission rate (92.9% vs. 75%), a lower relapse rate (15.4% vs. 35.7%), lower progression to ESKD (7.1% vs. 20%) and lower mortality (21.4% vs 37.5%), with no differences for serious infections. Conclusion The association of low doses of cyclophosphamide to rituximab induction treatment could improve the prognosis in patients with severe ANCA-associated renal vasculitis.

#1782 Clinicopathological study of renal limited pauci-immune vasculitis and its short-term outcome: a single centre observational study

Abstract Background and Aims Pauci immune crescentic glomerulonephritis, is a leading cause of RPGN. The majority of patients with PICGN have glomerular diseases as a part of a systemic small vessel vasculitis, a minority may present as renal-limited vasculitis. In north-east India, there are still no major studies in this group of patients. Therefore, our study involving north-east Indian population constitutes an effort to prospectively study the clinico-pathological feature of patients with PICGN and assess the short-term outcome. Method This single-centre, prospective, observational, study was conducted over 12 months at the Department of Nephrology, Gauhati Medical College. All renal biopsy-proven patients with pauci-immune renal vasculitis were included, excluding those with secondary vasculitis. Baseline characteristics and laboratory data were recorded, and disease activity was assessed using the Birmingham Vasculitis Activity Score. The ANCA tests were performed using a standardised essay for both indirect immunofluorescence assay and antigen-specific ELISA. The renal biopsy specimen obtained was evaluated by light microscopy and direct immunofluorescence. The sample size was calculated based on the prevalence of pauci-immune glomerulonephritis, and data were analysed using SPSS. Results The study involved 24 patients, predominantly females (70.83%), aged 14-65 years, presenting predominantly with pedal oedema and oliguria. Laboratory findings showed varying levels of haemoglobin, total count, platelet count, creatinine, and 24-hour urine protein. 50% of the patients were (MPO) positive, 33.3% were (PR3) positive while 16% were ANCA negative. Renal biopsy analysis showed a majority with mixed class according to the Berden classification. Treatment involved induction with Methylprednisolone and Cyclophosphamide, with dialysis administered to 58.3% of patients. At six months, 36.3% had a stable GFR, and 50% were on maintenance hemodialysis. Factors predicting renal loss included oliguria, dialysis at presentation, and fibrous/fibrocellular crescents. The best predictor of renal outcome was serum creatinine at presentation. Conclusion Pauci-immune CrGN is a severe disease affecting a wide age range. Early diagnosis and treatment initiation are crucial for better outcomes, including lower ESRD risk and relapse rates. Prognostic factors include baseline serum creatinine levels and fibrous crescents. Optimising treatment regimens may improves outcomes.

#1700 Clinical presentation and prognosis in ANCA-associated vasculitis with occupational exposure to silica: a monocentric retrospective study

Abstract Background and Aims Exposure to silica is associated with an increased risk of autoimmune diseases, including ANCA-associated vasculitis (AAV) [1–3]. It remains unclear whether silica exposure modifies clinical presentation of AAV, and it is not known whether it affects prognosis. The aim of this work is to address these questions. Method This is a retrospective, monocentric observational study comparing clinical and prognostic features between two groups of patients with ANCA-positive AAV: cases with a well-documented history of occupational exposure to silica (confirmed by industrial hygienists) and controls with no exposure. Each case was matched to 2 controls based on time of diagnosis (± 1 year relative to the case). Clinical features were compared across the two groups using Student's t test or chi-squared test, as appropriate. Clinical outcomes were compared across groups with the log-rank test and Cox proportional hazards regression. Results We identified 25 patients with AAV and a clear-cut history of occupational exposure to silica and 50 controls with no exposure, diagnosed between 2000 and 2023. Compared to controls, patients exposed to silica were more frequently males and smokers (Table). Average age at presentation was 66 ± 14 years and most patients had microscopic polyangiitis and MPO-ANCAs, with no significant differences according to silica exposure (Table). Patterns of organ involvement were also comparable across the two groups (Table). Renal vasculitis was present in almost all patients, probably reflecting a referral bias. Severity of renal impairment at diagnosis (Table) and evolution to end stage renal disease (Figure) were similar between exposed and unexposed individuals. There was a trend for lower survival in patients with exposure to silica (median survival from AAV diagnosis: 172 months in cases and 111 months in controls, log-rank test p = 0.065, Figure). In multivariate Cox regression, the risk of death was independently associated with age at diagnosis (HR 1.09 per year, 95% CI 1.04-1.14, p < 0.001) and not with silica exposure (HR 0.96, 95% CI 0.39-2.41, p = 0.936) or smoking history (HR 2.06, 95% CI 0.80-5.33, p = 0.135). Conclusion Patients with AAV and exposure to silica were more frequently males and smokers, likely reflecting socio-economic factors. We did not identify otherwise distinct clinical features in exposed patients, similarly to other Authors such as Hogan et al [2]. Exposure to silica did not seem to significantly affect renal prognosis or survival either, despite a trend in univariate analysis for higher mortality in individuals with silica exposure. The limited sample size and lack of quantification of silica exposure must be acknowledged and may have reduced statistical power.

#2700 Serum C3/C4 levels in renal antineutrophil cytoplasmic antibody-associated vasculitis: predictors of lung disease and worse prognosis

Abstract Background and Aims Complement activation, specially the alternative pathway, has been implicated in the development of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This was further corroborated with the efficacy of Avacopan, a selective C5a receptor inhibitor used as a corticosteroids reduction strategy in the treatment of AAV [1]. Low complement factor 3 (C3) levels without real hypocomplementemia are predictors of prognosis in AAV [2]. Low C4 levels have not yet been associated with worst outcomes. We aimed to evaluate the association between circulating C3 and C4 levels at diagnosis of AAV with clinical and biochemical features and with relevant outcomes: relapse, dialysis and death. Method This is a retrospective study including 63 patients with AAV with renal involvement followed between 2003-2023, with C3 and C4 levels measurements at diagnosis. Data was recorded from clinical registries. Patients were grouped according to the median C3 and/or C4 levels, as previously performed [2]. Groups were compared using the chi-square test for categorical variables and non-parametric tests for continuous variables. We created a logistic regression model for the outcomes, adjusting for covariates. Results Mean age at diagnosis was 61.1 ± 13.4 years old and most patients had ANCA MPO specificity (69.8%, n = 44). Only 3 patients had low C3 levels (< 83 mg/dL) and C4 hypocomplementemia (<12 mg/dL) was present in other 3 patients. Median C3 levels were 127.5 mg/dL (107.3-139.0) and median C4 levels were 29.5 mg/dL (22.0-35.0). Groups were defined according to these values: low C3 levels (C3 <127.5 mg/dL, n = 31), low C4 levels (C4 <29.5 mg/dL, n = 31) and low C3 and/or C4 levels, when either of these conditions were met (n = 40). There was a positive correlation between C3 and C4 levels (r = 0.57, p < 0.001). Patients with low C3 levels had more frequent lung involvement than patients with higher C3 levels (71% vs 31.3%, p = 002), as well as alveolar hemorrhage (38.7% vs 12.9%, p = 0.020). Regarding the outcomes, there was a tendency for more patients requiring acute dialysis (first month) and progressing to dialysis during follow-up in the low C3 subgroup. Relapse and death rates were similar between the two groups. Low C4 levels were associated with older age (75 ± 11.8 vs 67.5 ± 13.7 years, p = 0.043), higher relapse rates (50% vs 25.8%, p = 0.05) and faster progression to dialysis (1.0 (1.0-5.0) vs 9.5 (1.8-54) months, p = 0.034). When combining low C3 and/or C4 levels, lung involvement was again more frequent in patients with lower complement levels (62.5% vs 30.4%, p = 0.014). Time to dialysis was lower and relapse rates were higher in the subgroup with low complement levels, but not statistically significant. No association with death was found. Interestingly, acute dialysis requirement was more prevalent in the low C3/C4 levels subgroup (32.5% vs 8.7%, p = 0.033). After adjustment for baseline renal function, low C3/C4 levels showed an increase of 7 times the odds of a patient requiring acute dialysis (OR 6.98; 95% CI 1,196-40,839, p = 0.031, Table 1). Low C3/C4 levels independently predicted the odds of lung disease in AAV (OR = 5,069; 95% CI 1,475-17,612 p = 0.010, Table 2). Conclusion Complement activation in AAV has been previously associated to renal outcomes, but our results also highlight a possible role of complement in the pathophysiology of lung disease. Low C4 levels were associated with higher relapse rates and faster progression to dialysis, revealing that C4 activation impacts outcomes in AAV and that both classic and alternative complement pathways are involved. Combining low C3 and/or C4 levels identified patients at higher risk of acute dialysis requirement, independently of renal function at admission. Further insights in the specific effects of C3/C4 are needed to stipulate the value of monitoring and targeting complement factors in AAV.

#401 Cardiovascular risk evaluation in lupus nephritis and ANCA-associated vasculitis

Abstract Background and Aims Individuals with lupus nephritis (LN) and renal ANCA-associated vasculitis (AAV) have amplified cardiovascular risks. Early recognition and intervention for metabolic disease may mitigate cardiovascular risk. We aimed to evaluate the prevalence of cardiovascular metabolic risk evaluation among adults with kidney disease due to LN and AAV treated with immunosuppressants. Method Retrospective cohort study of 219 patients with kidney LN (n = 175) and AAV (n = 44) diagnosed between November 2015 and December 2022. The outcomes were the prevalence of cardiovascular metabolic risk evaluation (HbA1c, fasting glucose and lipid) during the first two years of treatment. Results The median age was 48.6 (33.3, 60.9) years. Table 1 showed that the AAV group had lower eGFR and higher prevalence of diabetes mellitus, hypertension, and hyperlipidemia. Glycemic evaluation was more frequent during the first year than the second year (81.0% versus 61.2%, p < 0.001) for the cohort, as well as the LN (79.2% versus 61.7%, p < 0.001) and AAV groups (88.4% versus 58.8%, p = 0.003). Lipid evaluation was more frequent during the first year than the second year for the cohort (60.5% versus 50.3%, p = 0.04) and for AAV (81.4% versus 47.1%, p = 0004), but not the LN group (55.1% versus 51.0%, p = 0.52). Conclusion Cardiovascular metabolic risk evaluation during lupus nephritis (LN) and ANCA-associated vasculitis (AAV) long-term follow-up should be optimized.

#2291 ANCA negative vasculitis—the unmet need within small vessel vasculitis

Abstract Background and Aims ANCA negative small vessel vasculitis with renal involvement has been described in a number of cohorts. Though comprehensive studies comparing these individuals to ANCA positive patients are lacking and they are routinely excluded from clinical trials. Whilst the numbers are smaller than those with ANCA positivity, they still make up a large proportion of small vessel vasculitidies (Fig. 1). The absence of detectable circulating ANCA is thought to indicate a distinct spectrum of the disease. There remains unanswered questions regarding the pathophysiology, diagnosis and management of patients with seronegative AAGN. We present data from Croatian referral center. Method Study included 106 AAV patients with biopsy proven renal involvement in the period from 2007-2017. Category variables were analysed with Fisher Exact test and continuous with Kruskal-Wallis test. Statistical difference was then analysed post hoc with Chi-square test. Kaplan Meyer survival analysis and multivariate Cox proportional hazard regression analysis were used to explore difference between clinical phenotypes and finding significant predictors regarding outcomes which were defined as combined outcome end-stage renal disease and death (ESRDD), ESRD alone, the death outcome alone and relapse rate. Results 106 AAV patients with renal involvement were included: 66 (61.1%) MPA, 20 (18.5%) GPA, 20 (18.5%) RLV. 14 (13%) were PR3-ANCA positive, 57 (52.8%) MPO ANCA positive, 5 (4.6%) PR3-ANCA+MPO-ANCA and 32 (29.6%) ANCA negative patients. ANCA negative patients were comparatively younger (p = 0.02) and presented with more renal limited vasculitis (RLV; p < 0.001), lower BVAS (p = 0.003) and lower CRP (p = 0.001). ANCA negative patients usually presented with nephrotic syndrome compared to positive ones which presented with rapid progressive nephritic syndrome or acute nephritic syndrome (p = 0.027). 24-hour proteinuria levels were higher in ANCA negative group (p = 0.003). Though statistical difference was not reached, there was tendency for ANCA negatives to receive less plasmapheresis (p = 0.074). Histologically there were no differences between ANCA positive and ANCA-negative patients. On sub analysis ANCA negatives versus individual seropositive groups, there was tendency that ANCA negatives and MPO-ANCA patients had lower percentage of glomerular crescents (p = 0.092) but more acute tubular damage (p = 0.087). There were no differences in clinical outcomes between the groups. Conclusion ANCA negative vasculitis form a large proportion of small vessel vasculitidies and present with different clinical laboratory and histological (renal) characteristics than ANCA positive ones. More often than not disease seems to be renal limited and patients tend to be younger. Due to the rarity of the disease, there remains unanswered questions regarding the pathophysiology, diagnosis and management of these patients. This study highlights noteworthy distinctions between the two groups. Whether these differences warrant adjustments in treatment algorithms or a reconsideration of the classification of small vessel vasculitis remains to be determined. Further investigation into the pathogenetic mechanisms of seronegative AAVs is essential.

#211 Low albumin levels are associated with intrarenal complement C4d deposits in critically ill patients with ANCA-associated renal vasculitides

Abstract Background and Aims Despite serum albumin levels being predictive for clinical outcome in ANCA-associated renal vasculitis, implications providing a direct link between low serum albumin levels and intrarenal lesions remain elusive. Therefore, we here aimed to systematically assess the clinical relevance of low albumin levels and scrutinize clinicopathological correlations to expand our current knowledge. Method We here retrospectively enrolled biopsy-proven cases of ANCA-associated renal vasculitis between 2015 till 2020 in a single-center observational study. Survival-curve analyses on long-term renal survival and short-term clinical recovery were performed. Correlative analyses between serum albumin levels, laboratory parameters, proteinuria levels, and histopathological lesions including tubulointerstitial immune cell infiltrates, lesions analogous to the Banff score and intrarenal complement deposition of C3c and C4d were performed. Results We here show that hypoalbuminemia below the median of 2.4 g/dL impairs long-term renal survival especially in MPO-positive ANCA-associated renal vasculitis (p = 0.006, HR: 5.0, 95% CI: 1.2-21.5), while short-term clinical recovery particularly in critically ill patients is negatively affected by low serum albumin levels (p = 0.0082, HR: 3.6, 95% CI: 1.1-11.7). Low albumin levels are associated with the urinary marker of tubular damage in the total cohort (β = −0.5, p = 0.01), PR3-ANCA (β = −0.5, p = 0.04) and MPO-ANCA (p = 0.002, β = −0.8), but not in critically ill patients (β = −0.5, p = 0.07) implying hypoalbuminemia to occur by extrarenal causation in the state of critical illness. We identified plasmacytic infiltrates to correlate with low albumin levels in the total cohort (β = −0.6, p = 0.004) and in the subgroup of critically ill patients (β = −0.7, p = 0.005). Banff-scored interstitial inflammation (i) was further observed to inversely correlate with albumin levels (β = −0.7, p = 0.02). Intrarenal C4d deposition showed a significant correlation with low serum albumin levels in the glomerular tuft (β = −0.4, p = 0.04) and in interstitial arteries (β = −0.7, p = 0.01). Conclusion In conclusion, long-term renal outcome is significantly affected by low serum albumin levels especially in the setting of MPO-ANCA seropositivity. By contrast, short-term recovery was predicted by low albumin levels in critically ill patients with ANCA-associated renal vasculitis. We here provide evidence that low levels of serum albumin might directly affect tubulointerstitial inflammation as reflected by plasmacytic immune-cell infiltration, and intrarenal C4d complement deposition in ANCA-associated renal vasculitis.

#777 Renal recovery for patients with ANCA-associated vasculitis and low eGFR in a Spanish cohort

Abstract Background and Aims Renal failure secondary to ANCA-associated vasculitis (AAV) represents a clinical and therapeutic challenge [1]. Fifteen percent to 38% of the patients develop end-stage kidney disease within 5 years, and once patients need dialysis, 29% to 82% die or remain on dialysis 3 to 6 months after its initiation [2]. Therefore, effectively managing renal vasculitis and preventing patients from reaching dialysis have important consequences [2]. A post hoc analysis of ADVOCATE trial examined outcomes in a patient subgroup with severe renal insufficiency (i.e., estimated glomerular filtration rate (eGFR) ≤20 ml/min per 1.73 m2) at enrollment into the trial, and observed an average eGFR increase of 16.1 and 7.7 ml/min per 1.73 m2 in the avacopan and prednisone groups, respectively (P = 0,003) [2]. This study aimed to compare the average eGFR increase in our cohort of AAV with severely reduced GFR (<20 ml/min) treated with different induction treatment schemes. Method We performed a retrospective study which included 19 patients with the diagnosis of AAV and severe renal insufficiency at onset with eGFR between 15 to 20 ml/min per 1.73 m2. We analyzed the eGFR increase after 12 months of follow-up, according to the induction treatment scheme: cyclophosphamide, rituximab, a combination of cyclophosphamide and rituximab and other (prednisone alone, prednisone with plasma exchange or prednisone with mycophenolic acid). We compared our results to those obtained in the avacopan and prednisone groups in the ADVOCATE trial. Results In the subgroup of eGFR between 15 to 30 ml/min per 1.73 m2, patients had at enrollment a mean eGFR of 21 ± 5 ml/min per 1.73 m2 and after 12 months of follow-up the mean eGFR was 41 ± 23 ml/min per 1.73 m2 with an increase of 20 ± 23 ml/min per 1.73 m2. In the subgroup of eGFR between 15 to 20 ml/min per 1.73 m2, patients had at enrollment a mean eGFR of 17 ± 2 ml/min per 1.73 m2 and after 12 months of follow-up, the mean eGFR was 35 ± 20 ml/min per 1.73 m2 with an increase of 18 ± 21 ml/min per 1.73 m2. After 12 months of follow-up, the mean increase of eGFR was 18, 17, 10 and 23 ml/min per 1.73 m2 in the cyclophosphamide, rituximab, a combination of cyclophosphamide and rituximab and other groups, respectively. We compared our results with the post hoc analysis of the ADVOCATE trial in Table 1 and our results are similar to the avacopan group and better than the prednisone group (p < 0.05). Conclusion In our cohort of eGFR between 15 to 20 ml/min per 1.73 m2 at enrollment, the mean increase in eGFR after 12 months of follow-up was similar to the avacopan group and greater than the prednisone group in the ADVOCATE trial.

#3108 Rituximab in adult-onset IgA vasculitis

Abstract Background and Aims Adult-onset IgA Vasculitis (IgAV) is poorly responsive to glucocorticoids (GC) and conventional immunosuppressive therapies, such as cyclophosphamide. Rituximab has been successfully used in a few cases and may represent a safer and potentially more effective option [1]. Crescentic IgA Nephropathy (cIgAN), a rare entity that shares features of renal vasculitis with IgAV, is also frequently refractory to cyclophosphamide, while response to rituximab is unknown. We investigated outcomes after rituximab in a multicentre European cohort of adult-onset IgAV and cIgAN. Method We screened clinical records of patients followed at 18 European consorted centres who were ≥18 years old at the onset of IgAV and received ≥1 rituximab dose. Furthermore, we identified patients with cIgAN (≥25% crescentic glomeruli and rapidly progressive glomerulonephritis), who were treated with rituximab. Remission was defined as Birmingham Vasculitis Activity Score (BVAS) <3 at month 6 after rituximab and renal response as stable or improved eGFR and ≥50% proteinuria reduction. Relapse was defined as an increase in BVAS requiring a change in immunosuppressive therapy. Outcomes of IgAV with severe nephritis (eGFR <60 mL/min) were compared with those of cIgAN. Results We included 61 patients with IgAV and 15 with cIgAN (Table). Rituximab was administered as initial therapy in 23/61 (38%) patients with IgAV and 13/15 with cIgAN (87%), while the remainder had refractory or relapsing disease. Active skin involvement was present in 49 patients (80%) and nephritis in 55 patients (90%) with IgAV at the time of starting rituximab. This was given alone in 13/61 (21%) or combined with GC in 48 (79%) patients with IgAV and in all those with cIgAN. Furthermore, cyclophosphamide was used in 15% of patients with IgAV and 40% of those with cIgAN. Remission at 6 months was achieved by 52 (85%) patients with IgAV and 12/13 (92%) of those treated with rituximab alone. A renal response was observed among 49/55 (89%) of those with nephritis. Patients with IgAV and severe nephritis had similar eGFR to those with cIgAN at the time of starting rituximab, but the latter had lower rate of remission and a higher frequency of kidney failure. A relapse occurred in 15/52 patients (29%) who achieved remission a median of 13 months (10-15) after rituximab. Eight patients resumed rituximab and achieved again remission. Conclusion Rituximab alone or in combination with GC and immunosuppressants appeared to achieve a high rate of remission in this cohort of adult-onset IgAV. Renal response among those with severe nephritis was also good, while this was worse among patients with cIgAN, suggesting substantial differences among these conditions despite similar histological appearances.

Overlap syndrome of systemic sclerosis with antineutrophil cytoplasmic antibody-associated vasculitis according to 2022 ACR/EULAR criteria.

This study applied the 2022 American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) criteria for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) to patients with systemic sclerosis (SSc) and investigated the frequency of overlap syndrome of SSc and AAV (SSc-AAV-OS). Among the 232 patients diagnosed with SSc, 105 with signs suggestive of small- or medium-vessel vasculitis, which were defined as the present of interstitial lung disease (ILD), peripheral neuropathy, or suspected renal vasculitis, were included in this study and analyzed. Among the 105 SSc patients, the detection rate of ANCA was 19.0%. When the 2022 ACR/EULAR criteria were applied, the frequency of SSc-AAV-OS was 20.0%, which was much higher than 1.7% reported with previous criteria for AAV. ANCA positivity contributed to the reclassification of SSc-AAV-OS more than ANCA negativity in SSc patients with signs suggestive of small- or medium-vessel vasculitis. The frequency of SSc-AAV-OS in SSc patients with signs suggestive of small- or medium-vessel vasculitis at diagnosis was 20.0%. Therefore, we suggest that physicians should perform ANCA tests in SSc patients exhibiting signs suggestive of small- or medium-vessel vasculitis and apply the new criteria for AAV.