Genetics of ANCA-associated vasculitis: role in pathogenesis, classification and management

Differences in phenotypes, treatments, and outcomes of ANCA-associated vasculitis across Europe, Japan and the USA in 2020

OBJECTIVES

To clarify the differences in clinical phenotypes, therapeutic patterns, and outcomes of patients with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) across geographic regions using a multinational cohort.

METHODS

Data were collected from patients with newly diagnosed or relapsing GPA or MPA in Europe, Japan and the USA from January to July 2020. The composite outcome of kidney failure and/or death within 52 weeks after treatment was evaluated, and the hazard ratios across the regions were estimated using the Cox proportional hazard model. Heterogeneities of the effects were investigated via thorough subgroup analyses.

RESULTS

Among the 254 eligible patients (Europe, 137; Japan, 73; USA, 44), those in Japan were older and had higher proportions of MPO-ANCA positivity and lung involvement compared with Europe and the USA. The estimated glomerular filtration rate at diagnosis varied across regions, with the highest dialysis requirement in the USA. Cyclophosphamide and rituximab use were, respectively, 57% and 63% in Europe, 29% and 40% in Japan, and 34% and 86% in the USA. Within 52 weeks, 8%, 10% and 18% developed kidney failure, while 9%, 7% and 7% died in Europe, Japan, and the USA, respectively; and the composite outcome occurred in 15%, 14% and 23% of patients. The hazard ratios for kidney failure and/or death were comparable across regions; however, they varied among certain subgroups.

CONCLUSIONS

Although the kidney failure-free survival was comparable across continents, regional differences existed in clinical phenotypes and therapeutic patterns.

IgG4-related disease and other fibro-inflammatory conditions

IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder usually characterized by multi-organ involvement. Its pathogenesis is complex and involves genetic and environmental factors, while immune responses usually mediate organ damage and promote fibrosis, which is a key feature of the disease. IgG4 responses, however, are not exclusive to IgG4-RD and can be encountered in other diseases with phenotypes that partially overlap that of IgG4-RD. Although IgG4-RD has clinical and histological hallmarks, the lack of validated diagnostic criteria often makes the diagnosis challenging, requiring a multi-dimensional approach that integrates clinical, radiological and serological data. The present Review covers recent advances in the understanding of disease drivers and its clinical phenotypes, mainly focusing on the differential diagnosis with potential IgG4-RD mimickers, namely histiocytoses, lymphoproliferative disorders, systemic vasculitides and other immune-mediated conditions. The Review also provides a schematic approach to IgG4-RD treatment, including a brief overview of glucocorticoid-sparing agents and emerging therapies, from B cell-depleting monoclonal antibodies to cytokine-targeting drugs, the majority of which are currently under investigation in randomized clinical trials.

Dupilumab for refractory chronic rhinosinusitis in eosinophilic granulomatosis with polyangiitis

OBJECTIVES

Eosinophilic granulomatosis with polyangiitis (EGPA) is frequently associated with refractory chronic rhinosinusitis with nasal polyps (CRSwNP), despite current treatments. Dupilumab demonstrated efficacy in the treatment of severe and uncontrolled CRSwNP, with improvements in patient-reported outcome measures (PROMs) and in objective measurements. This study aims to evaluate efficacy and safety of dupilumab in refractory CRSwNP in EGPA patients.

METHODS

A prospective observational study was conducted on EGPA patients treated with dupilumab between 2021 and 2023. Patients in a phase of prolonged remission of vasculitis manifestations but still experiencing active CRSwNP were included. Clinical, biological, and rhinologic evaluations were performed, alongside with PROMs and nasal cytology. Complete response was defined by BVAS = 0 and prednisone dose ≤4 mg/day, while partial response by BVAS = 0 and prednisone dose >4 mg/day.

RESULTS

Nine EGPA patients were included. After 3 months, 55.6% achieved complete response, increasing to 83.3% at 12 months. Nasal symptoms and patient-reported outcomes improved significantly, with sustained efficacy over 12 months. An improvement in quality of life was also observed, with a significant reduction in the AAV-PRO score. Nasal cytology revealed reductions in eosinophils and neutrophils counts. Adverse events occurred in 44.4%, including hypereosinophilia in two cases, which led to dupilumab discontinuation.

CONCLUSION

Dupilumab is an effective treatment option for severe and refractory ENT manifestations in EGPA, as it improves symptoms, reduces inflammation, and leads to better a quality of life. However, careful patient selection and monitoring are necessary to minimize adverse events and optimize outcomes.

The emerging concept of ANCA-associated vasculitis related to inborn errors of immunity

ANCA-associated vasculitis (AAV) is a group of rare small vessels vasculitis that preferentially affect the kidneys, lungs and upper airways. Although the detailed pathophysiology remains unclear, genetic background has been shown to play a role in sporadic forms of AAV. The discovery of these susceptibility genes (and associated biological pathways) involved in AAV have shaped the current understanding of AAV pathophysiology. In addition to common genetic polymorphisms, specific rare inborn errors of immunity (IEI) have been described with a high frequency of ANCA (antineutrophil cytoplasmic antibodies) positivity and vasculitis features in young individuals (in addition to other manifestations). A systematic literature search revealed that patients with pathogenic variants in COPA, STING1, DNASE1L3, and PIK3CD are at increased risk of developing ANCA and AAV features, including alveolar hemorrhage, interstitial lung disease, pauciimmune glomerulonephritis, and upper airways involvement (septum perforation, saddle-nose deformity, chronic nasal/sinuses ulceration). Some of these IEI may also present with a mixed phenotype and/or auto-antibodies profile associating features of AAV and other autoimmune diseases (in particular systemic lupus erythematosus). Notably, a proportion of reports and series lack serological (ANCA specificity and titers) and/or histopathological data, making challenging to assess the likelihood for ANCA pathogenicity in some patients with IEI (as opposed to unspecific signs of biologic autoimmunity). This point is nonetheless essential to make appropriate therapeutic decisions. In addition, since most of the genes mentioned above are involved in the type 1 interferon signaling, the role of this pathway in AAV etiopathogenesis deserves further investigation. In this review, we will describe these IEI, their overlap with sporadic AAV, and their evocative features. Next, we will discuss how these monogenic conditions might inform our general understanding of AAV pathophysiology. We also propose some directions for future research in order to better define the link between ANCA and IEI. Finally, we will consider how making the diagnosis of an IEI in a patient with AAV features might impact individual management.

18F-FDG PET/CT Imaging of Eosinophilic Granulomatosis With Polyangiitis

A 29-year-old woman presented with asthma, fever, generalized rash, and numbness in the ring and pinky fingers of her right hand. Laboratory studies showed significant increases in blood eosinophils, C-reactive protein, and IgE, but ANCA (antineutrophil cytoplasmic antibodies) were negative. The 18F-FDG PET/CT suggests scattered, segmented FDG uptake around small and medium vessels throughout the body. After comprehensive analysis, the patient's final clinical diagnosis was eosinophilic granulomatous vasculitis.

Relapses and serious adverse events during rituximab maintenance therapy in ANCA-associated vasculitis: a multicentre retrospective study

OBJECTIVES

There are limited real-life data regarding the efficacy and safety of rituximab (RTX) as a remission maintenance agent in microscopic polyangiitis (MPA) and granulomatosis-with-polyangiitis (GPA). We aimed to estimate the incidence and risk factors for relapses, as well for serious adverse events (SAEs) in MPA/GPA patients during RTX maintenance.

METHODS

A retrospective cohort of newly diagnosed/relapsing GPA/MPA patients who received RTX maintenance (≥1 RTX cycle, ≥6 months follow-up) following complete remission (BVAS version-3 = 0 plus prednisolone ≤7.5 mg/day) with induction regimens. SAEs included serious infections, COronaVIrus-Disease 2019 (COVID-19)-associated hospitalizations, deaths, cardiovascular events, malignancies and hypogammaglobulinemia. The incidence rates (IRs) and relapse-free survival were estimated through Kaplan-Meier plots. Cox regression was conducted to investigate factors associated with the time-to-relapse.

RESULTS

A total of 101 patients were included: 48% females, 69% GPA, 53% newly diagnosed, median age 63 years. During follow-up (294.5 patient-years, median: 3 RTX cycles), 30 relapses (57% major) occurred among 24 patients (24%, IR 10.2/100 patient-years). Kidney involvement (adjusted hazard ratio/aHR: 0.20; 95% CI: 0.06-0.74, P = 0.016), prior induction with RTX plus CYC (vs RTX monotherapy: aHR = 0.02; 95% CI: 0.001-0.43, P = 0.012) and shorter time interval until complete remission (aHR = 1.07; 95% CI: 1.01-1.14, P = 0.023) were associated with decreased relapse risk. We recorded 17 serious infections (IR 5.8/100 patient-years), 11 COVID-19-associated hospitalizations (IR 3.7/100 patient-years), 4 malignancies (IR 1.4/100 patient-years), 6 cardiovascular events (IR 2/100 patient-years) and 10 deaths (IR 3.4/100 patient-years).

CONCLUSION

In this real-world study, relapses during RTX maintenance occurred in approximately 1 out of 4 patients. Kidney involvement, induction with RTX plus CYC, and earlier achievement of complete remission were associated with lower relapse risk. The serious infections rate was consistent with previous reports, whereas an increased rate of COVID-19-associated hospitalizations was observed.

Role of 18F-FDG PET/CT in assessing systemic involvement in ANCA-associated vasculitis

The utilization of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has become a pivotal tool in diagnosing anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis, especially when the disease presents with neurological symptoms as the initial indicator. This advanced imaging technique was applied in a 68-year-old female patient who presented with recurrent limb weakness and intermittent blindness, symptoms that warranted thorough investigation due to their complexity and severity. The 18F-FDG PET/CT revealed significant radiotracer uptake in the kidneys, spleen, skeletal muscles, and right axillary lymph nodes, indicative of systemic involvement-a hallmark of ANCA-associated vasculitis (AAV) that can lead to multi-organ damage if not promptly managed. Complementary electromyography (EMG) identified multiple instances of peripheral nerve damage, adding further evidence to the diagnosis. This case underscores the intricate interplay between clinical symptoms, imaging findings, and laboratory results, all crucial in accurately diagnosing AAV. The findings highlight that 18F-FDG PET/CT not only facilitates early detection of neurogenic skeletal muscle damage and occult lesions, but also aids in precise disease classification, essential for guiding treatment strategies. The ability of this imaging modality to provide early warnings of major organ involvement offers clinicians a valuable opportunity to intervene before irreversible damage occurs, ultimately improving the accuracy of diagnosis and contributing to more effective management and outcomes for patients with this complex autoimmune disorder.

Strawberry gingivitis as an initial presentation of granulomatosis with polyangiitis in an older adult

OBJECTIVE

To describe a rare case of granulomatosis with polyangiitis (GPA) in an older adult in light of the existing literature.

BACKGROUND

GPA is a potentially life-threatening multisystem necrotising vasculitis, characterised by a spectrum of oral mucosal lesions that present diagnostic challenges.

MATERIALS AND METHODS

A 76-year-old female patient presented with asymptomatic granular and haemorrhage swelling ("strawberry" gingivitis) affecting the upper and lower anterior and posterior gingivae. Cytoplasmic antineutrophil cytoplasmic antibody (ANCA) was positive. Concurrent kidney lesions were diagnosed.

RESULTS

Histopathological examination revealed a pseudoepitheliomatous proliferation with perivascular inflammation and a dense eosinophilic infiltrate. After a 5-year follow-up, the patient showed no signs of recurrence. A literature review performed using PubMed, Web of Science and Scopus identified 22 documented cases of GPA-related oral lesions in older adults, with equal sex distribution and 63.6% occurring in the seventh decade of life.

CONCLUSION

Early recognition and diagnosis of "strawberry" gingivitis in older adults with GPA are crucial, as these oral manifestations may be the initial presentation of the disease.

The effects of plasma exchange and glucocorticoids on early kidney function among patients with ANCA-associated vasculitis in the PEXIVAS trial

Therapeutic plasma exchange (PLEX) is an adjunctive treatment for patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and kidney involvement. Little is known about the effect of PLEX on early changes in kidney function. This post-hoc analysis of the PEXIVAS trial investigated the effects of PLEX on changes in kidney function within 12 months. PEXIVAS was a randomized controlled trial recruiting 691 patients with ANCA-associated glomerulonephritis, of whom 349 underwent PLEX and 342 received no-PLEX. The primary outcomes of this post hoc study of PEXIVAS were change in estimated glomerular filtration rate (eGFR) from baseline and recovery of kidney function (defined as eGFR increase of 15ml/min/1.73m2 or more). Baseline eGFR was 21.7 ± 20.3 and 20.6 ± 18.7 ml/min/1.73m2 in the PLEX and no-PLEX groups, respectively. Mean improvements in eGFR at weeks two, four, and eight after initiation of therapy were greater for the PLEX vs. the no-PLEX groups. The greatest significant difference in recovery of kidney function in the PLEX compared to the no-PLEX groups was at week four (relative risk (RR): 1.41; 95% confidence interval:1.09-1.82). Increased eGFR or recovery of kidney function at week four were significantly associated with lower risk for end-stage kidney disease at week 52 (RR: 0.96: 0.95-0.97, and RR: 0.29: 0.16-0.52; respectively). Neither changes in eGFR nor recovery of kidney function differed by reduced- compared to standard-dose glucocorticoid group. Overall, our study indicates that PLEX improves early kidney function in patients with ANCA-associated glomerulonephritis.

A 28-Year-Old Man with Stridor and Dyspnea

Background: Tracheobronchial stenosis is a significant complication in granulomatosis with polyangiitis (GPA), a systemic vasculitis that primarily affects the upper respiratory tract, kidneys, and lungs. The involvement of the tracheobronchial tree in GPA leads to airway narrowing, which can result in severe respiratory symptoms and increased morbidity, often requiring prompt diagnosis and management to prevent life-threatening airway obstruction. Method: We present the case of a 28-year-old male with mild exertional dyspnea, stridor, and retropharyngeal sputum. Clinical investigations revealed subglottic and bronchial concentric stenosis with granulomatous inflammation. A diagnosis of granulomatosis with polyangiitis (GPA) with isolated tracheobronchial stenosis (TBS) was confirmed. Results: Given the severity of airway obstruction, multidisciplinary management was initiated, combining rigid bronchoscopy with systemic immunosuppressive therapy. Post-intervention follow-up demonstrated significant airway improvement and maintained remission after two years. Conclusions: This case highlights TBS as a potentially debilitating GPA manifestation requiring a combination of systemic and endoscopic therapies. Further studies are needed to optimize therapeutic approaches and improve outcomes in GPA-associated TBS.

Cardiac involvement in eosinophilic granulomatosis with polyangiitis: acute eosinophilic myocarditis and chronic inflammatory cardiomyopathy

OBJECTIVES

Currently, cardiac involvement is used to describe all eosinophilic granulomatosis with polyangiitis (EGPA) cardiac problems. However, heterogeneity exists among them. We aimed to depict the disease spectrum of EGPA cardiac involvement and identify the high-risk population.

METHODS

We included EGPA patients hospitalized in our centre from 2012 to 2023 and in public databases. Based on the cardiac enzymes, cardiac MRI and endomyocardial biopsy results, the patients were divided into three groups: eosinophilic myocarditis (EGPA-EM), chronic inflammatory cardiomyopathy (EGPA-ICM) and EGPA-Control. Their clinical, laboratory, imaging results and prognoses were collected and compared.

RESULTS

A total of 193 EGPA patients were included, 118 with cardiac involvement (74 EGPA-EM, 44 EGPA-ICM) and 75 control. Among EGPA-Control, EGPA-ICM and EGPA-EM, eosinophil increased (6.12/8.71/10.42 × 109/l, P < 0.01), ANCA positivity decreased (41.33/31.82/14.86%, P < 0.01) and lung involvement was reduced (73.33/72.73/43.24%, P = 0.02). In EGPA-EM, cardiac troponin was further elevated (0.27 vs 6.00 ng/ml, P < 0.01), ejection fractions decreased (57.79 vs 33.20%, P < 0.01) while more ST-T abnormality was observed (41.89 vs 20.45%, P = 0.02). The prognosis of EGPA-EM was significantly worse, with a 14.86% death rate and 2-year event-free survival rate below 50%. Furthermore, we proposed a LATE-EAST diagnostic score (7 items, 9 points) to discriminate EGPA-EM from EGPA-ICM using 4 points as threshold [area under the receiver operating characteristic curve 0.85 (95% CI 0.78-0.92), sensitivity 0.78, specificity 0.86].

CONCLUSIONS

We first proposed different subtypes of cardiac involvement in EGPA. Identification and treatment of EGPA-EM needs improvement. LATE-EAST score could recognize the high-risk EGPA-EM effectively. Multi-disciplinary treatment is warranted, immunosuppressive therapy should be given in a timely manner and anti-IL-5 antibodies should be be tested in trials.

Gastrointestinal lesions of eosinophilic granulomatosis with polyangiitis: a prediction model and clinical patterns

OBJECTIVE

Severe gastrointestinal lesions are associated with a poor prognosis in eosinophilic granulomatosis with polyangiitis (EGPA). The goal of this study was to develop an effective predictive model for gastrointestinal lesions and to examine clinical patterns, associated factors, treatment, and outcomes of gastrointestinal lesions in EGPA.

METHODS

We retrospectively enrolled 165 EGPA patients. The independent associated factors were analyzed using multivariate logistic regression. A nomogram was conducted to quantify the predictive factors. The correlation between different organ lesions was calculated to explore the clinical patterns.

RESULTS

A total of 52 patients had gastrointestinal lesions, and 22 developed severe disorders. Common manifestations included abdominal pain (78%), diarrhea (40.4%), and nausea and/or vomiting (32.7%). Severe gastrointestinal lesions included hemorrhage (26.9%), ulcers (17.3%), obstruction (9.6%), and pancreatitis (5.8%). Eosinophilic tissue infiltration, weight loss, and myalgia were independently associated with gastrointestinal involvement. Patients with severe gastrointestinal lesions had a shorter duration from initial symptoms to EGPA diagnosis, less frequent asthma, and ear-nose-throat involvement, and were more likely to receive methylprednisolone pulse. Weight loss, central nervous system involvement, myalgia, and eosinophilic tissue infiltration were retained in the nomogram. An eosinophil ratio of over 19.2% identified gastrointestinal lesions. Significantly more patients with gastrointestinal involvement had a Five Factor Score ≥ 2. Five well-defined clinical models were identified, including the brain-gut pattern.

CONCLUSIONS

Severe gastrointestinal lesions are common in EGPA and early detection is critical. Eosinophils are an important factor associated with gastrointestinal involvement of EGPA. We developed a model to predict the risk of gastrointestinal lesions. The brain-gut pattern might deserve further investigation in EGPA.

Influence of sodium ferulate on neutrophil extracellular traps-platelet activation-mediated endothelial dysfunction in immune small vasculitis

Objective

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune disease that is challenging to treat. This study aimed to identify the effect of sodium ferulate on endothelial dysfunction mediated by neutrophil extracellular trap (NET)-platelet activation in AAV to provide potential strategies for AAV treatment.

Material and Methods

An animal model of myeloperoxidase (MPO)-AAV passive immune vasculitis was established using anti-MPO immunoglobulin G and Rag2 knockout mice. The efficacy and mechanism of action of sodium ferulate in AAV were explored in cultured and isolated endothelial progenitor cells (EPCs), and messenger ribonucleic acid gene expression, relative protein expression, and protein fluorescence intensity were determined through quantitative polymerase chain reaction, Western blotting, and immunofluorescence, respectively. Serum antibody concentrations were determined by enzyme-linked immunosorbent assay, and flow cytometry was used in determining the expression levels of platelet-selectin (CD62p) and procaspase-activating compound-1 (PAC-1) on the surfaces of the platelets. The EPCs' ultramicroscopic structure was observed through transmission electron microscopy.

Results

The expression levels of ANCA, histone H3 citrullinated, and MPO protein fluorescence intensity in MPO-AAV mice were inhibited by sodium ferulate, and the expression levels of CD62p and PAC-1 on the cell surface were reduced. The relative expression levels of β-trace protein (β-TG), soluble thrombomodulin, inducible nitric oxide synthase (iNOS), and tumor necrosis factor α decreased. We found that sodium ferulate inhibited NETs' free DNA and mitigated damage in EPCs. In addition, relative expression levels of von Willebrand Factor, β-TG, and iNOS and serum concentrations of PAC-1, β-TG, and iNOS were inhibited.

Conclusion

Sodium ferulate can treat AAV by inhibiting NET release and platelet activation and reducing endothelial cell damage.

The Pathogenic Role of Expanded CD8⁺CD28null Angiogenic T Cells in ANCA-Associated Vasculitis

Objectives: Angiogenic T cells (Tang) are crucial in promoting angiogenesis, with the loss of CD28 serving as a marker for highly differentiated and senescent T cells. This study aims to investigate the characteristics and potential roles of CD8+CD28null Tang in patients with ANCA-associated vasculitis (AAV). Methods: A cohort of AAV patients and matched healthy controls (HCs) were analyzed. Flow cytometry was used to assess the profiles of circulating CD8+CD28null Tang. In vitro functional assays were performed to evaluate the pathogenic properties of CD8+CD28null Tang. Results: CD8+CD28null Tang levels were significantly higher in the peripheral blood of AAV patients compared to HCs, and their levels were further increased in AAV patients with MPO⁺, p-ANCA⁺, or interstitial lung disease compared to their respective control groups. Additionally, there was a positive correlation between both the percentage and absolute count of CD8+CD28null Tang and the Birmingham Vasculitis Activity Score (BVAS). In patients with a good treatment response, both the percentage and absolute count of CD8+CD28null Tang were significantly reduced, and this reduction was positively correlated with the decrease in BVAS scores. In vitro studies revealed that CD8+CD28null Tang displayed enhanced chemotactic properties, induced apoptosis in human umbilical vein endothelial cells (HUVECs), and inhibited their proliferation, migration, and tube formation. Conclusions: AAV patients exhibit increased levels of circulating CD8+CD28null Tang, which can be reduced following effective treatment. Furthermore, CD8+CD28null Tang may contribute to the pathogenesis of AAV by promoting apoptosis and inhibiting the proliferation, migration, and tube formation of HUVECs.

Association of tyrosine kinase 2 polymorphisms with susceptibility to microscopic polyangiitis in a Guangxi population

Background

Heredity and epigenetics affect the pathogenesis of microscopic polyangiitis (MPA). Tyrosine kinase 2 (TYK2) polymorphisms (rs2304256C > A, rs280519A > G, and rs12720270G > A) may be potential protective factors against anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Current research suggests that TYK2 is associated with various autoimmune diseases; however, no study has examined the relationship between TYK2 polymorphisms and AAV. This study assessed the effect of TYK2 polymorphisms on susceptibility to MPA.

Methods

Overall, 562 Chinese participants (265 patients with MPA and 297 healthy volunteers) were recruited. Polymerase chain reactions combined with high-throughput sequencing were used to analyze polymorphic loci, while logistic regression analysis was used to assess the relationship between polymorphism of the TYK2 gene and MPA susceptibility.

Results

In males, individuals with the CA genotype (rs2304256) in the overdominant model showed a significantly reduced risk of MPA (odds ratio (OR) = 0.52; 95% confidence interval (CI) [0.29-0.93]; p = 0.025). Regarding rs280519, male carriers of the AG genotype had a significantly lower risk of developing MPA in both the codominant (OR = 0.51; 95% CI [0.28-0.93]; p = 0.039) and overdominant (OR = 0.48; 95% CI [0.27-0.86]; p = 0.013) models. The GA genotype of rs12720270 was associated with low susceptibility to MPA in males (OR = 0.52; 95% CI [0.29-0.93]; p = 0.027).

Conclusions

This study indicates that mutations in the TYK2 gene (rs2304256, rs280519, and rs12720270) may be associated with a reduced risk of MPA in the male Chinese population in Guangxi. The A allele of single nucleotide polymorphism (SNP) rs2304256 may be a protective factor against MPA, while the G alleles of SNPs rs280519 and rs12720270 are protective factors against MPA.

Childhood-Onset ANCA-Associated Vasculitis: From Genetic Studies to Advances in Pathogenesis, Classification and Novel Therapeutic Approaches

Childhood-onset antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) represents a heterogeneous group of multi-system autoimmune conditions associated with chronic inflammation, characteristically affecting small blood vessels, leading to various organ and system manifestations. Although rare in paediatric populations, AAV poses challenges in early recognition, diagnosis and management of refractory cases. This review highlights the characteristics of clinical presentation and outcomes of AAV in children, as well as its current classification and progress achieved in understanding the disease pathogenesis, with a focus on adult and paediatric genetic studies. Furthermore, we discuss the management of AAV in children, as well as new emerging therapies and future research needs, while proposing a potential algorithm for a childhood-onset-AAV therapeutic approach based on the disease phenotype.

Integrated bioinformatic analysis of the shared molecular mechanisms between ANCA-associated vasculitis and atherosclerosis

BACKGROUND AND OBJECTIVE

Accumulated evidence supports the tendency of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis(AAV) to coexist with atherosclerosis (AS). However, the common etiology of these two diseases remains unclear. This study aims to explore the mechanisms underlying the concurrent occurrence of ANCA and AS.

METHODS

Microarray data of AAV and AS were examined in a comprehensive gene expression database. Weighted gene co-expression network analysis (WGCNA) and differential gene expression analysis (GEO2R) were performed to identify common genes between AAV and AS. Based on the co-expressed genes, functional enrichment analysis, protein-protein interaction (PPI) network analysis, and identification of hub genes (HGs) were conducted. Subsequently, co-expression analysis of HGs was performed, and their expression and diagnostic value were validated. We further explored immune cell infiltration and analyzed the correlation between HGs and infiltrating immune cells. Finally, the reliability of the selected pathways was verified.

RESULTS

The results of the common gene analysis suggest that immune and inflammatory responses may be common features in the pathophysiology of AAV and AS. Through the interaction of different analysis results, we confirmed five HGs (CYBB, FCER1G, TYROBP, IL10RA, CSF1R). The CytoHubba plugin and HG validation demonstrated the reliability of the selected five HGs. Co-expression network analysis revealed that these five HGs could influence monocyte migration. Analysis of immune cell infiltration showed that monocytes in ANCA and M0 macrophages in AS constituted a higher proportion of all infiltrating immune cells, with significant differences in infiltration. We also found significant positive correlations between CYBB, FCER1G, TYROBP, IL10RA, CSF1R, and monocytes/M0 macrophages in AAV, as well as between CYBB, FCER1G, TYROBP, IL10RA, CSF1R, and M0 macrophages in AS.

CONCLUSION

These five HGs can promote monocyte differentiation into macrophages, leading to the concurrent occurrence of AAV and AS. Our study provides insights into the mechanisms underlying the coexistence of AAV and AS.

Systems Immunology Approaches to Understanding Immune Responses in Acute Infection of Yellow Fever Patients

In the 2018 yellow fever (YF) outbreak in Brazil, we generated new transcriptomic data and combined it with clinical and immunological data to decode the pathogenesis of YF. Analyzing 79 patients, we found distinct gene expression patterns between acute YF, other viral infections, and the milder YF-17D vaccine infection. We identified a critical role for low-density, immature neutrophils in severe outcomes, marked by the downregulation of genes essential for neutrophil migration and maturation, such as PADI4, CSF3R, and ICAM1, in deceased patients. Our study also revealed complex interactions among inflammation-related genes, including increased CXCL10 and IL1R2 expression and decreased IL-1b expression in the acute phase. The diminished expression of HLA class II genes indicates impaired antigen presentation. These findings highlight the delicate balance of immune responses in YF pathogenesis and lay the groundwork for future therapeutic and diagnostic advancements.

Genetics of vasculitis

Systemic vasculitis encompasses a wide range of conditions characterized by varying degrees of inflammation in blood vessels. Although the etiology of vasculitis remains unclear, accumulated data suggest that it is triggered in genetically predisposed individuals by the concurrence of certain environmental factors. The importance of the genetic component has been consistently supported by evidence of familial aggregation, differential prevalence by ethnicity, and multiple genetic associations with disease susceptibility and severity reported in recent years. The strongest association signals in most vasculitides correspond to genetic variants within the HLA region, suggesting an important role of the immune system in its pathophysiology. However, each type of vasculitis has distinct defining HLA association markers, likely due to disease-specific differences in antigenic drivers. Furthermore, other genetic polymorphisms located outside the HLA region play an important role in susceptibility to different vasculitides. More recent research has assessed the shared genetic susceptibility evident across different vasculitides. Future studies should focus on the identification of genetic markers that can serve as reliable biomarkers for early diagnosis, prognosis, and treatment response in systemic vasculitis.

Polymorphisms of the SERPINA1 gene are associated with higher mortality in a Brazilian cohort of ANCA-associated vasculitis patients

BACKGROUND

Alpha-1-Antitrypsin (A1AT) is a protease inhibitor encoded by the SERPINA1 gene. A1AT serves as the primary natural inhibitor of Proteinase 3 (PR3), an enzyme found in neutrophils. PR3 is an antigenic target of Anti-Neutrophil Cytoplasmic Antibodies (ANCA). While numerous studies have established a connection between Single Nucleotide Polymorphisms (SNPs) in the SERPINA1 gene and ANCA-Associated Vasculitis (AAV), limited research has delved into the impact of these polymorphisms on the prognosis of these patients.

OBJECTIVE

The present study's objective is to investigate mortality disparities among Brazilian AAV patients carrying SERPINA1 SNPs (rs7151526, rs28929454) compared to non-carriers. Additionally, the authors analyzed demographic, clinical, and serologic data in these two groups.

METHODS

In this single-center prospective cohort study, the authors enrolled AAV patients who were monitored for a duration of up to three years. The identification of SNPs was conducted through RT-PCR. Survival analysis, including Kaplan-Meier survival curves, and Cox proportional regression analysis was subsequently performed to evaluate outcomes.

RESULTS

The authors assessed 115 patients (65.2% with granulomatosis with polyangiitis, 17.4% with eosinophilic granulomatosis with polyangiitis, and 17.4% with microscopic polyangiitis). All patients were aged ≥ 18 years, with 37.4% being female, and 54.7% identified as White. The association between SERPINA1 SNPs proved to be the most significant factor linked to mortality in the cohort (HR = 6.2, 95% CI 1.4‒27.1, p = 0.015). SERPINA1 SNP carriers exhibited a lower mean survival [rs7151526: 57.4 (42.7‒72.2) years, p < 0.007; rs28929454: 54.9 (40.9‒68.9) years, p < 0.0001] than non-carriers (68.0 [67.2‒69.0] years).

CONCLUSION

SERPINA1 SNPs are associated with increased mortality in Brazilian AAV patients.

Serum protein profiling reveals distinct patient clusters in giant cell arteritis

OBJECTIVES

We investigated the potential of serum proteins for distinguishing clinical and molecular subtypes in patients with GCA.

METHODS

Proximity extension assays were used to analyse 1463 proteins in serum samples from patients with new-onset GCA (n = 16) and patients who have achieved remission (n = 13). Unsupervised and supervised cluster analyses were performed.

RESULTS

Unsupervised cluster analysis identified three distinct clusters based on the protein signature. Compared with cluster 2, patients of cluster 1 had fewer PMR symptoms, increased levels of macrophage migration inhibitory factor (MIF) and pronounced NF-κB, STAT5 and IL-1 signalling. The changes in serum proteins upon remission differed between cluster 1 and 2.Patients with cranial GCA were characterized by altered endothelial and Th17 signalling, whereas patients not responding to treatment within the GUSTO-trial showed increased Th1 and diminished B cell signalling. Patients with anterior ischaemic optic neuropathy displayed higher levels of CHI3L1 (YKL40) and MMP12, and reduced levels of TIMP3.

CONCLUSION

Protein profiling identified patient clusters in GCA with distinct proteomic features and therefore likely different pathophysiology. These unique proteomic footprints might lead to more targeted treatments in future.

Approach to the patient with eosinophilia in the era of tyrosine kinase inhibitors and biologicals

PURPOSE OF REVIEW

In this review, we aim to explore the optimal approach to patients presenting with eosinophilia, considering recent advances in diagnostic and therapeutic strategies. Specifically, we focus on the integration of novel therapies into clinical practice to improve patient outcomes.

RECENT FINDINGS

Advanced insights into the clinical and genetic features of eosinophilic disorders have prompted revisions in diagnostic criteria by the World Health Organization classification (WHO-HAEM5) and the International Consensus Classification (ICC). These changes reflect a growing understanding of disease pathogenesis and the development of targeted treatment options. The therapeutic landscape now encompasses a range of established and novel therapies. For reactive conditions, drugs targeting the eosinophilopoiesis, such as those aimed at interleukin-5 or its receptor, have demonstrated significant potential in decreasing blood eosinophil levels and minimizing disease flare-ups and relapse. These therapies have the potential to mitigate the side effects commonly associated with prolonged use of oral corticosteroids or immunosuppressants. Myeloid and lymphoid neoplasms with eosinophilia and tyrosine kinase (TK) gene fusions are managed by various TK inhibitors with variable efficacy. Diagnosis and treatment rely on a multidisciplinary approach. By incorporating novel treatment options into clinical practice, physicians across different disciplines involved in the management of eosinophilic disorders can offer more personalized and effective care to patients. However, challenges remain in accurately diagnosing and risk-stratifying patients, as well as in navigating the complexities of treatment selection.

Neutrophil extracellular traps in homeostasis and disease

Neutrophil extracellular traps (NETs), crucial in immune defense mechanisms, are renowned for their propensity to expel decondensed chromatin embedded with inflammatory proteins. Our comprehension of NETs in pathogen clearance, immune regulation and disease pathogenesis, has grown significantly in recent years. NETs are not only pivotal in the context of infections but also exhibit significant involvement in sterile inflammation. Evidence suggests that excessive accumulation of NETs can result in vessel occlusion, tissue damage, and prolonged inflammatory responses, thereby contributing to the progression and exacerbation of various pathological states. Nevertheless, NETs exhibit dual functionalities in certain pathological contexts. While NETs may act as autoantigens, aggregated NET complexes can function as inflammatory mediators by degrading proinflammatory cytokines and chemokines. The delineation of molecules and signaling pathways governing NET formation aids in refining our appreciation of NETs' role in immune homeostasis, inflammation, autoimmune diseases, metabolic dysregulation, and cancer. In this comprehensive review, we delve into the multifaceted roles of NETs in both homeostasis and disease, whilst discussing their potential as therapeutic targets. Our aim is to enhance the understanding of the intricate functions of NETs across the spectrum from physiology to pathology.

Update on antineutrophil cytoplasmic autoantibody vasculitis in children

PURPOSE OF REVIEW

Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) is often organ- or life-threatening in children and impacts them during important periods of psychosocial and physical development. This review covers recent advances in the pathophysiology, diagnosis, management, and outcomes of AAV in children and highlights the ongoing need for funding and increased research collaboration.

RECENT FINDINGS

Recent work has improved our understanding of AAV disease pathogenesis, potentially identifying new biomarkers and therapeutic targets. Collaborative clinical studies have also highlighted the variable manifestations in children and identified potential factors associated with poorer outcomes. Consensus-based treatment guidelines are also appearing, but clinical trials are still essential to better understanding treatment efficacy and safety in children affected by AAV. New, validated outcome measures, including those that are patient-reported, will facilitate these much-needed clinical trials in pediatric AAV.

SUMMARY

There is a continued need for more rigorous study in pediatric AAV, however, there is certainly excitement with the increase in recent research relevant to the pediatric population.

Genetic and Non-Genetic Contributions to Eosinophilic Granulomatosis with Polyangiitis: Current Knowledge and Future Perspectives

In this work, we present a comprehensive overview of the genetic and non-genetic complexity of eosinophilic granulomatosis with polyangiitis (EGPA). EGPA is a rare complex systemic disease that occurs in people presenting with severe asthma and high eosinophilia. After briefly introducing EGPA and its relationship with the anti-neutrophil cytoplasmic autoantibodies (ANCA)-associated vasculitis (AAVs), we delve into the complexity of this disease. At first, the two main biological actors, ANCA and eosinophils, are presented. Biological and clinical phenotypes related to ANCA positivity or negativity are explained, as well as the role of eosinophils and their pathological subtypes, pointing out their intricate relations with EGPA. Then, the genetics of EGPA are described, providing an overview of the research effort to unravel them. Candidate gene studies have investigated biologically relevant candidate genes; the more recent genome-wide association studies and meta-analyses, able to analyze the whole genome, have confirmed previous associations and discovered novel risk loci; in the end, family-based studies have dissected the contribution of rare variants and the heritability of EGPA. Then, we briefly present the environmental contribution to EGPA, reporting seasonal events and pollutants as triggering factors. In the end, the latest omic research is discussed and the most recent epigenomic, transcriptomic and microbiome studies are presented, highlighting the current challenges, open questions and suggesting approaches to unraveling this complex disease.

Risk Assessment and Optimization for Pregnancy in Patients with Rheumatic Diseases

Patients with rheumatic diseases frequently operate with incomplete or incorrect information while planning for and experiencing pregnancy, often due to variability in provider care and knowledge. Risk assessment at each stage of pregnancy-pre-conception, during pregnancy, and postpartum-is focused on reducing maternal and neonatal complications. This review aims to compile updated, evidence-based guidance on how to minimize risk factors contributing to adverse pregnancy outcomes (APOs). Mitigation of known causes of infertility, appropriate testing and monitoring, achieving low disease activity on pregnancy-safe disease-modifying antirheumatic drugs (DMARDs) prior to conception, controlling hypertension (a frequent comorbidity among patients with certain rheumatic diseases), and the use of appropriate adjunctive medications (such as low-dose aspirin when preeclampsia risk is high) can optimize fertility and prevent adverse maternal and neonatal outcomes.

Protective effect of astaxanthin on ANCA-associated vasculitis

OBJECTIVE

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic autoimmune disease characterized by inflammation and fibrinoid necrosis of medium and small vessels, and its pathogenesis is closely related to inflammation and oxidative stress. Astaxanthin (ATX) is a carotenoid with anti-inflammatory, antioxidant, and immunomodulatory effects. We hypothesized that ATX could play a role in AAV treatment. This study aimed to investigate whether ATX has a protective effect against AAV and to elucidate its regulatory mechanism.

METHODS

In vitro experiments, neutrophils isolated from healthy people were treated with ATX or not and cultured with serum from myeloperoxidase (MPO) -ANCA-positive patients and healthy persons. The levels of IL-6 and TNF-α in neutrophil culture supernatant before and after stimulation were measured. Neutrophil extracellular traps (NETs) and intracellular reactive oxygen species (ROS) in neutrophils were detected after stimulation. In vivo study, experimental autoimmune vasculitis (EAV) rat models were established and then treated with ATX via intragastric administration for 6 consecutive weeks. Urinary erythrocytes, urinary proteins, and serum creatinine were detected and HE staining was performed to assess renal injury in rats. Lung hemorrhage was observed by gross dissection and microscopic Prussian blue staining. The level of serum MPO-ANCA was detected. Serum IL-6, TNF-α, superoxide dismutase (SOD), and glutathione peroxidase (GSH-px) in rats were measured to explore the effects of ATX on oxidative stress and inflammation in EAV rats. The deposition of MPO in kidney and lung of rats was detected by immunohistochemistry.

RESULTS

ATX significantly inhibited neutrophil secretion of inflammatory factors IL-6 and TNF-α. ATX reduced the elevated levels of ROS in neutrophils stimulated by serum from AAV patients and alleviated the release of NETs. ATX administration was observed to reduce the degree of hematuria, proteinuria, and glomerular crescent formation in EAV rats. The degree of pulmonary hemorrhage was significantly reduced. Besides, the serum levels of IL-6 and TNF-α were attenuated, and antioxidant SOD and GSH-px increased in serum. Pathological results showed that MPO deposition was decreased in lung and kidney tissues after ATX treatment.

CONCLUSION

ATX could ameliorate the organ damages in EAV rats. It could serve as a hopeful therapy for AAV by its anti-inflammatory and anti-oxidative feature as a unique nature carotenoid.

ANCA in patients with systemic lupus erythematosus. A cross sectional study in Brazilian patients and review of literature

BACKGROUND

Antineutrophil cytoplasmatic antibodies (ANCA) have been detected in patients with systemic lupus erythematosus (SLE). In this study, we investigated the presence of ANCA in a sample of Brazilian SLE patients and its possible associations with clinical and serological outcomes. Additionally, we reviewed the literature of on ANCA in SLE.

RESULTS

The presence of ANCA was detected in 130 patients using indirect immunofluorescence (IIF). The test was positive in 29.9% of the cases (17.6% pANCA and 11.5% cANCA). Male sex and peripheral vasculitis were more prevalent in the ANCA-positive sample. cANCA was associated with lupus anticoagulant and pANCA had a positive association with peripheral vasculitis and a negative association with anti- SSB/La antibodies. In the 22 studies included in the literature review, a wide range of ANCA positivity was found (13% to 81.1% by IIF and 0 to 22.2% by ELISA). ANCA was associated with renal damage in the Asian population. Although other associations have been found in isolated studies, they were not consistently reported.

CONCLUSIONS

The ANCA prevalence found in this Brazilian sample was within the range reported in the literature and these autoantibodies were more frequent in males and in patients with vasculitis. The literature showed controversial results on the association between ANCA and SLE disease activity or clinical characteristics.

Acute interstitial nephritis caused by ANCA-associated vasculitis: a case based review

Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) typically manifests as rapidly progressive glomerulonephritis with crescent formation. In this report, we present a local case of myeloperoxidase (MPO)-AAV-associated acute interstitial nephritis (AIN), showing slight pauci-immune glomerulonephritis and positive MPO-ANCA. This case is characterized by foot process effacement of podocytes in the glomerulus, a favorable prognosis, and an absence of crescentic formation. To further understand this condition, we conducted a comprehensive literature search on Google Scholar and PubMed, employing both free text words and MeSH terms related to "AAV and AIN." This search yielded 24 cases, which we analyzed for their clinical features, laboratory findings, renal pathological characteristics, and therapeutic outcomes. AAV-associated interstitial nephritis predominantly affects elderly patients and is often associated with anemia, proteinuria, hematuria, and nonspecific manifestations, including fever, anorexia, fatigue, edema, and weight loss. Most of the cases in our review were MPO-ANCA-positive and exhibited isolated interstitial inflammation. These patients typically presented with relatively lower levels of serum creatinine, 24-h urine protein levels, and MPO-ANCA titers. All patients in our study received immunosuppressive therapy, including glucocorticoids, immunosuppressants, and rituximab, with the majority achieving clinical remission. Isolated AIN in the context of AAV is a rare occurrence, but it displays distinct clinical, laboratory, and pathological features. Patients with this presentation show a positive response to immunosuppressive treatment. Nevertheless, the establishment of definitive therapy guidelines for AAV-associated AIN remains uncertain and necessitates further investigation to develop comprehensive treatment guidelines. AIN, particularly when lacking typical glomerulus lesions, may represent a novel subgroup within MPO-AAV warranting additional research and clinical attention. Key Points • This study contributes valuable scientific insights by highlighting that MPO-AAV-associated interstitial nephritis, even without crescentic formation, can exhibit podocyte foot process effacement and respond well to treatment. • The presence of AIN, independent of crescentic glomerulonephritis, suggests the potential emergence of a new subclass within MPA-AAV. • Notably, some cases of MPO-AAV-associated AIN may present with normal levels of Scr (Table 5, cases 5, 6, and 17). • This observation highlights the importance of considering renal biopsy, diagnosis, and therapy in a timely manner to prevent the development of chronic kidney disease (CKD).

ANCA detection with solid phase chemiluminescence assay: diagnostic and severity association in vasculitis

ANCA-associated vasculitis (AAV) comprises a group of necrotizing vasculitis that mainly affects small- and medium-sized vessels. Serum anti-neutrophil cytoplasmic antibodies (ANCA), mainly anti-myeloperoxidase (anti-MPO) and anti-proteinase 3 (anti-PR3), levels may correlate to severity, prognosis, and recurrence of the disease. A retrospective analysis of 101 patients with MPO-positive and 54 PR3-positive vasculitis was performed, using laboratory established cut-off value, measured by chemiluminescence. Furthermore, data of renal disease and pulmonary involvement were collected at vasculitis diagnosis, as well as the progress, requiring dialysis, transplant, or mortality. For anti-MPO antibodies with a diagnosis of vasculitis (n = 77), an area under the curve (AUC) was calculated (AUC = 0.8084), and a cut-off point of 41.5 IU/ml was determined. There were significant differences in anti-MPO levels between patients with renal or pulmonary dysfunction (n = 65) versus those without them (n = 36) (p = 0.0003), and a cut-off threshold of 60 IU/ml was established. For anti-PR3 antibodies with a diagnosis of vasculitis (n = 44), an area under the curve (AUC) was calculated (AUC = 0.7318), and a cut-off point of 20.5 IU/ml was determined. Significant differences in anti-PR3 levels were observed between those patients with renal or pulmonary dysfunction (n = 30) and those without them (n = 24) (p = 0.0048), and a cut-off threshold of 41.5 IU/ml was established. No significant differences between those patients who had a worse disease progression and those who did not were found for anti-MPO and anti-PR3. Anti-MPO and anti-PR3 levels at the moment of vasculitis diagnosis are related with disease severity but not with disease outcome or vasculitis recurrence.

Analysis of Thyroid Function in ANCA-Associated Vasculitis Patients with Renal Injury

BACKGROUND

Previous studies indicated common thyroid dysfunction in various kidney diseases. This study aimed to investigate the thyroid function in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV) with renal injury.

METHODS

Briefly, 174 patients diagnosed as having AAV with renal injury and without previous thyroid disease history were included in the retrospective and prospective study. The clinical parameters were collected and compared between different groups.

RESULTS

Of the patients included, 24 exhibited normal thyroid function, while 150 had thyroid dysfunction, including 55 (36.67%) with hypothyroidism. Those AAV patients with thyroid dysfunction showed different clinical parameters from those with normal thyroid function. The patients were followed up for a median of 68.6 (64.3; 72.8) months. Those with thyroid dysfunction were more prone to progressing to dialysis dependence compared to the group with normal thyroid function. Logistic regression analysis showed advanced age and decreased albumin as independent risk factors for thyroid dysfunction in patients with AAV. Survival analysis and multivariate Cox regression analysis showed that thyroid dysfunction was a risk factor for AAV patients with renal injury to progress to the endpoint of dialysis dependence.

CONCLUSION

Thyroid dysfunction, predominantly hypothyroidism, was commonly complicated in AAV patients with renal injury. AAV patients with thyroid dysfunction were presented with different clinical parameters and more prone to progressing to dialysis dependence compared to those with normal thyroid function.

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

BACKGROUND

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.

AIMS

This study aimed to investigate new treatment options for AAV through a combination of bioinformatics analysis and cell molecular experiments.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Characterization of Novel Alpha-1-Antitrypsin Coding Variants in a Mammalian Cellular Model

Advances in genetic screening technologies have considerably accelerated the discovery of rare alpha-1-antitrypsin (AAT) variants. Expression in cellular models is an effective approach to evaluate the pathogenic potential of these new AAT variants, whose clinical significance would otherwise remain uncertain. Here we provide a detailed description of established methods for in vitro characterization of AAT coding variants expressed in HEK293T/17 cells. The protocols include determination of secretion efficiency, the tendency to form polymeric chains and  the anti-elastase inhibitory activity.

Benralizumab for eosinophilic granulomatosis with polyangiitis: a retrospective, multicentre, cohort study

BACKGROUND

Interleukin-5 (IL-5) inhibitors represent novel therapies for eosinophilic granulomatosis with polyangiitis (EGPA). This study assessed the effectiveness and safety of the IL-5 receptor inhibitor benralizumab in a European cohort of patients with EGPA.

METHODS

This retrospective cohort study included patients with EGPA from 28 European referral centres of the European EGPA Study Group across six countries (Italy, France, UK, Russia, Spain, and Switzerland) who received benralizumab as any line of treatment between Jan 1, 2019, and Sep 30, 2022. We assessed the rates of complete response, defined as no disease activity (Birmingham Vasculitis Activity Score [BVAS] of 0) and a prednisone dose of up to 4 mg/day, in contrast to partial response, defined as a BVAS of 0 and a prednisone dose greater than 4 mg/day. Active disease manifestations, pulmonary function, variation in glucocorticoid dose, and safety outcomes were also assessed over a 12-month follow-up.

FINDINGS

121 patients with relapsing-refractory EGPA treated with benralizumab at the dose approved for eosinophilic asthma were included (64 [53%] women and 57 [47%] men; median age at the time of beginning benralizumab treatment 54·1 years [IQR 44·2-62·2]). Complete response was reported in 15 (12·4%, 95% CI 7·1-19·6) of 121 patients at month 3, 25 (28·7%, 19·5-39·4) of 87 patients at month 6, and 32 (46·4%, 34·3-58·8) of 69 patients at month 12; partial response was observed in an additional 43 (35·5%, 27·0-44·8) patients at month 3, 23 (26·4%, 17·6-37·0) at month 6, and 13 (18·8%, 10·4-30·1) at month 12. BVAS dropped from 3·0 (IQR 2·0-8·0) at baseline to 0·0 (0·0-2·0) at months 3 and 6, and to 0·0 (0·0-1·0) at month 12. The proportion of patients with systemic manifestations, active peripheral neurological disease, ear, nose, and throat involvement, and pulmonary involvement decreased, with an improvement in lung function tests. Six patients relapsed after having a complete response. The oral prednisone (or equivalent) dose decreased from 10·0 mg/day (5·0-12·5) at baseline to 5·0 mg/day (3·6-8·5) at month 3 (p<0·01), to 5·0 mg/day (2·5-6·3) at month 6, and to 2·5 mg/day (0·0-5·0) at month 12 (p<0·0001). 19 (16%) of 121 patients had adverse events and 16 (13%) discontinued benralizumab.

INTERPRETATION

These data suggest that benralizumab could be an effective treatment for EGPA in real-life clinical practice. Further clinical trials are required to confirm the efficacy of benralizumab in patients with a higher baseline disease activity.

FUNDING

None.

Profile, Healthcare Resource Consumption and Related Costs in ANCA-Associated Vasculitis Patients: A Real-World Analysis in Italy

INTRODUCTION

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are rare autoimmune diseases triggering inflammation of small vessels. This real-world analysis was focused on the most common AAV forms, granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), to describe patients' demographic and clinical characteristics, therapeutic management, disease progression, and the related economic burden.

METHODS

A retrospective analysis was conducted on administrative databases of a representative sample of Italian healthcare entities, covering approximately 12 million residents. Between January 2010 and December 2020, adult GPA patients were identified by payment waiver code or hospitalization discharge diagnosis, and MPA patients by payment waiver code with or without hospitalization discharge diagnosis. Clinical outcomes were evaluated through AAV-related hospitalizations, renal failure onset, and mortality. Economic analysis included healthcare resource utilization deriving from drugs, hospitalizations, and outpatient specialist services. The related mean direct costs year/patient were also calculated in patients stratified by presence/absence of glucocorticoid therapy and type of inclusion criterion (hospitalization/payment waiver code).

RESULTS

Overall, 859 AAV patients were divided into GPA (n = 713; 83%) and MPA (n = 146; 17%) cohorts. Outcome indicators highlighted a clinically worse phenotype associated with GPA compared to MPA. Cost analysis during follow-up showed tendentially increased expenditures in glucocorticoid-treated patients versus untreated (overall AAV: €8728 vs. €7911; GPA: €9292 vs. €9143; MPA: €5967 vs. €2390), mainly driven by drugs (AAV: €2404 vs. €874; GPA: €2510 vs. €878; MPA: €1881 vs. €854) and hospitalizations.

CONCLUSION

Among AAV forms, GPA resulted in a worse clinical picture, higher mortality, and increased costs. This is the first real-world pharmaco-economic analysis on AAV patients stratified by glucocorticoid use on disease management expenditures. In both GPA and MPA patients, glucocorticoid treatment resulted in higher healthcare costs, mostly attributable to medications, and then hospitalizations, confirming the clinical complexity and economic burden for management of patients with autoimmune diseases under chronic immunosuppression.

Eosinophilic granulomatosis with polyangiitis following flu guard influenza vaccination: A case report

Key Clinical Message

This case highlights a potential association between influenza vaccination and the development of eosinophilic granulomatosis with polyangiitis (EGPA), prompting the need for increased vigilance regarding vaccine-related autoimmune reactions. While causality remains unclear, clinicians should consider this possibility in patients presenting with EGPA-like symptoms shortly after vaccination.

Abstract

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis characterized by tissue infiltration by eosinophils and hyper eosinophilia. We present a case of EGPA in a middle-aged man following influenza vaccination. The patient developed respiratory symptoms, skin lesions, joint pain, and neurological deficits. Diagnostic tests revealed eosinophilia, positive anti-neutrophil cytoplasmic antibodies, and elevated acute phase reactants. This report highlights a potential association between influenza vaccination and EGPA.

Practical recommendations for managing severe chronic rhinosinusitis with nasal polyps in the era of biologics

Objective

We conducted a national survey to understand how rhinology practice has changed with the advent of biologics and how this affected patients with uncontrolled, severe chronic rhinosinusitis with nasal polyps (CRSwNP). We aimed to analyse the results of the survey and infer practical recommendations for clinical practice.

Methods

A group of ear, nose, and throat specialists (ENTs) experienced in the management of CRSwNP developed a 74-question survey. ENTs from rhinology centres authorised to prescribe biologics in the context of the national health system were invited to answer it between 01/05/2022 and 31/07/2022. The responses underwent descriptive analyses, and the authors discussed the results and derived practical recommendations for clinical practice.

Results

ENTs working in rhinology centres changed their practices coinciding with the advent of biologics. CRSwNP evaluations have become more complex because they involve diagnostic confirmation, determining the patients' immunologic profile, and other factors. We observed heterogenous behaviours in practice that may be conditioned by the novelty of the topic. The results of the survey were used to develop practical recommendations for ENTs and are summarised herein.

Conclusions

Clinical practice in rhinology outpatient clinics has changed profoundly in the era of biologics. Our practical recommendations for clinicians working in rhinology centres are expected to help standardise practice and improve care.

Eosinophilic Granulomatosis with Polyangiitis: Latest Findings and Updated Treatment Recommendations

Eosinophilic granulomatosis with polyangiitis (EGPA) causes necrotizing vasculitis and eosinophil-rich granulomatous inflammation in small- to medium-sized vessels, resulting in multiple organ damage. EGPA is classified as an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, with myeloperoxidase-ANCA detected in approximately one-third of the patients. Conventional treatment of EGPA relies on systemic glucocorticoids (GCs) in combination with cyclophosphamide when poor prognostic factors are present; however, the dilemma between disease control and drug-related adverse effects has long been a challenge. Recent studies have revealed that the genetic background, pathophysiology, and clinical manifestations differ between ANCA-positive and ANCA-negative patients; however, mepolizumab, an interleukin (IL)-5 inhibitor, is effective in both groups, suggesting that the IL-5-eosinophil axis is deeply involved in the pathogenesis of both ANCA-positive and ANCA-negative EGPA. This review summarizes the latest knowledge on the pathophysiology of EGPA and focuses on the roles of eosinophils and ANCA. We then introduce the current treatment recommendations and accumulated evidence for mepolizumab on EGPA. Based on current unmet clinical needs, we discuss potential future therapeutic strategies for EGPA.

Seasonal Influence on Development of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: A Retrospective Cohort Study Conducted at Multiple Institutions in Japan (J-CANVAS)

OBJECTIVE

To clarify seasonal and other environmental effects on the onset of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

METHODS

We enrolled patients with new-onset eosinophilic granulomatosis with polyangiitis (EGPA), microscopic polyangiitis (MPA), and granulomatosis with polyangiitis (GPA) registered in the database of a Japanese multicenter cohort study. We investigated the relationship between environmental factors and clinical characteristics. Seasons were divided into 4 (spring, summer, autumn, and winter), and the seasonal differences in AAV onset were analyzed using Pearson chi-square test, with an expected probability of 25% for each season.

RESULTS

A total of 454 patients were enrolled, with a mean age of 70.9 years and a female proportion of 55.5%. Overall, 74, 291, and 89 patients were classified as having EGPA, MPA, and GPA, respectively. Positivity for myeloperoxidase (MPO)-ANCA and proteinase 3 (PR3)-ANCA was observed in 355 and 46 patients, respectively. Overall, the seasonality of AAV onset significantly deviated from the expected 25% for each season (P = 0.001), and its onset was less frequently observed in autumn. In ANCA serotypes, seasonality was significant in patients with MPO-ANCA (P < 0.001), but not in those with PR3-ANCA (P = 0.97). Additionally, rural residency of patients with AAV was associated with PR3-ANCA positivity and biopsy-proven pulmonary vasculitis.

CONCLUSION

The onset of AAV was influenced by seasonal variations and was less frequently observed in autumn. In contrast, the occurrence of PR3-ANCA was triggered, not by season, but by rural residency.

Circulating Calprotectin (cCLP) in autoimmune diseases

BACKGROUND AND AIM

Calprotectin (CLP) is a heterodimeric complex formed by two S100 proteins (S100A8/A9), which plays a pivotal role in innate immunity. Due to its intrinsic cytotoxic and proinflammatory properties, CLP controls cell differentiation, proliferation and NETosis and has been associated with a wide range of rheumatic diseases. Our review summarizes the widespread interest in circulating CLP (cCLP) as a biomarker of neutrophil-related inflammation, in autoimmune rheumatic disease (ARD) and non-ARD.

METHODS

A thorough literature review was performed using PubMed and EMBASE databases searching for circulating calprotectin and synonyms S100A8/A9, myeloid-related protein 8/14 (MRP8/MRP14), calgranulin A/B and L1 protein in addition to specific ARDs and autoimmune non-rheumatic diseases. We selected only English-language articles and excluded abstracts without the main text.

RESULTS

High cCLP serum levels are associated with worse structural outcomes in rheumatoid arthritis and to a lesser extent, in spondyloarthritis. In addition, cCLP can predict disease relapse in some autoimmune diseases including systemic lupus erythematosus (SLE), anti-neutrophil cytoplasmic antibodies-associated vasculitis (AAV) and some severe manifestations of connective tissue diseases, such as glomerulonephritis in SLE, AAV, juvenile idiopathic arthritis, adult-onset Still's disease and lung fibrosis in systemic sclerosis. Therefore, cCLP levels enable the identification of patients who need an accurate and tight follow-up. The clinical usefulness of cCLP as an inflammatory marker has been suggested for inflammatory/autoimmune non-rheumatic diseases, and especially for the monitoring of the inflammatory bowel diseases patients. Currently, there are only a few studies that evaluated the cCLP efficacy as a clinical biomarker in inflammatory/autoimmune non-rheumatic diseases with controversial results. Future studies are warranted to better clarify the role of cCLP in relation to the disease severity in myasthenia gravis, multiple sclerosis, chronic inflammatory demyelinating polyneuropathy, Graves' orbitopathy, autoimmune bullous diseases and uveitis.

CONCLUSION

Our literature review supports a relevant role of cCLP as potential prognostic biomarker mirroring local or systemic inflammation, especially in chronic inflammatory rheumatic diseases.

Association between the AKT1 single nucleotide polymorphism (rs2498786, rs2494752 and rs5811155) and microscopic polyangiitis risk in a Chinese population

Microscopic polyangiitis (MPA) is an autoimmune disease, characterized by ANCA in blood and necrotizing inflammation of small and medium-sized vessels, one of the three clinical phenotypes of ANCA-associated vasculitis (AAV). Autophagy has been confirmed to be involved in the pathogenesis of AAV. AKT1 is one of the autophagy-regulated proteins. Its single nucleotide polymorphisms (SNPs) are associated with multiple immune-related diseases, but there are rarely studies in AAV. The incidence rate of AAV has a notable geographic difference, and MPA is predominant in China. The aim of this study was to investigate the association between AKT1 SNP and MPA risk. Genotypes of 8 loci in AKT1 were evaluated by multiplex polymerase chain reaction (PCR) and high-throughput sequencing in 416 people, including 208 MPA patients and 208 healthy volunteers from Guangxi in China. Additionally, data of 387 healthy volunteers from China were obtained from the 1000Genomes Project on public database. Differences were observed between the loci (rs2498786, rs2494752, and rs5811155) genotypes in AKT1 and MPA risk (P = 7.0 × 10^-4, P = 3.0 × 10^-4, and P = 5.9 × 10^-5, respectively). A negative association was detected in the Dominant model (P = 1.2 × 10^-3, P = 2.0 × 10^-4 and P = 3.6 × 10^-5, respectively). A haplotype (G-G-T) was associated with MPA risk negatively (P = 7.0 × 10^-4). This study suggests that alleles (rs2498786 G, rs2494752 G and rs5811155 insT) are protective factors for MPA and alleles (rs2494752 G and rs5811155 insT) for MPO-ANCA in patients with MPA. There is a haplotype (G-G-T), which is a protective factor for MPA. It suggests that the role of AKT1 in MPA/AAV needs further study to provide more intervention targets for MPA/AAV.

New insights into the metabolism of Th17 cells

T helper 17 (Th17) cells are IL-17-producing CD4 T cells that play a crucial role in autoimmune diseases. IL-17 is a key cytokine for host protection against mucosal and skin infection but is also one of the major pathogenic cytokines. IL-1 and IL-23 are requisite for stimulating pathogenic Th17 cell differentiation and proliferation. Therapeutics targeting the IL-17/IL-23 pathway are widely used clinically for the treatment of autoimmune diseases. Besides IL-17, pathogenic Th17 cells produce granulocyte-macrophage colony-stimulating factor, tumor necrosis factor α, interferon γ, IL-21 and IL-22. However, Th17-targeted therapy has not yet been established. T cell metabolism orchestrates T cell survival, cell differentiation, epigenetic change and function and each T cell subset favors a particular metabolic pathway. Recent studies have provided novel insights into the role of T cell metabolism in the pathogenesis of autoimmune diseases. The current review focuses on the role of Th17 cell metabolism in autoimmune diseases, particularly glycolysis, amino acid metabolism, lipid metabolism, as well as the regulators of these processes, including mTORC1. Therapeutics targeting T cell metabolism in autoimmune diseases could serve as a possible treatment option for patients who are refractory to or unresponsive to conventional therapy.

Polyangiitis overlap syndrome: a rare clinical entity

Polyangiitis overlap syndrome is a rare clinical entity comprising patients with overlapping features of more than one vasculitis, usually eosinophilic granulomatosis with polyangiitis (EGPA) and granulomatosis with polyangiitis (GPA). Few cases of polyangiitis overlap syndrome have been described in the literature, mostly associated with c-ANCA, anti-proteinase (PR)-3 positivity, a protean clinical picture characterized by vasculitis, eosinophilia and eosinophilic infiltrates in tissues and a favorable response to steroids and immunosuppressant treatments. Herein, we present a case of a 66-year-old woman with nasal obstruction, external nose deformity, sensorineural hearing loss, peripheral blood eosinophilia, high titer anti-PR3 antibodies and lung involvement. Nasal septum biopsies showed inflammatory infiltrate with eosinophilic component; histopathology of the lung demonstrated necrotizing granulomas associated with inflammatory infiltrate composed of numerous neutrophils and some eosinophils. The patient was diagnosed with polyangiitis overlap syndrome and successfully treated with cyclophosphamide. Recognizing this entity is fundamental given the distinct clinical phenotype and outcomes to therapy in the complex scenario of ANCA-associated vasculitides.

Biologics for eosinophilic granulomatosis with polyangiitis

PURPOSE OF REVIEW

The link between severe asthma and eosinophilic granulomatosis with polyangiitis (EGPA) in terms of pathophysiological background, clinical manifestations and disease evolution has leaded to investigate the relevance of anti T2 monoclonal antibodies licensed for severe asthma patients as a treatment option for EGPA. The present review aimed to provide un update on EGPA pathophysiology and to critically summarize the most robust evidence coming from trials and real-life setting on the use of anti T2 biologics in EGPA patients.

RECENT FINDINGS

Mepolizumab, an anti-interleukin-5 monoclonal antibody, is the only biologic drug targeting eosinophilic inflammation currently approved for EGPA treatment at the dose of 300 mg/4 weeks. Its use is restricted by the American College of Rheumatology guidelines to specific diseases phases and severity grades. However the most appropriate mepolizumab positioning and dose is still under investigation in the real life practice, which is providing an increasing amount of evidence confirming its efficacy, alone or in combination with other options in different disease stages. The relevance of other monoclonal antibodies interfering with T2 inflammation, including omalizumab and benralizumab, is under investigation but the evidence is still scarce.

SUMMARY

Taking into account the suboptimal medium-long term safety profile of conventional EGPA treatments, the opportunity of selectively targeting eosinophilic inflammation certainly represents a revolutionary approach. However, further real-word evidence is required to effectively position the new treatments in the light of the disease complexity, including different immunological drivers, and individual variability.

Microscopic polyangiitis presenting with persistent cough and hemoptysis in pediatrics: A case report and review of the literature

Background

Microscopic polyangiitis (MPA) is a necrotizing vasculitis that involves small- and medium-sized vessels and is associated with the presence of antineutrophil cytoplasmic antibodies with a perinuclear staining pattern (p-ANCA). The kidney and lungs are the organs primarily affected. MPA is rare in children and is easily misdiagnosed. Below is a complete case history of the course of the disease.

Case presentation

An 11-year-old girl with a 1-month history of cough and hemoptysis showed no improvement after imipenem-cilastatin treatment. p-ANCA and microscopic hematuria and proteinuria were positive, and a chest CT revealed an area of shadow in the bilateral lower lobe of the lungs. Renal biopsies showed crescentic glomerulonephritis, and MPA was diagnosed based on these criteria. The patient exhibited dramatic clinical and imaging improvements after immunosuppressive treatment.

Conclusion

The organs most commonly involved in MPA in children are the lungs, kidneys, skin, nervous system organs, and organs of the gastrointestinal tract. Careful examination should be carried out in these patients while biopsies of the kidney or any other organs remain the gold standard for diagnostic purposes. Pulmonary involvement may be the initial symptom of the disease and should not be confused with pneumonia. A urinalysis should be performed in patients with hemoptysis. Antibiotics should be used with caution.