Myeloperoxidase-antineutrophil Cytoplasmic Antibody Research Articles

Rapidly Progressive Glomerulonephritis (RPGN) Due to Myeloperoxidase Anti-neutrophil Cytoplasmic Antibodies (MPO-ANCA)-Associated Vasculitis and Anti-glomerular Basement Membrane (GBM) Disease

Rapidly Progressive Glomerulonephritis (RPGN) Due to Myeloperoxidase Anti-neutrophil Cytoplasmic Antibodies (MPO-ANCA)-Associated Vasculitis and Anti-glomerular Basement Membrane (GBM) Disease

Atypical Anti-GBM with ANCA Vasculitis- A Rarest of the Rare Entity: Index Case from Eastern India

Anti-glomerular basement membrane (GBM) antibody glomerulonephritis is an extremely rare glomerular disease. Around 90% of the patients are positive for serum anti-GBM antibodies while up to 10% can be negative. In such patients, only a kidney biopsy can reveal the anti-GBM disease it is then labeled as an atypical anti-GBM disease. Though anti-GBM disease can be associated with Anti Neutrophil Cytoplasmic Antibodies (ANCA) positivity, it is extremely rare to find atypical anti-GBM with ANCA positivity so much so that till now there are very few such cases reported from across the world. The case presented here is one such case where the patient presented with adult-onset nephrotic syndrome features with active urinary sediments and mildly deranged renal function. Myeloperoxidase (MPO) ANCA was positive and it was considered ANCA-associated crescentic glomerulonephritis (GN) but after the renal biopsy the picture was of anti-GBM disease. She was treated with pulse methylprednisolone but her creatinine increased in the meantime and considering anti-GBM she was put on Plasma Exchange (PLEX). She received 5 sessions of PLEX after which her renal function improved. She was also planned for Rituximab which could not be given due to local infection. As there are no protocols for treating such cases because of the extremely rare nature of the presentation, this case will increase the understanding of such presentations for the clinicians. This will help to plan for building the approach for such cases.

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.

#760 Monogenic lupus with ANCA associated vasculitis-phenotype and ANCA positivity due to DNASE1L3 mutations: case report and review of the literature

Abstract Background and Aims Monogenic systemic lupus erythematosus (SLE) accounts for 7-10% of cases of early-onset SLE. DNASE1L3 is an extracellular nuclease that digests chromatin released from apoptotic cells and its deficiency, enhance autoantibody production and type I interferon responses and cause different autosomal recessive phenotypes including SLE and hypocomplementemic urticarial vasculitis syndrome (HUVS) [1]. In some cases patients can have a mixed SLE-AAV phenotype. Kidney involvement in patients with DNASE1L3 mutations is poorly characterised. Method We present the case report of a 7-years-old boy with monogenic SLE due to DNASE1L3 mutations who developed severe glomerulonephritis leading to kidney failure. Results The patient had a history of urticaria and arthralgia and presented with fever, haemolytic anaemia, lymphadenopathy, hepato-splenomegaly, erythematous- macular and necrotic skin lesions, and interstitial lung disease. He also had acute kidney injury (serum creatinine 5.4 mg/dL), nephrotic- range proteinuria (3.9 g/24 h) and microhaematuria. Immunological tests revealed low C3 and C4, positive anti-nuclear antibody (ANA) and myeloperoxidase-antineutrophil cytoplasmic antibodies (MPO-ANCA), with negativity of anti-extractable nuclear antigen antibodies (anti-ENA) and anti-double stranded DNA (anti-dsDNA). Kidney biopsy showed pauci-immune (mesangial C3+ and IgG+) necrotising crescentic glomerulonephritis. The patient proved refractory to standard immunosuppression with cyclophosphamide and steroids. Two years later, due to renal function decline, a new kidney biopsy was performed and showed diffuse necrotising glomerulonephritis with endo- and extra-capillary proliferation; intense mesangial and subendothelial full-house deposits were evident on immunofluorescence. The patient did not respond to other lines of immunosuppression (mycophenolate mofetil, tacrolimus, azathioprine, rituximab), including the JAK inhibitor ruxolitinib. Kidney failure progressed to end stage at the age of 15 years, when the patient began haemodialysis. The kidney presentation, immunological profile and the first kidney biopsy led to diagnosis of AAV. However, the diagnosis was questioned due to the refractory course, the systemic clinical presentation and the second kidney histology (consistent with lupus nephritis). High interferon signature was detected and in the suspicion of a monogenic lupus nephritis Whole Exome Sequencing was performed and revealed homozygous DNASE1L3 variants (c.290_291delCA p.T97Ifs*2); thus, a final diagnosis of DNASE1L3 monogenic SLE was made. DNASE1L3 serum levels were normal but the DNAse enzymatic activity was low. Conclusion Renal involvement is one of the most frequent manifestations of DNASE1L3-related lupus; in the literature 32 cases of DNASE1L3-associated lupus nephritis are described. ANCA are positive in about 55% of these cases and are associated with a mixed lupus-AAV phenotype. All cases are characterized by resistance to common immunosuppressors and poor renal prognosis [2]. DNASE1L3 regulates neutrophil extracellular trap (NET) clearance and when this function is reduced the permanence of NETs induces endothelial damage and autoantibody formation. This pathogenic pathway is shared both by SLE and by AAV. There is no association between specific mutations and antibody positivity or clinical manifestations.

A case of eosinophilic granulomatosis with polyangiitis associated with diffuse alveolar haemorrhage: A case report and case-based review.

A 76-year-old man with bronchial asthma was admitted for respiratory failure and bloody sputum. A significant drop in haemoglobin and multiple consolidations supported clinical diagnosis of diffuse alveolar haemorrhage (AH). Myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) was positive and urinalysis suggested glomerulonephritis. Based on eosinophilia, sinusitis, peripheral nerve involvement, and leukocytoclastic vasculitis, he was diagnosed with eosinophilic granulomatosis with polyangiitis (EGPA) associated with AH. Our case-based review suggested that male predominance (65%), high positivity for ANCA (88%), and a high frequency of renal involvement (45%) may be characteristic of AH in EGPA. Although AH is rare in EGPA, we should be aware of this life-threatening complication.

Common Characteristics of Sinonasal Inflammation Associated with IgG4-Related Disease and Other Chronic Inflammatory Diseases: A Retrospective Observational Study

Plain Language SummaryImmunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory disease characterized by elevated serum IgG4 levels and tissue IgG4-positive cells. A part of IgG4-RD patients has sinonasal lesions. Because other inflammatory diseases also have features common to IgG4-RD, accurate knowledge of IgG4-RD is required. However, very little is known about IgG4-related rhinosinusitis. This study retrospectively analyzed clinicopathological features of IgG4-related rhinosinusitis and compared IgG4-related rhinosinusitis with other inflammatory diseases. Seven patients with sinonasal lesions and high serum IgG4 levels were retrospectively reviewed. Six of 7 patients were diagnosed with IgG4-RD, while one was diagnosed with granulomatosis with polyangiitis (GPA). In the 6 patients with IgG4-RD, intranasal findings showed nasal polyps in 3 patients (50%) and computed tomography showed ethmoid sinus involvement in 5 patients (83%), which shared common features with eosinophilic sinusitis (ECRS). However, no patients showed histopathological eosinophil infiltration. Although the patient with GPA revealed tissue infiltration of IgG4-positive cells in the nasal biopsy, the patient also had saddle nose and positivity of myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA), which indicated GPA. We diagnosed the patient with GPA, which is a known mimicker of IgG4-RD. In this study, the patients with IgG4-related rhinosinusitis had clinical and pathological characteristics similar to those of ECRS and GPA. IgG4-related rhinosinusitis should be diagnosed based on not only tissue infiltration of IgG4-positive cells but also systemic findings including nasal findings and serum ANCA levels. IgG4-RD should be ruled out in patients with eosinophilia without histopathological eosinophil infiltration.

Clinical features and prognosis of ANCA-associated vasculitis patients who were double-seropositive for myeloperoxidase-ANCA and proteinase 3-ANCA

Anti-neutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) patients with dual positivity for proteinase 3-ANCA (PR3-ANCA) and myeloperoxidase-ANCA (MPO-ANCA) are uncommon. We aimed to investigate these idiopathic double-positive AAV patients’ clinical features, histological characteristics, and prognosis. We reviewed all the electronic medical records of patients diagnosed with AAV to obtain clinical data and renal histological information from January 2010 to December 2020 in a large center in China. Patients were assigned to the MPO-AAV group or PR3-AAV group or idiopathic double-positive AAV group by ANCA specificity. We explored features of idiopathic double-positive AAV. Of the 340 patients who fulfilled the study inclusion criteria, 159 (46.76%) were female, with a mean age of 58.41 years at the time of AAV diagnosis. Similar to MPO-AAV, idiopathic double-positive AAV patients were older and had more severe anemia, lower Birmingham Vasculitis Activity Score (BVAS) and C-reactive protein (CRP) levels, less ear, nose, and throat (ENT) involvement, higher initial serum creatinine and a lower estimated glomerular filtration rate (eGFR) when compared with PR3-AAV (P < 0.05). The proportion of normal glomeruli of idiopathic double-positive AAV was the lowest among the three groups (P < 0.05). The idiopathic double-positive AAV patients had the worst remission rate (58.8%) among the three groups (P < 0.05). The relapse rate of double-positive AAV (40.0%) was comparable with PR3-AAV (44.8%) (P > 0.05). Although there was a trend toward a higher relapse rate of idiopathic double-positive AAV (40.0%) compared with MPO-AAV (23.5%), this did not reach statistical significance (P > 0.05). The proportion of patients who progressed to ESRD was 47.1% and 44.4% in the idiopathic double-positive AAV group and MPO-AAV group respectively, without statistical significance. Long-term patient survival also varied among the three groups (P < 0.05). Idiopathic double-positive AAV is a rare clinical entity with hybrid features of MPO-AAV and PR3-AAV. MPO-AAV is the “dominant” phenotype in idiopathic double-positive AAV.

Avacopan's potential to decrease MPO-ANCA titres concurrent with ameliorated activity in ANCA-associated vasculitis.

Avacopan, an orally administered C5a receptor antagonist, is effective in microscopic polyangiitis via the inhibition of neutrophil priming induced by C5a. However, the exact effect of avacopan on the production of myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) is yet to be clearly established. This report presents a microscopic polyangiitis patient without major organ damage where high levels of MPO-ANCA persisted with high-dose steroid therapy and azathioprine, but the addition of avacopan led to a reduction in MPO-ANCA titres. The present case implies that avacopan-mediated inhibition of C5a may lead to a reduction in MPO-ANCA levels, thereby potentially ameliorating the pathophysiology of ANCA-associated vasculitis. Nevertheless, the impact of avacopan on MPO-ANCA production cannot be asserted solely based on this report; therefore, further examination is necessary through subgroup analysis using data from larger-scale studies.

Latent class analysis of chest CT abnormalities to define subphenotypes in patients with MPO-ANCA-positive microscopic polyangiitis

BackgroundPatients with microscopic polyangiitis (MPA) and positive myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) may present with various abnormalities in chest computed tomography (CT). This study aimed to identify subphenotypes using latent class analysis (LCA) and to explore the relationship between the subphenotypes and clinical patterns, as well as compare the clinical characteristics of these subphenotypes in patients with MPO-ANCA-positive MPA (MPO-MPA). MethodsThe study identified subphenotypes using LCA based on chest CT findings in 178 patients with MPO-MPA and pulmonary involvement from June 2014 to August 2022. ResultsLCA identified 27 participants (15.2%) in class 1, 43 (24.1%) in class 2, 35 (19.7%) in class 3, and 73 (41.0%) in class 4. Class 1 was characterized by prominent inflammatory exudation, class 2 by fibrosis and architectural distortion, class 3 by predominantly bronchiectasis, and class 4 by lesions mixed with inflammation and fibrosis. Class 1 had the highest level of extrapulmonary disease activity, with 77.8% of patients experiencing diffuse alveolar hemorrhage. Class 2 had the lowest level of extrapulmonary disease activity, with 41.9% of patients showing usual interstitial pneumonia. Class 3 patients were more likely to have complications involving the ear, nose, and throat, as well as pulmonary infections before treatment, and they exhibited the best outcomes. The characteristics and outcomes of class 4 were intermediate among the four classes. ConclusionsThese findings suggest that bronchiectasis may represent a unique pattern of pulmonary involvement in MPO-MPA, highlighting the importance of screening for bronchiectasis in MPO-MPA and identifying optimal management strategies.

Clinical characteristics of hypertrophic cranial pachymeningitis in granulomatosis with polyangiitis: a retrospective single-center study in China.

Hypertrophic cranial pachymeningitis (HCP) is uncommon but a poorly understood complication of granulomatosis with polyangiitis (GPA). We conducted this retrospective study to elucidate the clinical characteristics and factors independently associated with granulomatosis with polyangiitis (GPA) complicated by hypertrophic cranial pachymeningitis (HCP) in China. We collected the medical records of 78 patients diagnosed with GPA who were admitted to the inpatient department of Peking Union Medical College Hospital between January 2003 and September 2021. Clinical features, laboratory and radiological findings, and Birmingham Vasculitis Activity Scores (excluding meningitis score) were recorded. A binary logistic regression analysis was performed to analyze factors independently associated with GPA-related HCP. Headache (100%) and cranial nerve palsy (61.5%) were common manifestations of HCP. Compared to 52 GPA patients without HCP, 26 patients with HCP required more time from initial symptoms to diagnosis, with a lower ratio of pulmonary and renal involvement, a higher ratio of myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) positivity, conductive or sensorineural hearing loss, mastoiditis, and decreased vision or sudden visual loss. Binary logistic regression analysis indicated that proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA) negativity (OR 10.698, p = 0.001), conductive or sensorineural hearing loss (OR 10.855, p = 0.005), and decreased vision or sudden visual loss (OR 8.647, p = 0.015) were significantly associated with GPA-related HCP. Of the 26 patients, 18 received methylprednisolone pulse treatment, and 18 received intrathecal injections of dexamethasone and methotrexate. HCP was a severe manifestation of GPA in our study. Independent factors associated with the occurrence of HCP in patients with GPA included PR3-ANCA negativity, conductive or sensorineural hearing loss, and decreased vision or sudden visual loss. Furthermore, GPA-related HCP was associated with higher disease activity, requiring more intensive treatments.

Garcin Syndrome in a Patient with Hypertrophic Pachymeningitis Following Otitis Media with Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis (OMAAV).

A 72-year-old Japanese woman presented to our hospital with progressive hearing loss and dysphagia. Blood tests revealed elevated C-reactive protein and myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA). Contrast-enhanced magnetic resonance imaging of the head showed hypertrophic pachymeningitis of the left middle cranial fossa with compression of the cranial nerves, including the trigeminal (V), facial (VII), glossopharyngeal (IX), and vagal (X) nerves, resulting in cranial nerve palsy. She was diagnosed with Garcin syndrome associated with otitis media with ANCA-associated vasculitis (OMAAV) and treated with high-dose glucocorticoid therapy followed by intravenous cyclophosphamide and rituximab. Therefore, OMAAV should be considered in the differential diagnosis of refractory otitis media with unilateral cranial nerve involvement.

Successful treatment for life threatening recurrent non-traumatic rectus sheath hematoma in a case with microscopic polyangiitis with rapidly progressive glomerulonephritis.

A 68-year-old woman was admitted to our hospital because of a rapid progression of renal dysfunction with positive myeloperoxidase antineutrophil cytoplasmic antibody and was diagnosed with rapidly progressive glomerulonephritis associated with microscopic polyangiitis (MPA). Severe right rectus sheath hematoma (RSH) bleeding from the inferior epigastric artery developed after starting hemodialysis, which required 4 transarterial embolizations due to recurrent bleeding. After additional treatment with methylprednisolone pulse therapy and rituximab, no rebleeding occurred. Although the giant hematoma reached the pelvis, it shrank spontaneously without any intervention. Nontraumatic RSH should therefore be considered when treating patients with multiple risk factors.

Impact of different ANCA serotypes on the long-term outcome of ANCA-associated vasculitis patients

Objectives To investigate the clinical features and long-term outcomes of Chinese anti-neutrophil cytoplasmic antibodies (ANCAs)-associated vasculitis (AAV) patients with different ANCA serotypes. Methods Two hundred and twenty-four AAV patients from January 2010 to June 2021 were divided into myeloperoxidase (MPO)-ANCA and proteinase 3 (PR3)-ANCA groups. Clinical and long-term outcomes were compared. Results In this study, the average follow-up was 46.4 months (range 0.3–188.4 months). One hundred and seventy-seven (79.0%) patients were MPO–ANCA-positive and 47 were PR3–ANCA-positive; the mean age of MPO–ANCA positive patients at diagnosis was elder than that of PR3–ANCA positive patients (67.0 vs. 60.0 years, p = .004). Among PR3–ANCA-positive patients, ear, nose and throat symptoms were more common (p = .014). Between two ANCA serotypes, there were no differences in complement 3 (C3), Birmingham vasculitis activity score (BVAS), five-factor score (FFS) or other organ involvements. For all AAV patients, the overall survival rates at one, three and five years were 80.0%, 67.0% and 56.4%, respectively. The cumulative relapse-free rates of one, three and five years were 89.5%, 76.4% and 68.4%, respectively. The survival of AAV patients was unaffected by the ANCA serotype (p = .23). The ANCA serotype also had no effect on either disease relapse (p = .20) or remission rates (p = .10). In our study, PR3–ANCA patients showed a better long-term survival, as the 5-year survival rate and the 5-year relapse-free survival rate of PR3–ANCA patients were 60.7% and 76.9%, while that of MPO–ANCA patients were 55.2% and 65.8%, respectively. Rather than ANCA serotype, younger patients with milder kidney involvement and lower disease assessment scores (BVAS and FFS) might be more relevant to better prognosis. Conclusions The likelihood of induced remission, patient survival or disease recurrence is all unaffected by ANCA serotypes. A better prognosis is seen in younger patients with milder kidney involvement and lower BVAS/FFS scores.

Features of diagnostic search in Churg–Strauss syndrome. Case report

Churg–Strauss syndrome is a rare systemic vasculitis affecting small-caliber vessels, which has characteristic clinical manifestations in the forms of allergic rhinosinusitis, bronchial asthma (BA), eosinophilia, and pulmonary infiltrates. The reason for late diagnostics is gradual manifestation of symptoms, that typical of systemic diseases. Improving the knowledge of pediatricians, pulmonologists about the role of diagnostic search in Churg–Strauss syndrome for further routing, monitoring and correction of patient therapy. A 17-year-old boy with BA was admitted to the pulmonology department for clarification, verification of the diagnosis, and selection of therapy. Instrumental and laboratory examination was carried out: on the computer tomography (CT) scan of the thoracic organs "migrating" infiltration of both lungs, based on laboratory data may correspond to eosinophilic zones. On the CT scan of the nasal sinuses polysinusitis, polyposis; external respiration function (spirography) – no pathology; myeloperoxidase-antineutrophil cytoplasmic antibodies (ANCA) – 14 U/ml (normal 5), anti-proteinase 3 anti-neutrophil ANCA – 30 U/ml (normal 5), anti-Saccharomyces cerevisiae antibodies – 6.3–7.2 U/ml, eosinophilia (12%, abs 840 c). The result of the level of antibodies was negative later. Churg–Strauss syndrome was based on the American College of Rheumatology criteria: BA, eosinophilia 10% (abs 840), rhinosinusitis, migrating infiltrations on CT scan. He was discharged for asthma combination therapy with high age doses of inhaled corticosteroids. After treatment his condition improved, there was no need for systemic corticosteroids. The described clinical case clearly demonstrates the difficulty and duration of diagnosing Churg–Strauss syndrome due to the stage-by-stage course of the disease, the frequent (33% of cases) absence of laboratory evidence of vasculitis (ANCA-neg.) significant difficulty of verifying the diagnosis at early stages. The diagnosis provides for a comprehensive and interdisciplinary approach to diagnosis and treatment.

Clinical Implication of Platelets and Complement C3 as Link Between Innate Immunity and the Coagulation System in ANCA-Associated Renal Vasculitis with Myeloperoxidase (MPO) ANCA Seropositivity

Clinical Implication of Platelets and Complement C3 as Link Between Innate Immunity and the Coagulation System in ANCA-Associated Renal Vasculitis with Myeloperoxidase (MPO) ANCA Seropositivity

Hypertrophic Pachymeningitis Associated with Myeloperoxidase-anti-neutrophil Cytoplasmic Antibodies Induced by Propylthiouracil: A Case Report.

A 71-year-old man with hyperthyroidism complained of headache lasting two months. He had been using propylthiouracil (PTU) for 14 years. Treatment intensification did not improve the symptoms. Blood tests detected a positive myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA). Diffuse dural thickening was identified by magnetic resonance imaging. The patient was diagnosed with hypertrophic pachymeningitis (HP) due to ANCA-associated vasculitis (AAV). He received methylprednisolone pulse therapy followed by prednisolone and methotrexate, which improved his headache. PTU-induced AAV-related HP is a rare and indiscernible disease. Therefore, the possibility of the disease should be proactively considered when a PTU user experiences refractory headaches.

Eosinophilic granulomatosis with polyangiitis developed after dupilumab administration in patients with eosinophilic chronic rhinosinusitis and asthma: a case report

BackgroundEosinophilic granulomatosis with polyangiitis (EGPA) is a form of anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis characterized by eosinophil-rich granulomatous inflammation and small-to-medium vessel vasculitis associated with asthma, rhinosinusitis, and eosinophilia. EGPA is often difficult to distinguish from severe asthma and eosinophilic chronic rhinosinusitis (ECRS) in cases when there are no findings that suggest vasculitis. Dupilumab, an anti-IL-4Rα monoclonal antibody, is expected to be effective in eosinophilic airway inflammatory diseases, such as refractory asthma and chronic rhinosinusitis (CRS). Although transient eosinophilia and eosinophilic pneumoniae have been reported in patients with refractory asthma and CRS associated with dupilumab, few studies have examined the development of EGPA.Case presentationWe report a case of a 61-year-old woman treated with dupilumab for refractory ECRS and eosinophilic otitis media (EOM) complicated by severe asthma. Although she had a previous history of eosinophilic pneumoniae and myeloperoxidase (MPO) ANCA positivity, there were no apparent findings of vasculitis before the initiation of dupilumab. After the second administration of dupilumab, several adverse events developed, including worsening of ECRS, EOM and asthma, and neuropathy. A blood test showed an eosoinophilia and re-elevation of MPO-ANCA levels after the administration of dupilumab. Therefore, dupilumab was discontinued owing to the development of EGPA, and prednisolone and azathioprine administration was initiated for a remission induction therapy.ConclusionTo the best of our knowledge, this is the first case report that suggests that dupilumab may directly trigger the manifestation of vasculitis in patients who were previously MPO-ANCA-positive. Although the precise mechanism of how dupilumab could trigger the development of EGPA requires further elucidation, measuring MPO-ANCA in patients with multiple eosinophilic disorders before the initiation of dupilumab might be helpful when considering the possibility of a latent EGPA. When administering dupilumab to patients with a previous history of MPO-ANCA positivity, clinicians must carefully monitor and collaborate with other specialists in the pertinent fields of study for appropriate usage.

Protein Profiling in Presymptomatic Individuals Separates Myeloperoxidase-Antineutrophil Cytoplasmic Antibody and Proteinase 3-Antineutrophil Cytoplasmic Antibody Vasculitides.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a chronic relapsing condition with unknown etiology. To gain insight into the molecular processes underlying the disease, we examined biomarkers in blood samples collected prior to symptom onset. The National Patient Register and Cause of Death register were searched for AAV-related International Classification of Diseases, Ninth Revision and Tenth Revision codes and linked to the registers from 5 biobanks. Eighty-five AAV patients with samples predating symptom onset of AAV were identified. For each case of AAV, 2 matched controls were included. Proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA expression levels were analyzed using enzyme-linked immunosorbent assays. Using an Olink Inflammation panel, 73 of 92 proteins were included after quality control. Data were replicated in a second cohort of 48 presymptomatic individuals and 96 controls. Of the 20 proteins with the lowest P values in the original cohort, 7 were replicated in the second cohort and 5 proteins were found to be significant between the groups in a meta-analysis. Eleven different pathways were identified in network enrichment analyses and were found to be significant in both cohorts. Stratification of samples obtained ≤5 years before symptom onset showed significant levels of CCL23, vascular endothelial growth factor A, and hepatocyte growth factor, which were also increased at borderline significant levels in the replication cohort (interleukin-6 was found to be significantly increased in the replication cohort). In presymptomatic AAV patients, 6 proteins were associated with MPO-ANCA positivity, and 7 proteins were associated with PR3-ANCA positivity. To our knowledge, this is the first study to identify protein markers preceding symptom onset in AAV patients. These findings set the stage for further research into the underlying cellular and molecular mechanisms in the pathogenesis of AAV and the diversification of patients into PR3-ANCA+ and MPO-ANCA+ subphenotypes.

317 Case of Goodpasture syndrome With Double-Positive Anti-Glomerular Basement Membrane (GBM) and Myeloperoxidase-Anti Neutrophil Cytoplasmic Antibodies (MPO-ANCA)

317 Case of Goodpasture syndrome With Double-Positive Anti-Glomerular Basement Membrane (GBM) and Myeloperoxidase-Anti Neutrophil Cytoplasmic Antibodies (MPO-ANCA)

Anti-glomerular Basement Membrane Disease Concomitant with MPO-ANCA Positivity Concurrent with High Serum Levels of Interleukin-26 Following Coronavirus Disease 2019 Vaccination.

As coronavirus disease 2019 (COVID-19) vaccine booster campaigns progress worldwide, new reports of complications following COVID-19 vaccination have emerged. We herein report a case of new-onset anti-glomerular basement membrane (GBM) disease concomitant with myeloperoxidase-antineutrophil cytoplasmic antibody positivity concurrent with high levels of interleukin (IL)-26 following the second dose of the Pfizer-BioNTech COVID-19 vaccine. The temporal association with vaccination in this case suggests that an enhanced neutrophilic immune response through IL-26 may have triggered necrotizing glomerulonephritis and a T-cell-mediated immune response to GBMs, leading to the development of anti-GBM antibodies, with an enhanced B-cell response after the vaccination triggering anti-GBM IgG and the onset of anti-GBM disease.