2020 international consensus on ANCA testing beyond systemic vasculitis

[Renal involvement in systemic diseases]

BACKGROUND

Diseases of the nonneoplastic renal parenchyma occur in the context of a number of disorders that affect the organism systemically and can thus represent a differential diagnosis for autoimmunological kidney diseases.

PURPOSE

Two common autoimmunologic diseases of the kidney, namely antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and systemic lupus erythematosus (SLE), are presented and put into context of the broader field of renal diseases. Novel diagnostic and therapeutic approaches are discussed.

MATERIALS AND METHODS

A review of the recent literature and an overview of the disease presentation are provided.

Monocentric study of IL-5 monoclonal antibody induction therapy for eosinophilic granulomatosis with polyangiitis

OBJECTIVE

Although sporadic case reports have demonstrated successful management of eosinophilic granulomatosis with polyangiitis (EGPA) by anti-IL-5 therapy, larger-scale monocentric studies for the efficacy of mepolizumab (MEP), an IL-5 monoclonal antibody, are still lacking in Taiwan.

METHODS

Hospitalized EGPA patients aged at least 18 years were enrolled from November 1998 to October 2023, and analyzed for demographic, clinical, laboratory, medication and outcome data, focusing on the efficacy and safety of biologics use, particularly induction therapy with MEP.

RESULTS

Twenty-seven EGPA patients aged 10-70 years (43 ± 15) at disease diagnosis were recruited with 21 under combined corticosteroids/cyclophosphamide induction therapy. Seventeen patients received biologics with 13 under MEP therapy. Ten patients aged 19-71 years (48 ± 15) completed 12-month induction therapy with a 100 mg quadri-weekly subcutaneous injection regimen indicated for active or relapse disease. There were reduced BVAS with complete remission in 6 and partial remission in 4 patients, lower CRP levels, decreased eosinophil counts with an inhibition of 92∼96 %, and tapered prednisolone dosages from 5 to 25 (13.0 ± 6.3) to 0-10 (3.3 ± 3.1) mg/day. Only one patient had an adverse event of injection site reactions. Nine patients received the same regimen for annual maintenance therapy. All had a persistent clinical remission. In these patients, 13-56 injections (41 ± 15) were prescribed with a follow-up period of 12∼52 months (38 ± 14).

CONCLUSION

In this retrospective study, induction therapy with a 12-month 100 mg MEP quadri-weekly subcutaneous injection regimen demonstrates the efficacy and safety for active and relapsing EGPA patients.

Renal Medullary Angiitis Associated with Cutaneous Leukocytoclastic Vasculitis

Renal medullary angiitis is characterized by interstitial hemorrhaging in the medulla with neutrophil infiltration. An 81-year-old man presented with a fever, kidney dysfunction, and purpura of the legs, which was diagnosed as leukocytoclastic vasculitis. Proteinase 3 antineutrophil cytoplasmic antibodies were weakly positive. A kidney biopsy showed severe tubulointerstitial hemorrhaging with neutrophilic infiltration in the perivascular areas surrounding the vasa recta in the medulla without crescent formation in the glomeruli. An immunofluorescence analysis was negative, and electron microscopy revealed no immune-dense deposits, ruling out immunoglobulin A vasculitis. Intravenous methylprednisolone for three days and plasma exchange followed by oral prednisolone improved his general condition.

ANCA-Positive Small-Vessel Vasculitis Following SARS-CoV-2 Vaccination-A Systematic Review

As vaccinations against the SARS-CoV-2 virus have become a crucial tool in controlling the spread of the disease, reports of rare health complications have emerged, including new-onset antineutrophil cytoplasmic autoantibodies (ANCA)-associated vasculitis (AAV). We systematically reviewed new-onset AAV following COVID-19 vaccination case reports and case series published in three databases before January 2024 following PRISMA guidelines to understand the characteristics of possible causal relationships or coincidences. In total, 404 articles were screened respectively by title, abstracts, and full-texts. Thirty-four papers fulfilled the inclusion criteria and have been analyzed, covering 44 patients with new-onset AAV after COVID-19 vaccination with no prior history of COVID-19 infection. Data regarding patients' metrics, comorbidities, vaccination characteristics, symptoms, diagnostics, treatment, and outcomes were investigated and summarized. The cohort consisted predominantly of females. AAV diagnosis was confirmed via biopsy, with renal dysfunction as a prevailing manifestation. In most cases, the first symptoms of AAV developed after the second dose; moreover, Pfizer-BioNTech was the most frequently administered vaccine among the analyzed cohort. Primary treatment involved glucocorticoid therapy, with a mostly favourable response. This systematic review aims to raise awareness among clinicians in the field regarding this rare but possible complication, to promote the prompt recognition and diagnosis of de novo ANCA-positive small-vessel vasculitis in timely association with SARS-CoV-2 vaccination.

Inflammatory bowel disease and risk of autoimmune hepatitis: A univariable and multivariable Mendelian randomization study

OBJECTIVE

This study aimed to use Mendelian randomization (MR) to investigate the potential causal association between inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH).

METHODS

Two-sample MR was performed to estimate the causal effect of IBD on AIH. The primary analysis employed the inverse variance weighted (IVW) method in univariable MR analysis, supplemented by additional methods including MR-Egger, weighted median, simple mode, and weighted mode. The p values were adjusted by FDR p-value adjustment. In the replication analysis, the primary IVW analysis was repeated and then pooled by meta-analysis. Sensitivity analyses were performed using Cochran's Q test, MR-Egger intercept test, MR-PRESSO, leave-one-out, and funnel plot analysis to evaluate the robustness of the MR findings. Additionally, multivariable MR (MVMR) was employed to estimate the direct causal effect of IBD on the risk of AIH.

RESULTS

In univariable MR analysis, a significant positive causal association was observed between IBD (both Crohn's disease (CD) or ulcerative colitis (UC)) and the risk of AIH (for CD and AIH, the IVW odds ratio (OR) = 1.10, 95% confidence interval (CI) = 1.00-1.16, P = 0.045, FDR P = 0.045; for UC and AIH, the IVW OR = 1.07, 95% CI = 1.00-1.13, P = 0.038, FDR P = 0.076). Furthermore, no significant positive correlation between IBD and the risk of AIH (OR = 1.13, 95% CI = 0.94-1.35, P = 0.194). Sensitivity analysis revealed no pleiotropic bias. MVMR analysis further confirmed the direct causal effect of CD or UC on the risk of AIH after adjusting for the common risk factors (cigarettes per day and osteoporosis). In the replication analysis, the positive causal association between UC and the risk of AIH remain significant (the IVW odds ratio (OR) = 1.32, 95% CI = 1.18-1.48, P = 2.90E-06). While no significant positive association was observed between CD or IBD and the risk of AIH in the replication analysis, a suggestive positive association between the identified risk factors (UC, CD, and IBD) and the risk of AIH was detected in the meta-analysis (OR = 1.09, 95% CI = 1.05-1.13, P<0.0001).

CONCLUSION

This MR study revealed a positive impact of the identified risk factors (CD, UC and IBD) on the risk of AIH within the European population.

Presentation and progression of MPO-ANCA interstitial lung disease

The association between MPO-ANCA-associated vasculitis (AAV) and interstitial lung disease (ILD) has been well established. Pulmonary fibrosis may coexist with, follow, or even precede the diagnosis of AAV, and its presence adversely affects the prognosis. The optimal approach to investigating ANCA in patients with ILD remains a subject of ongoing debate. Here we aim to describe presentation and progression of MPO-ANCA ILD. We conducted a retrospective evaluation of a cohort of individuals diagnosed with MPO-ANCA ILD, with or without accompanying renal impairment, at the Immunology and Cell Therapy Unit, Careggi University Hospital, Florence, Italy, between June 2016 and June 2022. Clinical records, imaging studies, pathologic examinations, and laboratory test results were collected. Among the 14 patients identified with MPO-ANCA ILD, we observed a significant association between MPO-ANCA titers assessed at the time of ILD diagnosis and renal involvement. Renal impairment in these cases often manifested as subclinical or slowly progressive kidney damage. Interestingly, complement C3 deposits were consistently found in all renal biopsy specimens, thereby suggesting the potential for novel therapeutic targets in managing renal complications associated with MPO-ANCA ILD. The presentation of MPO-ANCA vasculitis as ILD can be the first and only clinical manifestation. MPO-ANCA levels at ILD diagnosis could warn on the progression to renal involvement in patients with MPO-ANCA ILD, hence caution is needed because renal disease can be subclinical or smoldering.

Comparison of Interstitial Lung Disease Between Antineutrophil Cytoplasmic Antibodies Positive and Negative Patients: A Retrospective Cohort Study

OBJECTIVE

Positive antineutrophil cytoplasmic antibodies (ANCAs) may occur in the setting of interstitial lung disease (ILD), with or without ANCA-associated vasculitis (AAV). We aim to compare the characteristics and clinical course of patients with ILD and positive ANCA (ANCA-ILD) to those with negative ANCA.

METHODS

We performed a single-center retrospective cohort study from 2018 to 2021. All patients with ILD and ANCA testing were included. Patient characteristics (symptoms, dyspnea scale, and systemic AAV), test results (pulmonary high-resolution computed tomography and pulmonary function tests), and adverse events were collected from electronic medical records. Descriptive statistics and the Fisher exact test were used to compare the outcomes of patients with ANCA-ILD to those with ILD and negative ANCA.

RESULTS

A total of 265 patients with ILD were included. The mean follow-up duration was 69.3 months, 26 patients (9.8%) were ANCA positive, and 69.2% of those with ANCA-ILD had another autoantibody. AAV occurred in 17 patients (65.4%) with ANCA-ILD. In 29.4% of patients, AAV developed following ILD diagnosis. Usual interstitial pneumonia was the most common radiologic pattern in patients with ANCA-ILD. There was no association between ANCA status and the evolution of dyspnea, diffusing capacity of the lungs for carbon monoxide, and lung imaging. Forced vital capacity improved over time in 42% of patients with ANCA-ILD and in 17% of patients with negative ANCA (P = 0.006). Hospitalization occurred in 46.2% of patients with ANCA-ILD and in 21.8% of patients with negative ANCA (P = 0.006). Both groups had similar mortality rates.

CONCLUSION

Routine ANCA testing should be considered in patients with ILD. Patients with ANCA-ILD are at risk for AAV. More research is required to better understand and manage patients with ANCA-ILD.

Myeloperoxidase-specific antineutrophil cytoplasmic antibody-associated vasculitis

Myeloperoxidase (MPO)-specific antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (MPO-ANCA-associated vasculitis) is one of two major ANCA-associated vasculitis variants characterised by systemic necrotising vasculitis with few or no immune deposits. MPO-ANCA-associated vasculitis predominantly affects small blood vessels and, in contrast to its counterpart proteinase 3-ANCA-associated vasculitis, is generally not associated with granulomatous inflammation. The kidneys and lungs are the most commonly affected organs. The pathogenesis of MPO-ANCA-associated vasculitis is characterised by loss of tolerance to the neutrophil enzyme MPO. This loss of tolerance leads to a chronic immunopathological response where neutrophils become both the target and effector of autoimmunity. MPO-ANCA drives neutrophil activation, leading in turn to tissue and organ damage. Clinical trials have improved the therapeutic approach to MPO-ANCA-associated vasculitis. However, there remains substantial unmet need regarding relapse frequency, toxicity of current treatment, and long-term morbidity. In this Series paper, we present the current state of research regarding pathogenesis, diagnosis, and treatment of MPO-ANCA-associated vasculitis.

Interstitial lung diseases associated with ANCA positivity: A different disease spectrum from interstitial pneumonia with autoimmune features

BACKGROUND

Anti-neutrophil cytoplasmic antibody (ANCA) is a type of autoantibodies associated with vasculitis. ANCA positivity is commonly observed in interstitial lung disease (ILD) patients. 7%-10% of ANCA-positive ILD patients don't present any symptoms of systemic vasculitis and are termed ANCA-positive idiopathic interstitial pneumonia (ANCA-IIP). Some researchers propose that ANCA-IIP should be categorized as interstitial pneumonia with autoimmune features (IPAF), although the official ATS/ERS statements exclude ANCA-IIP from this classification. Whether ANCA-IIP should be categorized into the entity of IPAF is still debatable.

METHODS

Patients diagnosed with ANCA-IIP and those with IPAF were analyzed in a retrospective study of ILD. The clinical outcomes were determined through pulmonary function tests (PFTs) after a one-year follow-up, as well as assessing all-cause mortality.

RESULTS

27 patients with ANCA-IIP and 143 patients with IPAF were analyzed from a cohort of 995 patients with ILD. Patients in the ANCA-IIP group had an older age and a high proportion of males compared to those in the IPAF group. PFT results at baseline were similar between the two groups, except for a better FEV1% in the ANCA-IIP group. Glucocorticoid and immunosuppressive therapy improved pulmonary function in patients with IPAF, but it continued to deteriorate after one year of treatment in the ANCA-IIP group. Furthermore, the all-cause mortality rate was significantly higher in the ANCA-IIP group than in the IPAF group (22.2% vs. 6.3%, P = 0.017).

CONCLUSION

The responses to glucocorticoid and immunosuppressive therapy differ between the ANCA-IIP and IPAF groups, leading to divergent prognoses. Therefore, it is inappropriate to classify ANCA-IIP as part of IPAF.

Occlusive cutaneous vasculopathies as cause of chronic ulcers

The term occluding vasculopathies covers a large number of different conditions. These often manifest as skin ulcers. Occluding vasculopathies should be considered in the differential diagnosis of leg ulcers. The term "occlusive vasculopathies" encompasses pathophysiologically related entities that share structural or thrombotic obliteration of small cutaneous vessels. In this article, we will focus on livedoid vasculopathy with and without antiphospholipid syndrome and calciphylaxis with differentiation from hypertonic leg ulcer as the most relevant differential diagnoses of leg ulcer. The term also includes vascular occlusion, for example due to oxalate or cholesterol embolism, and septic vasculopathy. This often leads to acral ulceration and is therefore not a differential diagnosis with classic leg ulcers. It will not be discussed in this article. Occlusive vasculopathy may be suspected in the presence of the typical livedo racemosa or (non-inflammatory) retiform purpura as a sign of reduced cutaneous perfusion in the wound area. Inflammatory dermatoses, especially vasculitides, must be differentiated. This is achieved by histopathological evaluation of a tissue sample of sufficient size and depth taken at the appropriate time. In addition, specific laboratory parameters, particularly coagulation parameters, can support the diagnosis.

Okkludierende kutane Vaskulopathien als Ursachen chronischer Unterschenkelulzerationen

Unter den Begriff der okkludierenden Vaskulopathien fällt eine Reihe unterschiedlicher Krankheitsbilder. Diese manifestieren sich an der Haut häufig mit Ulzerationen. Gerade bei Ulzerationen der Unterschenkel sollten okkludierende Vaskulopathien in die differenzialdiagnostischen Überlegungen einbezogen werden. Der Begriff „okkludierende Vaskulopathien“ umfasst pathophysiologisch verwandte Entitäten, die eine strukturelle oder thrombotische Obliteration von kleinsten Hautgefäßen gemein haben. In diesem Artikel wird vor allem auf die Livedovaskulopathie mit und ohne Antiphospholipidsyndrom sowie die Calciphylaxie mit Abgrenzung zum Ulcus cruris hypertonicum als die relevantesten Differenzialdiagnosen von Unterschenkelulzerationen eingegangen. Der Begriff umfasst auch Gefäßverschlüsse, beispielsweise durch Oxalat oder Cholesterinembolie, sowie die septische Vaskulopathie. Diese führt häufig zu akralen Ulzerationen und stellt somit keine Differenzialdiagnose zum klassischen Ulcus cruris dar. Sie wird daher in diesem Artikel nicht behandelt.

Der Verdacht einer okkludierenden Vaskulopathie kann über die typische Livedo racemosa beziehungsweise die (nichtinflammatorische) retiforme Purpura als Zeichen der kutanen Minderdurchblutung in der Wundumgebung gestellt werden. Entzündliche Dermatosen, insbesondere Vaskulitiden, müssen differenzialdiagnostisch abgegrenzt werden. Dies geschieht zum Teil klinisch und durch die histopathologische Beurteilung einer Gewebeprobe, die in ausreichender Größe und Tiefe sowie zum richtigen Zeitpunkt entnommen werden muss. Ergänzend können spezifische Laborparameter, insbesondere die Gerinnungsdiagnostik, die Diagnosestellung unterstützen.

Verification, implementation and harmonization of automated chemiluminescent immunoassays for MPO- and PR3-ANCA detection

OBJECTIVES

Antineutrophil cytoplasmic antibody (ANCA) testing assists clinicians diagnose ANCA-associated vasculitis (AAV). We aimed to verify and harmonize chemiluminescent immunoassays for the detection of myeloperoxidase (MPO)- and proteinase 3 (PR3)-ANCA.

METHODS

An in-house ELISA, a capture ELISA, and a chemiluminescent assay QUANTA Flash on a BIO-FLASH analyzer were used to detect MPO- and PR3-ANCA in sera from 39 patients with AAV, 55 patients with various non-AAV, and 66 patients with connective tissue diseases. The results of the assays were evaluated, and their clinical performance was assessed. The precision and linearity of the QUANTA Flash assays were determined, and likelihood ratios (LRs) for AAV at diagnosis were calculated.

RESULTS

The precision and linearity of the QUANTA Flash assays were confirmed. Overall agreement between 97.5 and 98.8 % and Cohen's kappa coefficients between 0.861 and 0.947 were observed for the results of the QUANTA Flash assays and ELISAs. The diagnostic sensitivity, specificity, and ROC analysis of the assays for AAV were statistically similar (in-house ELISA 89.7 %, 95.0 %, and 0.937; capture ELISA 92.3 %, 98.3 %, and 0.939; and QUANTA Flash 89.7 %, 95.9 %, and 0.972). For the QUANTA Flash assay results, the interval-specific LRs for AAV at diagnosis were: 0-8 CU had LR 0.08, 8-29 CU had LR 1.03, 29-121 CU had LR 7.76, 121-191 CU had LR 12.4, and >191 CU had LR ∞.

CONCLUSIONS

The QUANTA Flash MPO and PR3 assays provide precise and consistent results and have comparable clinical utility for AAV. The calculated LRs were consistent with published LRs, confirming the utility of LRs for harmonization of ANCA results.

Diagnosis and management of ANCA-associated vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis consists of two main diseases, granulomatosis with polyangiitis and microscopic polyangiitis, and remains among the most devastating and potentially lethal forms of autoimmune inflammatory disease. Granulomatosis with polyangiitis and microscopic polyangiitis are characterised by a necrotising vasculitis that can involve almost any organ, and have generally been studied together. The diseases commonly affect the kidneys, lungs, upper respiratory tract, skin, eyes, and peripheral nerves. Granulomatous inflammation and multinucleated giant cells are key pathological hallmarks of granulomatosis with polyangiitis, but are absent in microscopic polyangiitis. Many immune system events are essential to disease aetiopathogenesis, such as activation of the alternative complement pathway, neutrophil activation via complement receptors, and the influx of inflammatory cells, including monocytes and macrophages. These cells perpetuate inflammation and lead to organ damage. During the 21st century, the management of ANCA-associated vasculitis has moved away from reliance on cytotoxic medications and towards targeted biological medications for both the induction and maintenance of disease remission. Earlier diagnosis, partly the result of more reliable ANCA testing, has led to improved patient outcomes and better survival. Reductions in acute disease-related mortality have now shifted focus to long-term morbidities related to ANCA-associated vasculitis and their treatments, such as chronic kidney disease and cardiovascular disease. Therapeutic approaches in both clinical trials and clinical practice still remain too reliant on glucocorticoids, and continued efforts to reduce toxicity from glucocorticoids remain a priority in the development of new treatment strategies.

EULAR recommendations for the management of ANCA-associated vasculitis: 2022 update

BACKGROUND

Since the publication of the EULAR recommendations for the management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in 2016, several randomised clinical trials have been published that have the potential to change clinical care and support the need for an update.

METHODS

Using EULAR standardised operating procedures, the EULAR task force undertook a systematic literature review and sought opinion from 20 experts from 16 countries. We modified existing recommendations and created new recommendations.

RESULTS

Four overarching principles and 17 recommendations were formulated. We recommend biopsies and ANCA testing to assist in establishing a diagnosis of AAV. For remission induction in life-threatening or organ-threatening AAV, we recommend a combination of high-dose glucocorticoids (GCs) in combination with either rituximab or cyclophosphamide. We recommend tapering of the GC dose to a target of 5 mg prednisolone equivalent/day within 4-5 months. Avacopan may be considered as part of a strategy to reduce exposure to GC in granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA). Plasma exchange may be considered in patients with rapidly progressive glomerulonephritis. For remission maintenance of GPA/MPA, we recommend rituximab. In patients with relapsing or refractory eosinophilic GPA, we recommend the use of mepolizumab. Azathioprine and methotrexate are alternatives to biologics for remission maintenance in AAV.

CONCLUSIONS

In the light of recent advancements, these recommendations provide updated guidance on AAV management. As substantial data gaps still exist, informed decision-making between physicians and patients remains of key relevance.

Overlapping systemic lupus erythematosus, seropositive erosive rheumatoid arthritis, and ANCA-associated vasculitis: A case report and literature review

The overlap of rheumatoid arthritis and systemic lupus erythematosus is well described, with a syndrome known as 'rhupus'. ANCA-associated vasculitis, however, is uncommonly associated with other autoimmune conditions. Here, we present a case of lupus, rheumatoid arthritis, and ANCA-associated vasculitis, with significant time elapsed between presentations, resulting in an accumulation of the three diagnoses over the course of 35 years. The patient was diagnosed with lupus at age 45, presenting with inflammatory polyarthritis, thrombocytopenia, leukopenia, positive ANA, positive anti-DNA, and hypocomplementemia. She was maintained on hydroxychloroquine therapy with minimal disease activity. Approximately 20 years later, she had a flare of polyarthritis with bilateral wrist erosive arthropathy and a positive rheumatoid factor, diagnosed as rheumatoid arthritis. Anti-TNFα therapy was initiated, and she was stable for a further 10 years. At age 79, she developed ANCA-associated vasculitis AAV with pulmonary and renal manifestations, treated with rituximab induction therapy and steroids. She recovered and her MPO-ANCA titre normalised. One year later, off the anti-TNFα, she again experienced an acute kidney injury with a repeat rise in MPO-ANCA. She was re-induced and maintained on steroids and rituximab. This novel case highlights the range of possible overlap syndromes, as well as how multiple autoimmune diagnoses can evolve over decades in previously stable disease. There is growing work around polyautoimmunity with ANCA-associated vasculitis and other systemic autoimmune diseases, which has potential to identify common aetiologies and pathogenesis. Knowledge of these overlap syndromes can help to recognise and manage these conditions in a timely manner.

The Role of Neutrophils in ANCA-Associated Vasculitis: The Pathogenic Role and Diagnostic Utility of Autoantibodies

Recent years have brought progress in understanding the role of the neutrophil, dispelling the dogma of homogeneous cells mainly involved in the prime defence against pathogens, shedding light on their pathogenic role in inflammatory diseases and on the importance of antineutrophil-cytoplasmic antibodies' pathogenic role in ANCA-associated vasculitides vasculitis (AAV). Myeloperoxidase (MPO) and proteinase 3 (PR3) expressed in neutrophil granulocytes are the most common targets for ANCAs and contribute to the formation of MPO-ANCAs and PR3-ANCAs which, released to the bloodstream, become an excellent diagnostic tool for AAV. In this study, we focus on increasing the clinical and experimental evidence that supports the pathogenic role of ANCAs in AAV. Additionally, we discuss the diagnostic utility of ANCAs for disease activity and prognosis in AAV. Understanding the central role of ANCAs in AAV is crucial for advancing our knowledge of these complex disorders and developing targeted therapeutic strategies in the era of personalized medicine.

The significant IgG4 infiltrate in autoimmune hepatitis is associated with a greater ductular reaction and more advanced liver disease

BACKGROUND

Sclerosing cholangitis is the typical IgG4-related disease digestive involvement. However, the role of the IgG4 liver expression in autoimmune hepatitis remains unknown.

AIMS

to assess whether the expression of IgG4 plasma cells in patients with autoimmune hepatitis (AIH) was associated with different outcomes.

METHODS

Retrospective study including patients diagnosed with AIH by biopsy from January-2009 to June-2021. At least mild IgG4 expression (>10 IgG4+-plasma cells per field) was considered as significant.

RESULTS

85 patients with AIH were included. Overall, 58.8% were women, mean age 54 years. Nine (10.6%) presented cirrhosis at diagnosis. Fifteen (17.6%) had significant IgG4 liver expression. Patients with IgG4 infiltrate were older (p = 0.021), presented liver cirrhosis more frequently (33.3% vs. 5.7%, p = 0.007), greater IgG plasma values (p = 0.008) and atypical ANCAs (p = 0.086); ductular reaction was also more common (p = 0.009). Complete remission rate was similar regardless of the IgG4 infiltrate. Time to corticosteroids discontinuation was longer in subjects with IgG4 infiltrate (p = 0.068), but second-line therapy tended to be less frequent (p = 0.187).

CONCLUSION

Significant IgG4 liver infiltrate in patients with autoimmune hepatitis is associated with more advanced liver disease. The greater ductular reaction mediated by the IgG4 infiltrate may be the cause for this finding, though this finding should be prospectively assessed.

Interference of anti-nuclear antibodies on determination of anti-neutrophil cytoplasmic antibodies in patients suspected of vasculitis: a case series

Anti-neutrophil cytoplasmic antibodies (ANCA) are mainly associated with medium and small vessel vasculitis. Two main methodologies currently available for detection of these antibodies are indirect immunofluorescence (IIF) and monospecific proteinase 3 (PR3) and myeloperoxidase (MPO) based immunoassays. However, well-defined guidelines regarding mode of testing for ANCA in laboratories still don't exist, leading to problems in diagnosis and further patient management. Anti-neutrophil cytoplasmic antibodies testing by IIF and enzyme linked immunosorbent assay (ELISA) often pose a significant challenge in diseases other than vasculitis and in overlapping autoimmune conditions. Anti-neutrophil cytoplasmic antibodies reporting by IIF can be challenging in certain circumstances. This case series aims to discuss four cases with probable interference of anti-nuclear antibodies (ANA) during ANCA testing by IIF resulting in ANCA false positivity. All four cases on subsequent reflex testing by line immunoassay (LIA) for PR3, MPO and glomerular basement membrane (GBM) antigens proved otherwise. While analysing for the presence of ANCA by IIF, the possible interference of ANA leading to a false positive ANCA result should be kept in mind and alternative methods of testing like ELISA, extended granulocyte based IIF assays with MPO and PR3 coated beads, etc., should also be advised. Probability of atypical ANCA in diseases other than vasculitis should also be considered in case of ambiguous results.

Autoantibodies in COVID-19, a possible role in the pathogenesis of the disease

OBJECTIVES

In this study, we investigated whether SARS-CoV-2 stimulates autoantibody production.

METHODS

The study included 91 patients hospitalized due to COVID 19, with no previous history of immunological diseases. Immunofluorescence assays were performed to detect antinuclear antibodies (ANAs) and antineutrophil cytoplasmic antibodies (ANCAs), along with tests for specific autoantibodies.

RESULTS

The median age (57% male) was 74 years (range 38-95 years). Autoantibodies were positive in 67 (74%), ANA in 65 (71%), and ANCA in 11 (12%) patients. Female gender (p = 0.01), age (p = 0.005), and Charlson comorbidity index (p = 0.004) were significant predictors for the development of ANA/ANCA antibodies (p = 0.004). Nuclear mitotic apparatus (NuMA)-like, positivity was the strongest predictor of acute kidney injury (AKI), together with noninvasive ventilation and eGFR (χ2  = 49.01, P < 0.001).

CONCLUSION

Positive autoantibodies in a large proportion of patients suggest a role of autoimmunity in the pathophysiology of acute COVID-19 disease. NuMA was the strongest predictor of AKI.

Rat bite fever mimicking ANCA-associated vasculitis

Rat bite fever (RBF) is a rare infectious zoonotic disease caused by two bacterial species: the Gram-negative rod Streptobacillus moniliformis and the Gram-negative coiled rod Spirillum minus. The association between RBF and skin vasculitis and arthritis has been observed. The aim of this paper was to present a case of rat-bite fever with symptoms of skin vasculitis and arthritis, associated with high titers of ANCA antibodies and anti-endothelial cell antibodies suggestive of primary vasculitis. The patient was successfully treated with antibiotics and non-steroidal anti-inflammatory drugs, leading to significant improvement. Based on the presented case, we discuss the differential diagnosis of the signs and the role of infection in the induction of ANCA antibodies. We reviewed the English language literature for cases of RBF presenting with symptoms of vasculitis and/or antibody presence. A literature review was performed in PubMed and Google using the keywords "rat bite fever" AND "vasculitis", "systemic vasculitis", "ANCA", "antiendothelial antibodies". No cases of rat-bite fever with the presence of ANCA antibodies or AECA antibodies in its course have been described thus far. Rat bite fever is a rare disease with nonspecific symptoms. In its course, general weakness, intermittent fever, leukocytoclastic vasculitis, and arthritis are reported. To our knowledge, this is the first reported case of ANCA positivity associated with RBF.

Traditional and Disease-Specific Risk Factors for Cardiovascular Events in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: A Multinational Retrospective Study

OBJECTIVE

To investigate the occurrence of cardiovascular events (CVEs) in a large cohort of patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) across the European Union, China, Turkey, Russia, the United Kingdom, and the USA.

METHODS

Patients with a definite diagnosis of AAV who were followed for ≥ 3 months and had sufficient documentation were included. Data on myocardial infarction (MI) and stroke were collected retrospectively from tertiary vasculitis centers. Univariate and multivariate Cox regression models were used to estimate hazard ratios (HRs) and 95% CIs.

RESULTS

Over a median follow-up of 62.0 months (IQR 22.6-100.0), CVEs (mostly MIs) occurred in 245 (10.7%) of 2286 patients with AAV, with a higher frequency in China and the UK. On multivariate regression analysis, older age (55-64.9 yrs, HR 2.93, 95% CI 1.99-4.31), smoking (HR 1.98, 95% CI 1.48-2.64), Chinese origin (HR 4.24, 95% CI 3.07-5.85), and pulmonary (HR 1.50, 95% CI 1.09-2.06) and kidney (HR 3.02, 95% CI 2.08-4.37) involvement were independent variables associated with a higher occurrence of CVEs.

CONCLUSION

We showed that geographic region and both traditional and disease-specific (kidney involvement in particular) factors were independently associated with CVEs. Proper assessment and management of modifiable cardiovascular (CV) risk factors are essential for prevention of CV morbidity in patients with AAV.

Inflammation, Autoinflammation and Autoimmunity in Inflammatory Bowel Diseases

In this review, the role of innate and adaptive immunity in the pathogenesis of inflammatory bowel diseases (IBD) is reported. In IBD, an altered innate immunity is often found, with increased Th17 and decreased Treg cells infiltrating the intestinal mucosa. An associated increase in inflammatory cytokines, such as IL-1 and TNF-α, and a decrease in anti-inflammatory cytokines, such as IL-10, concur in favoring the persistent inflammation of the gut mucosa. Autoinflammation is highlighted with insights in the role of inflammasomes, which activation by exogenous or endogenous triggers might be favored by mutations of NOD and NLRP proteins. Autoimmunity mechanisms also take place in IBD pathogenesis and in this context of a persistent immune stimulation by bacterial antigens and antigens derived from intestinal cells degradation, the adaptive immune response takes place and results in antibodies and autoantibodies production, a frequent finding in these diseases. Inflammation, autoinflammation and autoimmunity concur in altering the mucus layer and enhancing intestinal permeability, which sustains the vicious cycle of further mucosal inflammation.

Coexistence of cryoglobulinemia and ANCA-associated vasculitis in a chronic brucellosis patient -a case report and literature review

BACKGROUND

The renal involvement of brucellosis is not common. Here we reported a rare case of chronic brucellosis accompanied by nephritic syndrome, acute kidney injury, the coexistence of cryoglobulinemia and antineutrophil cytoplasmic autoantibodies (ANCA) associated vasculitis (AAV) superimposed on iliac aortic stent implantation. The diagnosis and treatment of the case are instructive.

CASE PRESENTATION

A 49-year-old man with hypertension and iliac aortic stent implantation was admitted for unexplained renal failure with signs of nephritic syndrome, congestive heart failure, moderate anemia and livedoid change in the left sole with pain. His past history included chronic brucellosis and he just underwent the recurrence and completed the 6 weeks of antibiotics treatment. He demonstrated positive cytoplasmic/proteinase 3 ANCA, mixed type cryoglobulinemia and decreased C3. The kidney biopsy revealed endocapillary proliferative glomerulonephritis with a small amount of crescent formation. Immunofluorescence staining revealed only C3-positive staining. In accordance with clinical and laboratory findings, post-infective acute glomerulonephritis superimposed with AAV was diagnosed. The patient was treated with corticosteroids and antibiotics and sustained alleviation of renal function and brucellosis was achieved during the course of a 3-month follow-up.

CONCLUSIONS

Here we describe the diagnostic and treatment challenge in a patient with chronic brucellosis related glomerulonephritis accompanied by the coexistence of AAV and cryoglobulinemia. Renal biopsy confirmed the diagnosis of postinfectious acute glomerulonephritis overlapping with ANCA related crescentic glomerulonephritis, which was not ever reported in the literature. The patient showed a good response to steroid treatment which indicated the immunity-induced kidney injury. Meanwhile, it is essential to recognize and actively treat the coexisting brucellosis even when there are no clinical signs of the active stage of infection. This is the critical point for a salutary patient outcome for brucellosis associated renal complications.

[Consensus guideline on the interdisciplinary diagnosis of interstitial lung diseases]

The evaluation of a patient with interstitial lung disease (ILD) includes assessment of clinical, radiological, and often histopathological data. As there were no specific recommendations to guide the evaluation of patients under the suspicion of an ILD within the German practice landscape, this position statement from an interdisciplinary panel of ILD experts provides guidance related to the diagnostic modalities which should be used in the evaluation of ILD. This includes clinical assessment rheumatological evaluation, radiological examinations, histopathologic sampling and the need for a final discussion in a multidisciplinary team.

Oral manifestations of anti-neutrophil cytoplasmic antibody-associated vasculitis: an update and narrative review of the literature

Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is a multisystem disorder of small blood vessels subdivided into granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Oral manifestations (OMs) have been reported to include mucosal ulceration, gingival enlargement, alveolar bone necrosis, tooth loss, oro-antral communication, palatal perforation, parotitis, and candidal infection mainly in GPA. They may appear during the course of the disease, as a disease flare-up, or as the presenting sign. These OMs are often nonspecific and can mimic an array of conditions, therefore formulating a differential diagnosis can be challenging. This review updates the OMs of GPA, and, for the first, time includes OMs of other AAVs. It provides recommendations for the overall assessment and the diagnosis and management of all AAV OMs with considerations for treatment coordination. The role of oral health care providers in multidisciplinary care is highlighted.

Cardiac involvement and cardiovascular risk factors in pediatric primary systemic vasculitides

Pediatric primary systemic vasculitides are a complex group of diseases. Vasculitis subgroups are mainly determined according to the size of the predominantly affected vessels. In patients with primary systemic vasculitis, the location of vascular involvement, the size of the vessels, the extent of vascular damage, and the underlying pathology determine the disease phenotype and severity. Cardiac involvement is rare in some pediatric vasculitis, such as IgA vasculitis and polyarteritis nodosa, while it is more common in some others like Kawasaki disease and Takayasu arteritis. On the other hand, chronic inflammation in the setting of systemic vasculitis forms a major cardiovascular risk factor. Accelerated atherosclerosis and the tendency to thrombosis are the main issues determining the cardiovascular risks in pediatric systemic vasculitis. Early diagnosis and treatment are essential in these patients to minimize morbidity and mortality. In this review, we aimed to raise physicians' awareness of cardiac involvement and cardiovascular risks in pediatric patients with primary systemic vasculitis.

Reclassification of previously diagnosed GPA patients using the 2022 ACR/EULAR classification criteria

OBJECTIVES

This study applied the 2022 criteria for granulomatosis with polyangiitis (GPA) proposed by the ACR and EULAR (the 2022 ACR/EULAR criteria) to Korean patients with previously diagnosed GPA to investigate the number of patients who could be reclassified as having GPA.

METHODS

Sixty-five patients with GPA, who met the 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides and the 2007 European Medicines Agency algorithm for GPA, were included in this study. They were reclassified based on the 2022 ACR/EULAR criteria.

RESULTS

Of the 65 patients, 48 patients (73.8%) were reclassified as having GPA. A patient could not be reclassified as having GPA if the patient did not have a total score of 5 despite granulomas on biopsy or clear GPA surrogate markers. Among the 17 patients unclassified as having GPA, 16 patients were reclassified as having MPA and one as having unclassifiable vasculitis, and furthermore, 94.1% of them harboured MPO-ANCA (or perinuclear (P)-ANCA).

CONCLUSION

The concordance rate between the 2022 ACR/EULAR criteria for GPA and the previous criteria in patients with previously diagnosed GPA was 73.8%. Although the 2022 ACR/EULAR criteria are the product of the most advanced methodologic process, it should be noted that there were some consequences of distorting the CHCC definition, and further discussion is required, especially with respect to the weightage of the items.

[Autoimmune diagnostics in gastroenterology and hepatology]

Autoimmune diseases may affect all parts of the gastrointestinal system and the liver. Autoantibodies can be very helpful in the diagnosis of these diseases. For detection, two main diagnostic techniques are available: indirect immunofluorescence technique (IFT) as well as solid phase assays as e. g. ELISA or immunoblot. Depending on symptoms and differential diagnosis, IFT may serve as screening assay and solid phase assays may serve as confirmatory assays. The esophagus can sometimes be affected by systemic autoimmune diseases; diagnosis is often facilitated by the proof of circulating autoantibodies. Atrophic gastritis is the most prominent autoimmune disease of the stomach also displaying circulating autoantibodies. Antibody diagnosis for celiac disease has been implemented in all common guidelines. For liver and pancreatic autoimmune diseases, there is a solid history for the significance of the detection of circulating autoantibodies. Knowledge of available tests and accurate implementation accelerates correct diagnosis in many cases.

Pharmacological profile of mepolizumab

An elevated number of eosinophils have been implicated in several type 2 inflammatory chronic diseases that occur at various sites in the body. Over the past 20 years, our knowledge of diseases associated with increased numbers of eosinophils has advanced thanks to the development of drugs that can reduce or even eliminate eosinophils. One such agent is mepolizumab, a humanized monoclonal antibody that binds to interleukin -5 (IL-5). This article briefly and clearly summarizes the pharmacological profile of mepolizumab and its current indications for a number of chronic eosinophilic diseases.

Clinical significance of acute exacerbation in interstitial lung disease with antineutrophil cytoplasmic antibody: an indicator of poor prognosis

BACKGROUND

The association between interstitial lung disease (ILD) and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has been increasingly recognized in recent years. The clinical features and prognostic differences between AAV-associated ILD and isolated ANCA-positive idiopathic interstitial pneumonias (IIPs) remain unclear. The purpose of this study was to determine the clinical significance and prognosis of ANCA-positive ILD to further guide clinical management.

METHODS

This study retrospectively reviewed the data of 379 ILD patients with available ANCA results and ultimately analysed 49 ANCA-positive patients. AAV diagnosis was based on the 2012 revised Chapel Hill Consensus Conference (CHCC) criteria, and 33 of 49 patients were diagnosed with microscopic polyangiitis (MPA). The baseline clinical information and laboratory parameters were collected and analysed at each patient's initial diagnosis.

RESULTS

Among 49 ANCA-positive ILD patients, the high-resolution computed tomography (HRCT) pattern was mainly usual interstitial pneumonia (UIP) (59.18%), followed by nonspecific interstitial pneumonia (NSIP) (26.53%). The C-reactive protein (CRP) level (43.89± 40.61 versus 18.74± 20.05, p = 0.028) and erythrocyte sedimentation rate (ESR) (71.97± 42.73 versus 40.69± 28.46, p = 0.011) were significantly higher in the MPA-ILD group than in the ANCA-IIP group. Haemoglobin (113.09 ± 24.47 versus 132.19± 13.34, p = 0.006) and albumin (32.95± 5.84 versus 36.52± 3.94, p = 0.032) levels were significantly lower. Survival was shorter among MPA-ILD patients than among ANCA-IIP patients [hazard ratio (HR) 3.38, 95% confidence interval (CI) 1.32-8.67, p = 0.040]. In the multivariable Cox analysis, a diagnosis of MPA (HR 3.91, 95% CI 1.07-14.08, p = 0.038) and acute exacerbation (AE) of ILD (HR 9.43, 95% CI 2.89-30.30, p < 0.001) were significantly independently associated with shorter survival in ANCA-positive ILD patients, and the NSIP pattern (HR 0.07, 95% CI 0.01-0.41, p = 0.003) was independently associated with prolonged survival.

CONCLUSION

ANCA-ILD patients mostly have myeloperoxidase (MPO)-ANCA positivity and an MPA diagnosis. Survival was shorter among MPA-ILD patients than among ANCA-IIP patients. Respiratory failure and AE were associated with poorer prognosis. Early antifibrotic treatment may be a reasonable treatment option in fibrotic ILD patients with ANCA positivity.

The neutrophil: A key resourceful agent in immune‐mediated vasculitis

The term "vasculitis" refers to a group of rare immune-mediated diseases characterized by the dysregulated immune system attacking blood vessels located in any organ of the body, including the skin, lungs, and kidneys. Vasculitides are classified according to the size of the vessel that is affected. Although this observation is not specific to small-, medium-, or large-vessel vasculitides, patients show a high circulating neutrophil-to-lymphocyte ratio, suggesting the direct or indirect involvement of neutrophils in these diseases. As first responders to infection or inflammation, neutrophils release cytotoxic mediators, including reactive oxygen species, proteases, and neutrophil extracellular traps. If not controlled, this dangerous arsenal can injure the vascular system, which acts as the main transport route for neutrophils, thereby amplifying the initial inflammatory stimulus and the recruitment of immune cells. This review highlights the ability of neutrophils to "set the tone" for immune cells and other cells in the vessel wall. Considering both their long-established and newly described roles, we extend their functions far beyond their direct host-damaging potential. We also review the roles of neutrophils in various types of primary vasculitis, including immune complex vasculitis, anti-neutrophil cytoplasmic antibody-associated vasculitis, polyarteritis nodosa, Kawasaki disease, giant cell arteritis, Takayasu arteritis, and Behçet's disease.

Characteristics and Diagnostic Challenge of Antineutrophil Cytoplasmic Antibody Positive Infective Endocarditis

OBJECTIVE

Antineutrophil cytoplasmic antibody (ANCA) has been reported in patients with infective endocarditis. Whether ANCA is associated with certain characteristics of infective endocarditis is unclear. The principal aim of this study is to investigate the clinical implications of ANCA in infective endocarditis and highlight the diagnostic challenge in ANCA-positive patients with infective endocarditis.

METHODS

A retrospective study was conducted in a tertiary hospital in China from August 2012 to December 2021. Patients with a diagnosis of infective endocarditis and available ANCA results were included in the study. The clinical and pathological characteristics were compared between ANCA-positive and ANCA-negative patients.

RESULTS

A total of 237 patients were included. Forty three (18.1%) were ANCA-positive, predominantly c-ANCA/anti-PR3. Compared to ANCA-negative patients, ANCA-positive patients had longer disease duration (P = .004), more frequent purpura (P = .015), macrohematuria (P = .002), proteinuria (P = .043), acute kidney injury (P = .004), and rapidly progressive glomerulonephritis (P = .010). Histologic findings of 8 patients with infective endocarditis-associated glomerulonephritis were reviewed. Two ANCA-positive patients with infective endocarditis presented with pauci-immune necrotizing and crescentic glomerulonephritis. A total of 18.6% of ANCA-positive patients with infective endocarditis were misdiagnosed as ANCA-associated vasculitis.

CONCLUSIONS

ANCA is detected in a substantial proportion of patients with infective endocarditis. The presence of ANCA in infective endocarditis is associated with longer disease duration, more frequent purpura, and kidney involvement. ANCA-positive infective endocarditis may mimic ANCA-associated vasculitis, and the differential diagnosis is challenging. Whether ANCA is pathogenic in infective endocarditis-associated small vessel vasculitis requires further study.

Diagnosing and treating ANCA-associated vasculitis: an updated review for clinical practice

ANCA-associated vasculitides (AAV) are a group of rare, primary, systemic necrotizing small-vessel vasculitides. Granulomatosis with polyangiitis and microscopic polyangiitis account for ∼80–90% of all AAV. Exposure to silica dust, farming and chronic nasal Staphylococcus aureus carriage are associated with increased risk of developing AAV. When a diagnosis of AAV is suspected, as in patients with multisystem organ dysfunction or those with features such as chronic recurrent rhinosinusitis, cavitated lung nodules, palpable purpura or acute kidney injury, then appropriate further investigations are needed, including ANCA testing. In this scenario, a structured clinical assessment should be conducted, evaluating all the organs possibly involved, and tissue biopsy may be necessary for confirmation of the diagnosis. Therapeutic algorithms vary based on the severity of AAV, the clinical diagnosis/ANCA specificity, and the patient’s age, weight, comorbidities and prognosis. Recent data favour rituximab as a preferable option for both induction and maintenance of remission. In addition, regimens with less glucocorticoids are equally effective and safer in inducing remission compared with conventional regimens, and avacopan is an effective glucocorticoid-sparing option. In contrast, there is not compelling evidence to support the routine use of plasma exchange in addition to standard remission-induction therapy in AAV. ANCA and other biomarkers can be helpful in association with clinical assessment to guide diagnosis and treatment decisions. Patients should be frequently evaluated during follow-up for possible disease relapses or treatment-related morbidity, and for monitoring damage accrual, especially metabolic and cardiovascular damage.

Serum ANCA as Disease Biomarkers: Clinical Implications Beyond Vasculitis

Usually associated with autoimmune diseases, anti-neutrophil cytoplasmic antibodies are also detected in other conditions, such as infections, malignancies, and after intake of certain drugs. Even if the mechanisms of production and their pathogenic role have not been fully elucidated yet, ANCA are widely recognized as a clinically alarming finding due to their association with various disorders. While ANCA target several autoantigens, proteinase-3, and myeloperoxidase are the ones proved to be most frequently related to chronic inflammation and tissue damage in murine models. Albeit these autoantibodies could be present as an isolated observation without any implications, ANCA are frequently used in clinical practice to guide the diagnosis in a suspect of small vessel vasculitis. Conditions that should prompt the clinician to test ANCA status range from various forms of lung disease to renal or peripheral nervous system impairment. ANCA positivity in the presence of an autoimmune disease, especially rheumatoid arthritis, or connective tissue diseases, is frequently correlated with more clinical complications and treatment inefficacy, even in the absence of signs of vasculitis. For this reason, it has been postulated that ANCA could represent the final expression of an immune dysregulation rather than a pathogenic event responsible for organs damage. Recently, it has also been proposed that ANCA specificity (PR3 or MPO) could possibly define ANCA-associated vasculitides better than clinical phenotype. This review aims at summarizing the latest advancements in the field of ANCA study and clinical interpretation.

Determination of pediatric reference limits for 10 commonly measured autoantibodies

OBJECTIVES

The objective of this study was to establish pediatric reference limits for autoimmune disease markers in the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) cohort of healthy children and adolescents to support their interpretation and clinical decision making. The CALIPER is a national study of healthy children aiming to close gaps in pediatric laboratory medicine by establishing a robust database of pediatric reference intervals for pediatric disease biomarkers (caliperdatabase.org).

METHODS

Healthy children and adolescents (n=123, aged 1-19) were recruited to CALIPER with informed consent. Serum autoantibody testing conducted on the BIO-FLASH analyzer (Werfen, Barcelona, Spain) included anti-dsDNA IgG, anti-Sm IgG, anti-RNP IgG, anti-SSB/La IgG, anti-Ro60 IgG, anti-Ro52 IgG, anti-cardiolipin IgG, anti-MPO IgG, anti-PR3 IgG, and anti-tTG IgA. Pediatric reference limits representing 95th, 97.5th, and 99th percentiles were calculated using the non-parametric rank method according to Clinical Laboratory Standards Institute C28-A3 guidelines.

RESULTS

The proportion of samples with results above the lower limit of the analytical measuring range were: anti-cardiolipin IgG 90%, anti-dsDNA 22%, anti-Sm 13%, anti-RNP 0.8%, anti-SSB/La 0%, anti-Ro60 0%, anti-Ro52 0%, anti-MPO 25%, anti-PR3 9%, and anti-tTG IgA 28%. Pediatric reference limits and associated 90% confidence intervals were established for all 10 markers. All autoantibodies could be described by one age range except for anti-cardiolipin IgG and anti-MPO. A sex-specific difference was identified for anti-tTG IgA.

CONCLUSIONS

Robust pediatric reference limits for 10 commonly clinically utilized autoimmune markers established herein will allow for improved laboratory assessment and clinical decision making in pediatric patients using the BIO-FLASH assay platform worldwide.

Autoantibodies in Wilson disease: Impact on clinical course

Symptoms of Wilson disease (WD) vary and additional factors such as autoimmunity may play an important role in WD pathogenesis. The presence of antinuclear antibodies (ANA), anti‐neutrophil cytoplasmic antibodies, neuronal surface antibodies, and onconeural antibodies in WD was investigated using standardized indirect immunofluorescence assays and Western Blot analysis. The presence of all studied autoantibodies was higher in WD patients in comparison to healthy subjects, but there was no statistically significant difference in autoantibodies frequency according to disease manifestation. D‐penicillamine treatment was associated with a higher presence of ANA than zinc sulfate but without an increase in autoimmune diseases rate.

Spectrum of Large- and Medium-Vessel Vasculitis in Adults: Neoplastic, Infectious, Drug-Induced, Autoinflammatory, and Primary Immunodeficiency Diseases

Purpose of Review

To provide a comprehensive review of drugs and neoplastic, infectious, autoinflammatory, and immunodeficiency diseases causing medium- to large-vessel vasculitis in adults with emphasis on information essential for the initial diagnostic process.

Recent Findings

Entities with medium- to large-vessel vasculitis as clinical manifestations have been described recently (e.g., adenosine deaminase-2 deficiency, VEXAS-Syndrome), and vasculitis in established autoinflammatory or immunodeficiency diseases is increasingly being identified.

Summary

In the diagnostic process of medium- to large-vessel vasculitis in adults, a large variety of rare diseases should be included in the differential diagnosis, especially if diagnosis is made without histologic confirmation and in younger patients. Although these disorders should be considered, they will undoubtedly remain rare in daily practice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11926-022-01083-5.

Modified Body Mass Index at Diagnosis is a Useful Predictor of Mortality in Patients With Antineutrophil Cytoplasmic Antibody-associated Vasculitis

Objective

We investigated whether modified body mass index (mBMI) at diagnosis could predict all-cause mortality during follow-up in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

Methods

The medical records of 203 AAV patients with BMI ≥18.5 kg/m2 were reviewed. mBMI was calculated using an equation mBMI=BMI (kg/m2)×serum albumin (g/L). All-cause mortality was considered as a poor outcome, and the follow-up duration based on all-cause mortality was defined as the period from AAV diagnosis to death for deceased patients, and the period from AAV diagnosis to the last visit for surviving patients.

Results

The median age was 59.0 years (35.5% were male). The median BMI and mBMI were 22.8 kg/m2 and 813.2 kg · g/m2 · L. Twenty-five patients (12.3%) died. mBMI was well correlated with age, BVAS, FFS, erythrocyte sedimentation rate and C-reactive protein at diagnosis. Deceased patients exhibited significantly lower mBMI at diagnosis compared to surviving patients. AAV patients mBMI ≤570.1 kg · g/m2 · L showed a significantly higher frequency of all-cause mortality (38.5% vs. 8.5%), and furthermore, exhibited a significantly higher risk for all-cause mortality than those with mBMI >570.1 kg · g/m2 · L (RR 6.750). mBMI ≤570.1 kg · g/m2 · L showed a significantly lower cumulative patients' survival rate than those with mBMI >570.1 kg · g/m2 · L. In the multivariable Cox hazards model analysis, either serum albumin or mBMI was significantly associated with all-cause mortality in AAV patients.

Conclusion

In conclusion, mBMI ≤570.1 kg · g/m2 · L at diagnosis may be a useful predictor of all-cause mortality during follow-up additionally to serum albumin in AAV patients.

Autoimmune liver diseases in systemic rheumatic diseases

Systemic rheumatic diseases (SRDs) are chronic, inflammatory, autoimmune disorders with the presence of autoantibodies that may affect any organ or system. Liver dysfunction in SRDs can be associated with prescribed drugs, viral hepatitis, alternative hepatic comorbidities and coexisting autoimmune liver diseases (AILDs), requiring an exclusion of secondary conditions before considering liver involvement. The patterns of overlap diseases depend predominantly on genetic determinants with common susceptible loci widely distributing in both disorders. In AILDs, it is important to identify the overlapping SRDs at an early stage since such a coexistence may influence the disease course and prognosis. Commonly co-occurring SRDs in AILDs are Sjögren syndrome (SS), rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) in autoimmune hepatitis (AIH), and SS, RA or systemic sclerosis in primary biliary cholangitis. Owing to different disease complications and therapies, it is imperative to differentiate between SLE liver involvement and SLE-AIH overlap disease. Therapeutic options can be personalized to control coexisting conditions of liver autoimmunity and rheumatic manifestations in AILD-SRD overlap diseases. The collaboration between hepatologists and rheumatologists can lead to significant advances in managing such a complex scenario. In this review, we provide a comprehensive overview on coexisting AILDs in different SRDs and the therapeutic approach in managing these overlap diseases.

A case of smoldering antineutrophil cytoplasmic antibody-associated vasculitis development during the course of primary Sjögren's syndrome

Various forms of glomerular lesions have been described in primary Sjögren's syndrome (pSjS); however, myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is rarely reported, and the disease onset and clinical course of ANCA-associated vasculitis (AAV) complicated by pSjS are not well understood. A 51-year-old woman was referred to our hospital because of mild proteinuria and microscopic hematuria. She fulfilled the classification criteria for pSjS. We performed a kidney biopsy; however, it revealed no characteristic findings for pSjS, vasculitis, or other autoimmune diseases, including systemic lupus erythematosus. After 9 months, urinalysis abnormalities worsened and renal function was slowly declining, and ANCA was found to be positive. A second kidney biopsy was performed, revealing MPO-ANCA-associated pauci-immune segmental necrotizing glomerulonephritis with crescent formation. Even though immunofluorescence microscopy did not reveal any positive findings, additional electron microscopy demonstrated the presence of mesangial electron-dense deposits in both kidney biopsies. Based on kidney biopsy results and sequential serum ANCA measurements, we considered that smoldering ANCA-associated vasculitis had developed in this patient as this can develop during the clinical course of pSjS. She responded well to steroid therapy. Serum measurement, especially perinuclear, ANCA levels can be useful in patients with pSjS to detect the onset of ANCA-associated vasculitis, even in the absence of acute renal deterioration or severe urinary abnormalities.

Performance of MPO-ANCA and PR3-ANCA immunoassays for the stratification of specific ANCA-associated vasculitis: A systematic review and meta-analysis

OBJECTIVE

To determine the impact of myeloperoxidase (MPO) and proteinase 3 (PR3) antigen-specific immunoassays in the stratification of patients at-risk for anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) at diagnosis.

METHODS

A Medline search was conducted to identify diagnostic accuracy studies using PR3-ANCA or MPO-ANCA for the evaluation of granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Studies estimates were pooled using the bivariate method.

RESULTS

Diagnostic accuracy varied by analyte and AAV subtype. PR3-ANCA had greater sensitivity than MPO-ANCA for GPA (74% vs 11%, p < 0.001) and MPO-ANCA greater sensitivity for MPA (73% vs 7%, p < 0.001). Specificities of both MPO-ANCA and PR3-ANCA were consistently high (mean 97%, range: 93-99%) for both AAV subtypes. There was insufficient data to perform meta-analysis for the diagnostic accuracy of EPGA.

CONCLUSION

These results validate the use of high quality MPO-ANCA and PR3-ANCA immunoassays to screen patients at-risk for AAV as well as to categorize disease as GPA or MPA subtype. However, caution must be exercised in doing so, since some assays may not have optimal performance. Each laboratory should validate appropriate algorithms based on the tests used and testing population.

Anti-Proteinase 3 Antibodies as a Biomarker for Ulcerative Colitis and Primary Sclerosing Cholangitis in Children

OBJECTIVES

Anti-neutrophil cytoplasmic antibody (ANCA) directed against proteinase 3 (PR3) is a marker for granulomatosis with polyangiitis, but is also found in patients with inflammatory bowel disease (IBD), mainly ulcerative colitis (UC). The aim of our study was to investigate ANCA and PR3-ANCA in paediatric IBD.

METHODS

We tested 326 paediatric IBD patients and 164 controls for anti-Saccharomyces cerevisiae antibodies (ASCA), ANCA (indirect immunofluorescence, IIF) and PR3-ANCA (chemiluminescence immunoassay). We applied the Paris classification for paediatric IBD and documented liver manifestations such as primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH).

RESULTS

We found PR3-ANCA in 49/121 (40%) of UC, 20/187 (11%) of Crohn disease (CD) and 2/18 (11%) of IBD-unclassified (IBD-U) patients but in none of the controls. 54% UC and 12% CD patients were positive for ANCA (IIF). PR3-ANCA positive UC patients were characterised by more extensive disease (P = .070). Fourteen of 21 (67%) of UC patients with backwash ileitis were anti-PR3 ANCA-positive (P = .011). We diagnosed PSC or PSC/AIH in 19 UC and 3 IBD-U patients. Fifteen of 22 (68%) patients with PSC or PSC/AIH were anti-PR3-ANCA positive in contrast to 36 of 117 (32%) patients without PSC (P = .001). PR3-ANCA positive patients showed higher levels of gamma-glutamyl transferase, alanine transaminase and aspartate transferase (P < 0.001, 0.001, 0.006, respectively). Forty-seven percent of CD and 6% of UC patients were ASCA-IgA positive. PR3-ANCA-positive and -negative patients showed no significant differences concerning age at diagnosis, disease activity, need for drugs, and number of hospitalisations.

CONCLUSIONS

Our study provides data for PR3-ANCA as a potential serological marker for paediatric UC and PSC.

ANCA Associated Vasculitis Subtypes: Recent Insights and Future Perspectives

The ANCA associated vasculitides (AAVs) affect a range of internal organs including ear nose and throat, respiratory tract, kidneys, skin and nervous system. They include granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA) and microscopic polyangiitis (MPA). The AAVs are treated with high dose glucocorticoids, immunosuppressants, and targeted biological medications. Since the 1990s classification criteria for the AAVs have been based on clinical features, laboratory tests and basic imaging; an initiative to update the classification criteria incorporating newer tests, for example, anti-neutrophil cytoplasmic antibodies (ANCA) and novel imaging techniques will be published this year. There is also evidence for classification of patients based on ANCA subtype; those with anti-proteinase 3 antibodies (PR3) or anti-myeloperoxidase antibodies (MPO) have differences in response to treatment and clinical outcomes. An update is described within this review. The pathogenesis of AAV involves necrotizing inflammation of small to medium blood vessels involving multiple immunological pathways. We present an update on emerging evidence related to auto-antibodies, complement and lymphocyte pathways. This review describes emerging treatment regimens, including evidence for plasma exchange in severe disease and the inhibitor of the complement C5a receptor (C5aR) inhibitor, Avacopan. Lastly, patient reported outcomes are key secondary outcomes in randomised controlled trials and increasingly clinical practice, we report development in disease specific and glucocorticoid-specific PROs.

Aryl Hydrocarbon Receptor Mechanisms Affecting Chronic Kidney Disease

The aryl hydrocarbon receptor (AHR) is a basic helix-loop-helix transcription factor that binds diverse endogenous and xenobiotic ligands, which regulate AHR stability, transcriptional activity, and cell signaling. AHR activity is strongly implicated throughout the course of chronic kidney disease (CKD). Many diverse organic molecules bind and activate AHR and these ligands are reported to either promote glomerular and tubular damage or protect against kidney injury. AHR crosstalk with estrogen, peroxisome proliferator-activated receptor-γ, and NF-κB pathways may contribute to the diversity of AHR responses during the various forms and stages of CKD. The roles of AHR in kidney fibrosis, metabolism and the renin angiotensin system are described to offer insight into CKD pathogenesis and therapies.

[Eosinophilic granulomatosis with polyangiitis : Update on classification and management]

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare chronic inflammatory systemic disease that occurs in patients with bronchial asthma and is associated with significant blood and tissue eosinophilia. Another characteristic is vasculitis of small and/or medium-sized vessels, which may be absent in prodromal stages of the disease and is therefore no longer an obligatory part of the disease definition. Antineutrophil cytoplasmic antibodies (ANCA) can be detected in approximately one third of patients. The ANCA-positive and ANCA-negative EGPA are genetically distinct diseases with common clinical manifestations, which, however, occur with different frequencies. Cardiac involvement is associated with a poor prognosis. Permanent organ damage often occurs as a result of the underlying disease or treatment, especially with glucocorticoids (GC). The standard treatment of EGPA consists of GC in combination with cyclophosphamide for severe organ involvement or medium potency immunosuppressants for more prognostically favorable manifestations. Biologics are increasingly being used in the treatment of EGPA. The interleukin (IL) 5 antagonist mepolizumab reduces the risk of relapses and decreases the demand for GC in patients with relapsing EGPA without severe organ involvement. In analogy to the approach to other ANCA-associated vasculitides, the use of rituximab in ANCA-positive EGPA patients with severe vasculitis recurrence is a possible option, even though formal evidence for such an approach is currently low and formal approval is lacking.

The Role of Autoantibodies in the Diagnosis of Autoimmune Liver Disease: Lessons Learned from Clinical Practice

BACKGROUND

Primary biliary cholangitis (PBC), autoimmune hepatitis (AIH) and primary sclerosing cholangitis (PSC) are autoimmune liver diseases associated with distinct autoantibodies. Diagnosis is based upon clinical, serological, and histopathology findings. The role of autoantibodies in the diagnosis of these autoimmune liver diseases, with the focus on PBC and AIH, will be discussed.

CONTENT

When AIH or PBC is suspected, testing for multiple autoantibodies can be requested. In this mini-review, the different ways in which autoantibodies can be tested (indirect immunofluorescence and antigen-specific tests) in the context of PBC and AIH are discussed, as well as the pitfalls in interpreting the test results.

SUMMARY

For appropriate interpretation of test results, an important prerequisite is that the doctor knows which test is used in the laboratory of choice and that the laboratory specialist is aware of what the doctor wants to test for. Good communication between clinician and laboratory specialist can, therefore, aid in the diagnosis of autoimmune liver diseases.

Clinical, Methodological, and Practical Considerations for Algorithmic Testing in Autoimmune Serology

BACKGROUND

Autoimmune serology tests are central to the classification, screening, diagnosis, and monitoring of a variety of autoimmune disorders. To improve the appropriateness of serologic evaluation and support laboratory resource utilization, reflex testing approaches have been proposed and implemented across clinical laboratories. Reflex testing involves a staged approach where an initial test result triggers subsequent tests based on prespecified rules.

CONTENT

Various reflex testing approaches in the context of antinuclear antibody-associated rheumatic disease, antineutrophil cytoplasmic autoantibody-associated vasculitis, celiac disease, and myasthenia gravis are reviewed here. Clinical, analytical, and practical considerations of reflex testing implementation are addressed as well as associated limitations and challenges.

SUMMARY

Serology reflex testing algorithms for the evaluation of autoimmune diseases can support clinical diagnosis and laboratory resource use but may be challenging to implement and are often applied variably across institutions. Assessments of evidence-driven guidelines, clinical impact, and impact on laboratory workflow are essential to this task.

Association Between Idiopathic Cutaneous Leukocytoclastic Angiitis and ANCA-negative Microscopic Polyangiitis

Objective

This study retrospectively reviewed the process of classifying antineutrophil cytoplasmic antibody (ANCA)-negative granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) in a cohort of patients with ANCA-associated vasculitis (AAV), and investigated the association between recurrent idiopathic cutaneous leukocytoclastic angiitis and ANCA-negative MPA.

Methods

The medical records of 242 patients with AAV were retrospectively reviewed Of 49 patients with ANCA-negative AAV, 24 patients with ANCA-negative eosinophilic GPA (EGPA) were excluded, because ANCA positivity or negativity is not critical in classifying EGPA Ultimately, 25 patients with ANCA-negative GPA and MPA were analysed in this study The classification of GPA and MPA were based on the 2007 European Medicines Agency algorithm for AAV.

Results

The median age of patients with ANCA-negative GPA and MPA was 540 years and 24% were male Of the 25 patients without ANCA, 8 patients were classified as GPA and 17 as MPA Eight patients with ANCA-negative GPA were easily confirmed as definitive GPA Fourteen of the 17 patients ANCA-negative MPA were classified as MPA based on histological features suggestive of AAV without granuloma formation and the absence of surrogate markers for GPA Meanwhile, three of the patients that were ANCA-negative exhibited only recurrent idiopathic cutaneous leukocytoclastic angiitis without other major organs affected and thus were classified as possible MPA Within one year, they were classified as definitive MPA based on ANCA positivity and/or renal histology.

Conclusion

Recurrent idiopathic cutaneous leukocytoclastic angiitis may be associated with ANCA-negative MPA in patients who exhibit cutaneous necrotising vasculitis.

Disease criteria of systemic lupus erythematosus (SLE); the potential role of non-criteria autoantibodies

Patients with SLE show a broad spectrum of more than 200 autoantibodies. They can be pathogenic, predictive, prognostic or even an epiphenomenon. Here, we discuss different autoantibodies that have not been included in EULAR/ACR 2019 classification criteria. Most of them have been addressed to monitor and detect disease activity and not specifically as classification criteria. Indeed, markers to assess disease activity fluctuate as compared with classification criteria and their validation is different. The development of new methods will probably bring new clinical associations and be evaluated as potential classification criteria.

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Most of the autoantibodies described in SLE are of utility in monitoring disease activity.

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The validation of activity biomarkers is different from classification criteria biomarkers.

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The new methods coming into the clinical routine will bring new associations and potentially classification criteria.