Classification criteria for ANCA-associated vasculitis: one size does not fit all!

Comparison of EULAR/PRINTO/PReS Ankara 2008 and 2022 ACR/EULAR classification criteria for granulomatosis with polyangiitis in children

OBJECTIVE

Granulomatosis with polyangiitis (GPA) is an ANCA-associated vasculitis. The 2022 ACR/EULAR-endorsed classification criteria for GPA was derived using data only from adult patients. We aimed to assess the performance of the ACR/EULAR classification criteria for GPA in paediatric patients and compare it with the EULAR/Pediatric Rheumatology International Trials Organization (PRINTO)/Pediatric Rheumatology European Society (PReS)-endorsed Ankara 2008 criteria for GPA.

METHODS

Retrospective data of paediatric patients with GPA in 20 centres from 9 countries were evaluated. The diagnosis of GPA was made according to the expert opinion. The sensitivity, specificity, positive predictive value, and negative predictive value of the criteria sets were evaluated.

RESULTS

The study included 77 patients with GPA and 108 controls [IgA vasculitis (n = 44), Takayasu's arteritis (n = 20), microscopic polyangiitis (n = 16), polyarteritis nodosa (n = 14), Behçet's disease (n = 12), eosinophilic granulomatosis with polyangiitis (n = 1) and Cogan's syndrome (n = 1)] with a median age of 17.8 and 15.2 years, respectively. Among patients with GPA, constitutional symptoms (85.7%) and ENT involvement (79.2%) were the most common presentations. In the GPA group, 73 patients fulfilled the Ankara 2008 criteria and 69 the ACR/EULAR classification criteria. Sensitivities of the Ankara 2008 criteria and the ACR/EULAR classification criteria were 94.8% and 89.6%, while specificities were 95.3% and 96.3%, respectively. No significant difference was found between sensitivities and specificities of both classification criteria (P = 0.229 and P = 0.733, respectively).

CONCLUSION

In children, both the ACR/EULAR and EULAR/PRINTO/PReS Ankara 2008 classification criteria for GPA perform well and similarly.

Classification Criteria for ANCA Associated Vasculitis - Ready for Prime Time?

PURPOSE OF REVIEW

This review aims to summarize the evolution and recent developments in the classification of ANCA associated vasculitis (AAV) and to summarize evaluations of the 2022 ACR/EULAR classification criteria of AAV in several cohorts.

RECENT FINDINGS

The classification of AAV has been a field of controversy for some time. The parallel existence of classification criteria and disease definitions produced some overlap in classification, leading to challenges when comparing different cohorts. The 2022 ACR/EULAR classification criteria derived from the largest study ever conducted in vasculitis account for significant changes in vasculitis classification with the integration of ANCA and modern imaging. These criteria show good performance compared to previous ones but also raise questions as ANCA serotypes have substantial impact on classification. In addition, there are some discrepancies with earlier agreed histopathological features of AAV disease phenotypes. During the last 35 years, several sets of classification criteria have evolved to facilitate epidemiologic studies and clinical trials in AAV. While some of these criteria have been in use for many years, they were criticized due to either not using ANCA or not integrating surrogate markers for vasculitis but also due to overlapping when used in parallel. The long-awaited new ACR/EULAR criteria for AAV were published in 2022 and are the result of a large international study, introducing for the first time ANCA and modern imaging in the classification of AAV. Though the criteria show good performance, they bring several other challenges with practical application.

Treatment strategies for ANCA-associated vasculitides: from standard protocols to future horizons

INTRODUCTION

ANCA-associated vasculitides (AAV), classified into granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis represent a group of disorders characterized by necrotizing vasculitis of small vessels, endothelial injury and tissue damage. The outcomes and prognosis of AAV have undergone significant changes with the introduction of glucocorticoids (GCs) and other immunosuppressants (cyclophosphamide, azathioprine, methotrexate, and mycophenolate mofetil). The enhanced understanding of pathogenesis has subsequently led to the incorporation into clinical practice of drugs targeting specific therapeutic targets.

AREAS COVERED

After an extensive literature search of Pubmed, Medline, Embase of the most recent evidence, we provide an overview of available treatments, highlighting how newer drugs have integrated into standard protocols. Our review also explores potential new therapeutic targets, including B cell depletion and inhibition, T cell inhibition, complement inhibition, and IL-5 and IgE inhibition.

EXPERT OPINION

There is hope that the new treatment targets currently under study in AAV may enable a faster and more lasting clinical response, ensuring the reduction of possible side effects from therapies. Moreover, numerous aspects necessitate further exploration in the future, such as tailoring of GCs, integration of GCs-sparing agents, efficacy of combination therapy, optimal maintenance therapy, to reduce organ-damage and improve quality of life.

[Management of ANCA-associated vasculitides]

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune-mediated inflammation of small and medium-sized vessels that can affect virtually any organ system and bears the risk of irreversible organ damage. Without treatment the mortality rates are high, which necessitates rapid diagnosis and initiation of treatment. Histological confirmation, which is not feasible in all cases, should be strived for, especially to delineate differential diagnoses and vasculitis mimics. The new American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) classification criteria are primarily designed for study purposes and show limitations in the routine application. Globally, the recently updated EULAR recommendations represent the most up to date management guidelines. Therapeutically, rituximab and cyclophosphamide in combination with glucocorticoids remain the pillars of treatment in remission induction for severe organ-threatening and life-threatening diseases. For the first time, mepolizumab and avacopan represent approved treatment options for specific entities that make a significant contribution to steroid reduction. New attention has been paid to patient-reported outcomes, for which a disease-specific outcome questionnaire is now available.

Glomerular Diseases Across Lifespan: Key Differences in Diagnostic and Therapeutic Approaches

Glomerular diseases are common causes of chronic kidney disease in childhood, adolescence, and adulthood. The epidemiology of glomerular diseases differs between different age groups, with minimal change disease being the leading cause of nephrotic syndrome in childhood, while membranous nephropathy and focal segmental glomerulosclerosis are more common in adulthood. IgA vasculitis is also more common in childhood. Moreover, there is a difference in disease severity with more children presenting with a relapsing form of nephrotic syndrome and a more acute presentation of antineutrophil cytoplasmic antibody-associated vasculitis and concomitant glomerulonephritis, as highlighted by the higher percentage of cellular crescents on kidney biopsy specimens in comparison with older patients. There is also a female preponderance in antineutrophil cytoplasmic antibody-associated vasculitis and more children present with tracheobroncholaryngeal disease. This article aims to summarize differences in the presentation of different glomerular diseases that are encountered commonly by pediatric and adult nephrologists and potential differences in the management.