Granuloma in ANCA-associated vasculitides: another reason to distinguish between syndromes?

Nailfold Capillaroscopy Analysis Can Add a New Perspective to Biomarker Research in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

BACKGROUND

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) includes granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA), all of which are characterised by inflammation of small-medium-sized vessels. Progressive understanding of these diseases has allowed researchers and clinicians to start discussing nailfold video capillaroscopy (NVC) as a future tool for many applications in daily practice. Today, NVC plays a well-established and validated role in differentiating primary from secondary Raynaud's phenomenon correlated with scleroderma. Nevertheless, there has not been sufficient attention paid to its real potential in the ANCA-associated vasculitis. In fact, the role of NVC in vasculitis has never been defined and studied in a multicentre and multinational study. In this review, we carried out a literature analysis to identify and synthesise the possible role of capillaroscopy for patients with ANCA-associated vasculitis.

METHODS

Critical research was performed in the electronic archive (PUBMED, UpToDate, Google Scholar, ResearchGate), supplemented with manual research. We searched in these databases for articles published until November 2023. The following search words were searched in the databases in all possible combinations: capillaroscopy, video capillaroscopy, nailfold-video capillaroscopy, ANCA-associated vasculitis, vasculitis, granulomatosis with polyangiitis, EGPA, and microscopic polyangiitis.

RESULTS

The search identified 102 unique search results. After the evaluation, eight articles were selected for further study. The literature reported that capillaroscopy investigations documented non-specific abnormalities in 70-80% of AAV patients. Several patients showed neoangiogenesis, capillary loss, microhaemorrhages, and bushy and enlarged capillaries as the most frequent findings. Furthermore, the difference between active phase and non-active phase in AAV patients was clearly discernible. The non-active phase showed similar rates of capillaroscopy alterations compared to the healthy subjects, but the active phase had higher rates in almost all common abnormalities instead.

CONCLUSIONS

Microvascular nailfold changes, observed in patients affected by vasculitis, may correlate with the outcome of these patients. However, these non-specific abnormalities may help in the diagnosis of vasculitis. As such, new analysis analyses are necessary to confirm our results.

MPO-ANCA-positive granulomatosis with polyangiitis and concurrent IgG4-related disease with periaortitis and tubulointerstitial nephritis: A case report of a new overlap syndrome?

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition that was first recognized as a unique disease entity in the early 2000s. Its diagnosis is based on specific pathologic, serologic, and clinical features, and the exclusion of several differential diagnoses, such antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). However, emerging evidence suggests that these 2 conditions may overlap in some cases. Here, we report a new case of overlapping IgG4-RD and AAV. The patient was diagnosed with IgG4-RD owing to the presence of periaortitis and IgG4 positive tubulointerstitial nephritis. Myeloperoxidase (MPO)-ANCA positivity, chronic paranasal sinusitis, and glomerulonephritis with granuloma led to a concurrent diagnosis of MPO-ANCA-positive granulomatosis with polyangiitis. Our case supports the hypothesis that diagnoses of IgG4-RD and AAV are not mutually exclusive but can overlap. It can be assumed that an overlap with IgG4-RD typically affects the granulomatous form of AAV, suggesting a common pathophysiological pathway for these 2 conditions.

Combination Treatment of Locoregionally Aggressive Granulomatosis with Polyangiitis and Cranial Base Infiltration

OBJECTIVES

To present a personalized approach in three cases of treatment-resistant, locoregionally aggressive forms of cANCA-positive granulomatosis with polyangiitis (GPA) and skull base involvement.

METHODS

Three patients with GPA and skull base involvement were described alongside a critical review of the current literature.

RESULTS

All presented patients suffered from GPA with an inflammatory tumor at the skull base, alongside cerebellopontine angle involvement, cranial nerve palsies, cerebellar disorders, concomitant hearing loss, and severe otalgia. Symptoms were associated with progressive granulomatous destruction of the temporal bone, laryngopharynx, and central nervous system infiltration. Treatment with cyclophosphamide and high doses of glucocorticoid steroids were ineffective but subsequent therapy with rituximab was successful in the presented cases. The literature review showed that the course of the disease with skull base involvement is associated with poorer clinical and radiological responses to standard pharmacotherapies.

CONCLUSION

Granulomatous inflammation localized in the skull base is associated with a more aggressive disease progression and is less likely to respond to pharmacotherapy. Standard induction therapy with cyclophosphamide and glucocorticoid steroids may be ineffective. A better response may be achieved by using rituximab and concomitant local treatment with glucocorticoid steroid injections.

Current concepts in granulomatosis poly angiitis and the eye

Purpose of review

Granulomatosis with polyangiitis (GPA), a multisystem disease with diverse systemic and protean ocular manifestations. Its pathophysiology, spectrum of the ocular manifestations, changing paradigms in the diagnosis of the disease, recent updates in the treatment patterns are clinically relevant to the treating clinician. They are described in this review.

Recent findings

Summary

The changing trends in the diagnosis, treatment can be adapted to real time clinical practice to provide the best quality of life to patients with GPA.

Environmental factors influencing the risk of ANCA-associated vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of diseases characterized by inflammation and destruction of small and medium-sized blood vessels. Clinical disease phenotypes include microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA). The incidence of AAV has been on the rise in recent years with advances in ANCA testing. The etiology and pathogenesis of AAV are multifactorial and influenced by both genetic and environmental factors, as well as innate and adaptive immune system responses. Multiple case reports have shown that sustained exposure to silica in an occupational environment resulted in a significantly increased risk of ANCA positivity. A meta-analysis involving six case-control studies showed that silica exposure was positively associated with AAV incidence. Additionally, exposure to air pollutants, such as carbon monoxide (CO), is a risk factor for AAV. AAV has seasonal trends. Studies have shown that various environmental factors stimulate the body to activate neutrophils and expose their own antigens, resulting in the release of proteases and neutrophil extracellular traps, which damage vascular endothelial cells. Additionally, the activation of complement replacement pathways may exacerbate vascular inflammation. However, the role of environmental factors in the etiology of AAV remains unclear and has received little attention. In this review, we summarized the recent literature on the study of environmental factors, such as seasons, air pollution, latitude, silica, and microbial infection, in AAV with the aim of exploring the relationship between environmental factors and AAV and possible mechanisms of action to provide a scientific basis for the prevention and treatment of AAV.

Current clinical and therapeutic approach to tumour-like mass lesions in granulomatosis with polyangiitis

Granulomatosis with polyangiitis (GPA) is a systemic autoimmune disorder classified among the anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and characterized by a triad of upper and lower respiratory tract disease, systemic vasculitis involving small-to-medium vessels and renal manifestations. Mass lesions, also described as inflammatory lesions, pseudotumor or tumour-like masses, are uncommon manifestations of GPA and are often called granuloma since histology examination shows granulomatous inflammation and rarely vasculitis. Masses could represent a localized manifestation of GPA or develop as part of a systemic disease. Unusual clinical presentation together with nonspecific radiological and histological features may delay the correct diagnosis leading to disease progression and organ damage. Diagnosis of GPA in such cases may be challenging and malignancy or infections must be considered as alternative diagnostic options. Here we reviewed all the different sites where mass lesions were reported in GPA, focusing on atypical localization, and summarized current therapeutic options and their different outcomes. We retrieved and discussed the cases reported since 2010, bearing in mind the advances in the therapeutic management of AAV patients in the last decade, namely biological therapy such as rituximab. Despite treatment regimens with glucocorticoids and immunosuppressive agents, mass lesions have a refractory course in a high proportion of patients. Invasive surgical procedures may be considered only when drug therapy fails.

Granulomatous Inflammation in ANCA-Associated Vasculitis

ANCA-associated vasculitis (AAV) comprises granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). While systemic vasculitis is a hallmark of all AAV, GPA is characterized by extravascular granulomatous inflammation, preferentially affecting the respiratory tract. The mechanisms underlying the emergence of neutrophilic microabscesses; the appearance of multinucleated giant cells; and subsequent granuloma formation, finally leading to scarred or destroyed tissue in GPA, are still incompletely understood. This review summarizes findings describing the presence and function of molecules and cells contributing to granulomatous inflammation in the respiratory tract and to renal inflammation observed in GPA. In addition, factors affecting or promoting the development of granulomatous inflammation such as microbial infections, the nasal microbiome, and the release of damage-associated molecular patterns (DAMP) are discussed. Further, on the basis of numerous results, we argue that, in situ, various ways of exposure linked with a high number of infiltrating proteinase 3 (PR3)- and myeloperoxidase (MPO)-expressing leukocytes lower the threshold for the presentation of an altered PR3 and possibly also of MPO, provoking the local development of ANCA autoimmune responses, aided by the formation of ectopic lymphoid structures. Although extravascular granulomatous inflammation is unique to GPA, similar molecular and cellular patterns can be found in both the respiratory tract and kidney tissue of GPA and MPA patients; for example, the antimicrobial peptide LL37, CD163⁺ macrophages, or regulatory T cells. Therefore, we postulate that granulomatous inflammation in GPA or PR3-AAV is intertwined with autoimmune and destructive mechanisms also seen at other sites.

Recent advances in understanding of the pathogenesis of ANCA-associated vasculitis

Anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV) are rare systemic autoimmune diseases characterised by inflammation of small blood vessels. Recent developments have been made in our understanding of the pathogenesis of these diseases, including the pathogenic role of ANCA, neutrophils and monocytes as mediators of injury, dysregulation of the complement system, and the role of T and B cells. Current treatment strategies for AAV are based on broad immunosuppression, which may have significant side effects. Advances in understanding of the pathogenesis of disease have led to the identification of new therapeutic targets which may lead to treatment protocols with less-toxic side effects. The aim of this review is to summarise current information and recent advances in understanding of the pathogenesis of AAV.

Intractable otitis media as a diagnostic clue to antineutrophil cytoplasmic antibody-associated vasculitis

Antineutrophil cytoplasmic antibody‐associated vasculitis (AAV) presents a variety of manifestations. Two patients with a history of intractable otitis media were diagnosed as having AAV. One was an 87‐year‐old woman who presented with cough, anorexia, and fever with a one‐year and four‐month history of otitis media, and the other was a 65‐year‐old woman with arthritis that appeared after the diagnosis of otitis media. The history of otitis media was a diagnostic clue to AAV in both patients. Diagnosis at the early localized stage is crucial to prevent irreversible status of AAV. Primary care physicians should be aware of the otological manifestation of AAV.

Classification, diagnosis and treatment of ANCA-associated vasculitis

Diagnosis of anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis is usually not difficult in patient with systemic disease, including lung and kidneys involvement, and laboratory signs of inflammation. The presence of ANCA and the results of histological investigation confirm diagnosis of ANCA-associated vasculitis. Cyclophosphamide/azathioprine in combination with high dose steroids are used to induce and maintain remission of systemic vasculitis. The clinical trials also showed efficacy of rituximab that induces depletion of B-cells. Our understanding and management of ANCA-associated vasculitis improved significantly over the last decades but there is still a lot of debate over its classification, diagnostic criteria, assessment of activity and optimum treatment.

Pathogenesis of anti-neutrophil cytoplasmic antibody-associated vasculitis: challenges and solutions 2014

Anti-neutrophil cytoplasmic autoantibodies (ANCA) with specificity for proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA) are a defining feature of ANCA-associated vasculitides (AAV). They play a pivotal role in disease pathophysiology and have strongly improved early diagnosis and treatment of these infrequent, but potentially fatal diseases. Neutrophils and their products are major players in initiating the autoimmune response and tissue destruction in vasculitic as well as granulomatous inflammation. This review highlights recent findings on old and novel players (ANCA, neutrophils, neutrophil extracellular traps, fibroblasts, immune cells and complement) and puts them into context with the current understanding of disease mechanisms in AAV.

T cell-macrophage interactions and granuloma formation in vasculitis

Granuloma formation, bringing into close proximity highly activated macrophages and T cells, is a typical event in inflammatory blood vessel diseases, and is noted in the name of several of the vasculitides. It is not known whether specific properties of the microenvironment in the blood vessel wall or the immediate surroundings of blood vessels contribute to granuloma formation and, in some cases, generation of multinucleated giant cells. Granulomas provide a specialized niche to optimize macrophage-T cell interactions, strongly activating both cell types. This is mirrored by the intensity of the systemic inflammation encountered in patients with vasculitis, often presenting with malaise, weight loss, fever, and strongly upregulated acute phase responses. As a sophisticated and highly organized structure, granulomas can serve as an ideal site to induce differentiation and maturation of T cells. The granulomas possibly seed aberrant Th1 and Th17 cells into the circulation, which are known to be the main pathogenic cells in vasculitis. Through the induction of memory T cells, aberrant innate immune responses can imprint the host immune system for decades to come and promote chronicity of the disease process. Improved understanding of T cell-macrophage interactions will redefine pathogenic models in the vasculitides and provide new avenues for immunomodulatory therapy.

Critical appraisal of classification criteria for vasculitides

The vasculitides are a group of protean diseases, some of which are caused by conditions including infections, other autoimmune diseases, or neoplasias. They are a challenge to the clinician, in terms of both diagnosis and therapy. No diagnostic criteria exist, although a multinational effort to develop them is in progress. However, many classification criteria have been proposed, and these have served as diagnostic surrogates and have made it possible to discriminate between many, although not all, of the vasculitides, mainly for epidemiological and therapeutic trial design purposes. In this review we recognise the difficulties of defining such criteria, but at the same time attempt to provide a critical overview of efforts to do so. The increasing knowledge regarding many of these diseases makes us confident that the time will come when their aetiology, or at least their main pathogenic features, is known, rendering proposed classification criteria obsolete.