Clinical and immunological features of drug-induced and infection-induced proteinase 3-antineutrophil cytoplasmic antibodies and myeloperoxidase-antineutrophil cytoplasmic antibodies and vasculitis

Cocaine- and Levamisole-Induced Vasculitis: Defining the Spectrum of Autoimmune Manifestations

Drug-induced or associated vasculitis is a prevalent form of vasculitis that resembles primary idiopathic antineutrophil cytoplasmic autoantibody (ANCA) vasculitis (AAV). Cocaine is a diffuse psychostimulant drug and levamisole is a synthetic compound used to cut cocaine. Their abuse may result in a spectrum of autoimmune manifestations which could be categorized into three overlapping clinical pictures: cocaine-induced midline destructive lesion (CIMDL), levamisole-adulterated cocaine (LAC) vasculopathy/vasculitis, and cocaine-induced vasculitis (CIV). The mechanisms by which cocaine use leads to disorders resembling AAV are not well understood. Cocaine can cause autoimmune manifestations ranging from localized nasal lesions to systemic diseases, with neutrophils playing a key role through NETosis and ANCA development, which exacerbates immune responses and tissue damage. Diagnosing and treating these conditions becomes challenging when cocaine and levamisole abuse is not suspected, due to the differences and overlaps in clinical, diagnostic, therapeutic, and prognostic aspects compared to primary idiopathic vasculitides.

The role of ANCA in the management of cocaine-induced midline destructive lesions or ENT pseudo-granulomatosis with polyangiitis: a London multicentre case series

OBJECTIVE

In this multicentric study involving three London hospitals, we compared ANCA-positive and ANCA-negative cocaine-induced midline destructive lesions (CIMDL) patients to assess how presence of antineutrophil cytoplasmic antibodies (ANCA) may correlate with disease severity. Our secondary aims are to better classify etiology centered around ANCA positivity and, consequently, better disease management.

METHODS

A retrospective review was performed to identify patients with CIMDL seen between January 2019 and December 2022. Population data including age, sex, presentation, endoscopic findings, duration of cocaine use and active use of cocaine, type of treatment, laboratory (including ANCA serology), radiological, and histological findings were collected.

RESULTS

Forty CIMDL patients (25 male, median age of 42 years) were identified. The majority of them (72.5%) presented with either a septal perforation, a saddle nose deformity (22.5%), and/or a palatal fistula (20.0%). ANCA was positive in 71.1% of cases (66.7% p-ANCA). No statistically significant differences in the general characteristics, type of treatment, laboratory results, radiological or histological findings were observed when comparing ANCA-positive and ANCA-negative CIMDL patients or when comparing p-ANCA and c-ANCA patients. Similarly, no statistically significant difference was obtained when comparing the pattern of distribution of lesions between the two groups.

CONCLUSIONS

A large percentage of CIMDL patients showed positive ANCA test (71.1%) and in the majority of the cases a p-ANCA pattern specifically targeting PR3 (p-ANCA, PR3 + MPO-). However, ANCA positivity or presence of a specific ANCA pattern was not associated with more severe presentation or more aggressive disease. Given its similarities to granulomatosis with polyangiitis (GPA), we recommend the use of the term "cocaine-induced ENT pseudo-GPA" instead of CIMDL.

LEVEL OF EVIDENCE

IV Laryngoscope, 134:2609-2616, 2024.

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.

Staphylococcus aureus Infection-Related Glomerulonephritis with Dominant IgA Deposition

Since 1995, when we reported the case of a patient with glomerulonephritis with IgA deposition that occurred after a methicillin-resistant Staphylococcus aureus (MRSA) infection, many reports of MRSA infection-associated glomerulonephritis have accumulated. This disease is being systematized as Staphylococcus infection-associated glomerulonephritis (SAGN) in light of the apparent cause of infection, and as immunoglobulin A-dominant deposition infection-related glomerulonephritis (IgA-IRGN) in light of its histopathology. This glomerulonephritis usually presents as rapidly progressive glomerulonephritis or acute kidney injury with various degrees of proteinuria and microscopic hematuria along with an ongoing infection. Its renal pathology has shown several types of mesangial and/or endocapillary proliferative glomerulonephritis with various degrees of crescent formation and tubulointerstitial nephritis. IgA, IgG, and C₃ staining in the mesangium and along the glomerular capillary walls have been observed on immunofluorescence examinations. A marked activation of T cells, an increase in specific variable regions of the T-cell receptor β-chain-positive cells, hypercytokinemia, and increased polyclonal immune complexes have also been observed in this glomerulonephritis. In the development of this disease, staphylococcal enterotoxin may be involved as a superantigen, but further investigations are needed to clarify the mechanisms underlying this disease. Here, we review 336 cases of IgA-IRGN and 218 cases of SAGN.

Acute interstitial nephritis and PR3-ANCA following reintroduction of pembrolizumab: a case report

Renal toxicity from immune checkpoint inhibitors (ICIs) is an increasingly recognized cause of acute kidney injury among patients with cancer. ICI-associated acute kidney injuries typically present as acute interstitial nephritis and the timing of onset is highly variable. Herein, we present a case of a patient with relapsed metastatic melanoma previously treated with pembrolizumab who developed grade 3 immune-related renal toxicity after reintroduction of the same ICI, secondary to acute interstitial nephritis with accompanying high PR3-antineutrophil cytoplasmic antibody titer. The patient improved after steroid treatment and discontinuation of pembrolizumab. This case highlights the importance of not excluding ICI-related nephrotoxicity as a possible cause of renal failure, including in those who previously tolerated ICI treatment, since it is a treatable entity.

2020 international consensus on ANCA testing beyond systemic vasculitis

This document follows up on a 2017 revised international consensus on anti-neutrophil cytoplasm antibodies (ANCA) testing in granulomatosis with polyangiitis and microscopic polyangiitis and focuses on the clinical and diagnostic value of ANCA detection in patients with connective tissue diseases, idiopathic interstitial pneumonia, autoimmune liver diseases, inflammatory bowel diseases, anti-glomerular basement membrane (GBM) disease, infections, malignancy, and during drug treatment. Current evidence suggests that in certain settings beyond systemic vasculitis, ANCA may have clinical, pathogenic and/or diagnostic relevance. Antigen-specific ANCA targeting proteinase-3 and myeloperoxidase should be tested by solid phase immunoassays in any patient with clinical features suggesting ANCA-associated vasculitis and in all patients with anti-GBM disease, idiopathic interstitial pneumonia, and infective endocarditis associated with nephritis, whereas in patients with other aforementioned disorders routine ANCA testing is not recommended. Among patients with autoimmune liver diseases or inflammatory bowel diseases, ANCA testing may be justified in patients with suspected autoimmune hepatitis type 1 who do not have conventional autoantibodies or in case of diagnostic uncertainty to discriminate ulcerative colitis from Crohn's disease. In these cases, ANCA should be tested by indirect immunofluorescence as the target antigens are not yet well characterized. Many questions concerning the optimal use of ANCA testing in patients without ANCA-associated vasculitis remain to be answered.

Laboratory Assessment of Patients with Suspected Rheumatic Musculoskeletal Diseases: Challenges and Pitfalls

Current patient care in rheumatology relies primarily on a combination of traditional clinical assessment and standard laboratory tests. Investigators seek to discover new biomarkers and novel technologies to boost the research in this field. Mechanistic biomarkers such as cytokines, cell types, antibodies, signaling molecules, are rooted in the mechanism underlying the disease and can guide the clinical management of the disease. Conversely, descriptive biomarkers are byproducts of the disease process, depict the state of a disease but are not involved in its pathogenesis. In this article, we reviewed the field of common laboratory biomarkers in rheumatology, highlighting both their descriptive or mechanistic value as well as their role in clinical practice.

[Vasculitis mimics]

Vasculitis mimics need to be differentiated from primary and secondary vasculitides as described in the Chapel Hill nomenclature. The clinical symptomatology resembles that of vasculitis of small and medium, rarely also large vessels and hence imitates the classical vasculitic disorders. Pathogenetically, the causes are partly genetic mutations, embolization syndromes, infections and substance abuse. Also, B‑cell lymphomas can mimic vasculitis. The present manuscript summarizes the vasculitis mimics.

Genetics and pathogenesis of small-vessel vasculitis

Small-vessel vasculitides are uncommon autoimmune diseases characterised by inflammation and necrosis of arterioles, capillaries and venules, frequently described as various (previously eponymous) clinical syndromes. Some are associated with vessel wall immune complex deposition, whereas others are pauci-immune but paradoxically often associated with circulating anti-neutrophil cytoplasmic antibodies (ANCA). Most is known about the pathogenesis of the pauci-immune ANCA-associated syndromes, which are gradually becoming better understood with regard to their genetic predisposition and the critical pathways mediating disease initiation, as well as their particular phenotypic features. Through better understanding of key cellular and molecular players, we have been able to develop novel biomarkers and treatment strategies, which should translate to improved diagnostics, treatment protocols and, ultimately, better patient outcomes. These conditions are treatable but not yet curable, although it is clear that patients may follow different disease courses, which for some include restoration of their pre-morbid immune status.

Bartonella Endocarditis Mimicking Crescentic Glomerulonephritis with PR3-ANCA Positivity

Bartonella henselae is a fastidious organism that causes cat scratch disease, commonly associated with fever and lymphadenopathy but, in rare instances, also results in culture-negative infectious endocarditis. We describe a patient who presented with flank pain, splenic infarct, and acute kidney injury with an active urinary sediment, initially suspicious for vasculitis, which was subsequently diagnosed as B. henselae endocarditis. Bartonella endocarditis may present with a crescentic glomerulonephritis (GN) and elevated PR3-ANCA antibody titers, mimicking ANCA-associated GN, with 54 cases reported in the literature. Unique to our case in this series is a positive PR3-ANCA antibody despite a negative IIF-ANCA. Thus, the presentation of Bartonella can mimic ANCA-associated GN, and renal biopsy showing immune complex deposition is critical for diagnosis and appropriate treatment.

Clinical manifestations of granulomatosis with polyangiitis: key considerations and major features

BACKGROUND

Granulomatosis with polyangiitis (GPA) presents a wide spectrum of manifestations from the common respiratory symptoms to infrequent neurological and cardiac complications. The challenge in diagnosis and management makes the rapidly progressive disorder one of the most challenging dilemmas in clinical medicine.

METHOD

An extensive electronic literature search was done using multiple databases (e.g. PubMed) from January 2007 to August 2017 to gather information on the etiopathogenesis, clinical presentation, and current treatment management plan of GPA. The language used was English. Search items included 'Granulomatosis with Polyangiitis symptoms,' 'Wegener's Granulomatosis,' and 'Treatment of Granulomatosis with Polyangiitis' for the databases. Inclusion criteria consisted of published articles in the English language which reported on the clinical manifestations of GPA, as well as on the treatment of the disease. Exclusion criteria included articles that: (1) did not specifically report on GPA vasculitis but also focused on discussion of other vasculitis such as MPA or Churg-Strauss; (2) reported on treatment/symptoms of GPA prior to 2007.

RESULT

This review provides an overview of work undertaken in key areas of GPA research, including its complex multifactorial etiology, clinical manifestations, treatment strategies, and treatment-related adverse effects.

CONCLUSION

Major advances in the understanding and treatment of GPA over recent decades have contributed to the notable decline in morbidity and mortality of patients. The ultimate goal is an improved prognosis through outcome measures which assesses the disease control with minimal adverse effects of intensive immunosuppressive regimens, an integral part of the clinical approach to improve the quality of life of GPA patients.

Anti-neutrophil cytoplasm antibodies (ANCA): Recent methodological advances-Lead to new consensus recommendations for ANCA detection

The current practice for detection of anti-neutrophil cytoplasm antibodies (ANCA) directed against proteinase 3 (PR3) and myeloperoxidase (MPO) has been screening by indirect immunofluorescence (IIF) followed by an antigen specific tests for PR3- and MPO-ANCA. However, ANCA diagnostics have undergone many technical developments that have affected the 1999 international consensus recommendations, and lead to a revision of the existing ANCA detection strategy. Recent European multicentre studies have compared the diagnostic performance of various ANCA detection methods and demonstrated that PR3- and MPO-ANCA immunoassays yielded the highest diagnostic accuracy. New guidelines for ANCA testing have been developed based on these data. According to the revised 2017 international consensus recommendations, testing for ANCA in small vessel vasculitis can be done by PR3- and MPO-ANCA immunoassays, without the categorical need for IIF. Thus, IIF can be discarded completely, or can be used as confirmation assays instead a screening test. Clearly, though, the new testing strategy for ANCA in vasculitis must identify the ANCA target antigen, as PR3- and MPO-ANCA serotype correlate well with disease expression. Furthermore, recent studies have shown that AAV can be classified based on ANCA serotype, since PR3- and MPO-ANCA- diseases are strongly associated with distinguishable genetic alleles, different clinical and histological features. ANCA presence and the antigen specificity also may have important value as a prognostic factor and may serve as a guide for immunosuppressive therapy. In the current review, we summarize the novelties in ANCA testing, present the 2017 revised international consensus on ANCA testing in vasculitis, evaluate the diagnostic significance of ANCA, and discuss the role of ANCA serotypes in the diagnostic work-up of patients with AAV.

ANCA-associated vasculitis with renal involvement

Systemic vasculitis is a rare but severe group of diseases characterized by inflammation and necrosis of blood vessels. The size of the vessel affected varies among the different forms of vasculitis and there are three main subgroups: large, medium and small vessel vasculitis. Among small vessel vasculitis, the antineutrophil cytoplasmic antibody (ANCA)-associated forms are of particular importance. This subgroup includes: microscopic polyangiitis, granulomatosis with polyangiitis (Wegener's), eosinophilic granulomatosis with polyangiitis (Churg-Strauss) and the form limited to the kidney. ANCA are serum autoantibodies directed against proteins present in the cytoplasmic granules of neutrophils and represent the serological markers of small vessel vasculitis. Renal involvement is present in the majority of patients with ANCA-associated vasculitis (AAV) and the consequences of a missed or delayed diagnosis of renal vasculitis are potentially life threatening. Patient survival and the risk of end-stage renal disease are closely associated with renal function at presentation. The gold standard for diagnosis remains renal biopsy. In 2010, a new histopathological classification based on the percent of normal glomeruli, cellular crescent or global sclerotic glomeruli was proposed. The aim of this classification was to predict the renal prognosis. Nowadays, remission can be achieved and maintained in most cases with a combination of high-dose steroid and immunosuppressive drugs. This therapy has to be continued for at least 24 months after a substantial remission has been obtained because early cessation of treatment is associated with an increased risk of relapse. For this reason, patients should be regularly monitored in order to promptly diagnose and treat a possible recurrence of AAV. This review will focus on kidney involvement in AAV with an overview of the clinical-pathological characteristics and therapeutic strategy for these conditions.

Variability in Testing for Antineutrophil Cytoplasmic Antibodies: A Survey of Participants in the College of American Pathologists Proficiency Testing Program

CONTEXT

-Variability in testing for antineutrophil cytoplasmic antibodies (ANCAs) contributes to confusion and controversy related to testing for vasculitis and other ANCA-associated diseases.

OBJECTIVES

-To survey laboratory testing practices regarding ANCA testing and to investigate differences in testing algorithms.

DESIGN

-Supplemental questions were sent to the 333 laboratories participating in the College of American Pathologists proficiency testing program for ANCA as part of the Special Immunology S2 Survey.

RESULTS

-A total of 315 laboratories submitted responses to the supplemental questions. Only 88 of 315 participants (28%) reported using a combination of indirect immunofluorescence (IFA) and enzyme immunoassay (EIA) techniques as recommended by current guidelines, with a few additional labs using IFA and multiplex bead assay as an acceptable alternative to EIA. Other labs reported using only IFA, EIA, or multiplex bead assays.

CONCLUSIONS

-A wide variety of testing algorithms are in use for ANCA testing despite evidence to suggest that a combination of IFA and EIA testing provides the most comprehensive information. Laboratories should inform clinicians clearly about testing practices and utility of testing in specific disease states.

[Cutaneous and mucosal manifestations associated with cocaine use]

Complications due to cocaine are a public health problem. The typical cutaneous disease is leukocytoclastic vasculitis and/or thrombotic vasculopathy affecting mainly the ears. No intense systemic involvement is usually present, but there may be several cutaneous, mucosal and systemic manifestations. Other findings associated as arthralgia, neutropaenia or agranulocytosis, low titer positive antinuclear antibodies, antiphospholipid antibody positivity and neutrophil cytoplasmic antibodies against multiple antigens help the diagnosis. This disease requires a clinical suspicion with a clinical history, a complete physical examination and a broad differential diagnosis for an early and correct diagnosis. The course is usually self-limited. In most cases the only treatment is to discontinue the use of cocaine associated with symptomatic treatment, no proven benefit of systemic corticosteroids.

Antineutrophil Cytoplasmic Antibody Induction due to Infection: A Patient with Infective Endocarditis and Chronic Hepatitis C

While antineutrophil cytoplasmic antibody (ANCA) is often used as a diagnostic marker for certain vasculitides, ANCA induction in the setting of infection is much less common. In the case of infective endocarditis, patients may present with multisystem disturbances resembling an autoimmune process, cases that may be rendered even trickier to diagnose in the face of a positive ANCA. Though not always straightforward, distinguishing an infective from an inflammatory process is pivotal in order to guide appropriate therapy. We describe an encounter with a 43-year-old male with chronically untreated hepatitis C virus infection who featured ANCA positivity while hospitalized with acute bacterial endocarditis. His case serves as a reminder of two of the few infections known to uncommonly generate ANCA positivity. We also summarize previously reported cases of ANCA positivity in the context of endocarditis and hepatitis C infections.

CanVasc Recommendations for the Management of Antineutrophil Cytoplasm Antibody-associated Vasculitides

Objective.

The Canadian Vasculitis research network (CanVasc) is composed of physicians from different medical specialties and researchers with expertise in vasculitis. One of its aims is to develop recommendations for the diagnosis and management of antineutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV) in Canada.

Methods.

Diagnostic and therapeutic questions were developed based on the results of a national needs assessment survey. A systematic review of existing non-Canadian recommendations and guidelines for the diagnosis and management of AAV and studies of AAV published after the 2009 European League Against Rheumatism/European Vasculitis Society recommendations (publication date: January 2009) until November 2014 was performed in the Medline database, Cochrane library, and main vasculitis conference proceedings. Quality of supporting evidence for each therapeutic recommendation was graded. The full working group as well as additional reviewers, including patients, reviewed the developed therapeutic recommendations and nontherapeutic statements using a modified 2-step Delphi technique and through discussion to reach consensus.

Results.

Nineteen recommendations and 17 statements addressing general AAV diagnosis and management were developed, as well as appendices for practical use, for rheumatologists, nephrologists, respirologists, general internists, and all other healthcare professionals more occasionally involved in the management of patients with AAV in community and academic practice settings.

Conclusion.

These recommendations were developed based on a synthesis of existing international guidelines, other published supporting evidence, and expert consensus considering the Canadian healthcare context, with the intention of promoting best practices and improving healthcare delivery for patients with AAV.

The kidneys and ANCA-associated vasculitis: from pathogenesis to diagnosis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are a group of pauci-immune small vessel vasculitides that often affect the kidneys manifesting as rapidly progressive glomerulonephritis. Although the exact pathogenesis of AAV is not fully known, evidence from in vitro, in vivo and clinical studies all point to the involvement of ANCA in the pathogenesis of AAV. In this review, we highlight the contributory roles played by various factors (e.g. genetics, environment, B and T-regulatory cells, toll-like receptors, etc.) in the pathogenesis of AAV. Furthermore, we discuss renal involvement in AAV in terms of clinical features and the various histopathological classification patterns, which are also known to be of prognostic importance. We also present information on useful imaging techniques for localizing kidney and other organ system involvement in AAV, and also on novel laboratory methods and assays useful for rapid and more specific determination of patients' ANCA status. Finally, we demonstrate evidence on novel serum biomarkers that have been shown to correlate with disease activity in AAV.

Pulmonary Limited MPO-ANCA Microscopic Polyangiitis and Idiopathic Lung Fibrosis in a Patient with a Diagnosis of IgA Nephropathy

We present a case of a male patient with chronic renal insufficiency, due to crescentic glomerulonephritis with IgA deposits, who successively developed (idiopathic) thrombocytopenic purpura (ITP) and MPO-ANCA microscopic polyangiitis (MPA) with pulmonary fibrosis. The patient presented with cough, weight loss, and dyspnea on exertion. CT imaging and pulmonary function tests were compatible with interstitial pneumonitis with pulmonary fibrosis. Laboratory results showed high MPO-ANCA titers; the urinary sediment was bland. The patient was treated successfully with cyclophosphamide and methyl-prednisolone. This unique case illustrates the diagnostic and therapeutic challenges of an unusual presentation of microscopic polyangiitis presenting first as isolated kidney disease with recurrence in the form of pneumonitis without renal involvement, in association with renal IgA deposits and ITP as coexisting autoimmune conditions.

A dual-fixed neutrophil substrate improves interpretation of antineutrophil cytoplasmic antibodies by indirect immunofluorescence

OBJECTIVES

To determine whether the addition of a formalin-fixed neutrophil substrate could improve interpretation and prediction of autoantigenic specificity in antineutrophil cytoplasmic antibody (ANCA) testing.

METHODS

Routine diagnostic samples sent for ANCA testing were analyzed prospectively on a dual substrate of both ethanol- and formalin-fixed neutrophils. Positive samples on ethanol-fixed neutrophils were deemed "typical" if formalin-fixed neutrophils also stained, and "atypical" if not. Indirect immunofluorescence (IIF) results were correlated with antimyeloperoxidase (MPO) and anti-proteinase 3 (PR3) results with an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Of 1,426 samples, 201 from unique patients were ANCA-positive (200 on IIF, 1 on ELISA alone). Thirty-two (45%) of 71 typical ANCA staining patterns were positive for either an anti-MPO or anti-PR3 antibodies, whereas only one (0.8%) of 129 atypical patterns was ELISA-positive, in a patient without systemic vasculitis. Only one (3%) of 34 ELISA-positive samples had a negative IIF-ANCA (1/1,426 patients, 0.07%), and this patient did not have vasculitis.

CONCLUSIONS

Concomitant staining on formalin fixation of IIF-positive ethanol-fixed ANCA samples improves the interpretation of ANCA testing and is predictive of vasculitis autoantigens MPO and PR3.

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

The 2012 renewed Chapel Hill Consensus Conference (CHCC) officially named three clinicopathological entities, i.e. granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA), as major variants of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV). Recent genetic and cohort studies revealed the need for further differentiation between the entities, for example regarding differences in outcome. As well as ANCA reactivity, upper and lower airway disease were found to be differentiating factors for AAV variants, improving prognostic ability regarding relapse prediction and associated clinical features. Extravascular granulomatosis, or "granuloma", which describes both clinically relevant granulomatous manifestations and histopathologically documented granulomatous inflammation, is characteristic of localized and systemic GPA, but not MPA. This review summarizes new knowledge regarding granuloma in the head and neck region of AAV, its histomorphological equivalents in the upper and lower respiratory tract, and evidence for a granulomatous phenotype of a persistent localized GPA variant. This comprises the development of disease activity and damage scores for extravascular lesions in the ear, nose, and throat (ENT) regions, and imaging techniques. In addition, findings linking extravascular manifestations to granulomatous inflammation are described. We hypothesize that, as for ANCA, necrotizing granulomatous inflammation and its clinical manifestations are discriminators, assisting subclassification of AAV and/or GPA subphenotypes which will be useful both for designing clinical trials and for treating patients successfully.

Current understanding of the pathogenesis of granulomatosis with polyangiitis (Wegener's)

Granulomatosis with polyangiitis (Wegener's) (GPA) is a multisystem disease of unknown etiology, characterized by granulomata of the respiratory tract and systemic necrotizing vasculitis. Antineutrophil cytoplasmic antibodies (ANCA) with specificity for proteinase 3 (PR3) are a defining feature of this disease. GPA usually starts as a granulomatous disease of the respiratory tract and, in the majority of patients, progresses to systemic disease with PR3-ANCA-associated vasculitis. Today, epidemiological evidence indicates that GPA develops as a result of complex gene-environment interactions. The nature of these risk factors and pathogenic mechanisms involved, however, are only just beginning to be understood. Clinical data and in vitro experimental results point to the pathogenic pathways involved in tissue lesion development, in which ANCA, cellular immunity, neutrophils extracellular traps, fibroblasts, vascular endothelial cells and inflammatory mediators play a major role. Today, the pathophysiological significance of PR3-ANCA is still unclear and the pathogenic pathways leading to granuloma formation are not explained. New data unexpectedly suggest that the destruction of nasal cartilage in GPA is mainly mediated by fibroblasts that can be blocked by corticosteroids.

Systemic necrotizing vasculitis induced by isoniazid

A rare fatal case of antineutrophil cytoplasmic antibody-positive vasculitis induced by isoniazid is described.

High prevalence of IgA class anti-neutrophil cytoplasmic antibodies (ANCA) is associated with increased risk of bacterial infection in patients with cirrhosis

BACKGROUND & AIMS

Anti-neutrophil cytoplasmic antibodies (ANCA) are a non-uniform family of antibodies recognizing diverse components of neutrophil granulocytes. ANCA formation might be induced by protracted bacterial infections or probably reflect an abnormal immune response to commensal microorganisms. Bacterial infections are common complications in cirrhosis with high incidence of episodes caused by enteric organisms, therefore, we sought to study the presence and clinical importance of ANCA in cirrhosis.

METHODS

Sera of 385 patients with cirrhosis of different etiologies were assayed for ANCA of IgG, IgA, IgA1, IgA2, and secretory IgA subtypes by indirect immunofluorescence and ELISAs. The control group comprised 202 patients with chronic liver diseases without cirrhosis and 100 healthy subjects. In cirrhosis, a 2-year follow-up, observational study was conducted to assess a possible association between the presence of ANCA and clinically significant bacterial infections.

RESULTS

Prevalence of ANCA IgA was significantly higher in cirrhosis (52.2%) compared to chronic liver diseases (18.6%) or healthy controls (0%, p<0.001 for both). ANCA IgA subtyping assays revealed marked increase in the proportion of IgA2 subtype (46% of total ANCA IgA) and presence of the secretory component concurrently. Presence of ANCA IgA was associated with disease-specific clinical characteristics (Child-Pugh stage and presence of ascites, p<0.001). During a 2-year follow-up period, risk of infections was higher among patients with ANCA IgA compared to those without (41.8% vs. 23.4%, p<0.001). ANCA IgA positivity was associated with a shorter time to the first infectious complication (pLogRank <0.001) in Kaplan-Meier analysis and was identified as an independent predictor in multivariate Cox-regression analysis (HR:1.74, 95% CI: 1.18-2.56, p=0.006).

CONCLUSIONS

Presence of IgA type ANCA is common in cirrhosis. Involvement of gut mucosal immune system is in center of their formation and probably reflects sustained exposure to bacterial constituents.

[Secondary vasculitides and vasculitis mimics]

Secondary vasculitis is a form of vasculitis for which an underlying disease is known. Diseases associated with secondary vasculitis include infections, drug hypersensitivity, malignancy, rheumatoid arthritis, collagen vascular disease and sarcoidosis. Moreover, there are numerous conditions that can mimic vasculitis clinically, in laboratory testing, radiographically and in histopathology. It is evident that distinguishing primary vasculitis from secondary vasculitis and also vascular inflammation from non-vasculitic disorders (vasculitis mimics) has significant therapeutic implications.

Wegener's granulomatosis: a review of clinical features and an update in diagnosis and treatment

Wegener's granulomatosis (WG) is an idiopathic, systemic inflammatory disease characterized by necrotizing granulomatous inflammation and pauci-immune small-vessel vasculitis of upper and lower respiratory tract and kidneys. The condition affects both genders equally, although some inconsistent gender differences have been observed. The aetiology of WG remains unknown although a number of exogenous factors have been suggested to be of aetiological relevance. Most clinical characteristics of this disease are non-specific, making clinical diagnosis challenging. Histopathological examination of lesional and peritoneal tissue is not pathognomonic, but is an essential investigation to confirm the presence of disease and exclude other disorders. At present, despite the increasingly wide range of potential therapies, cyclophosphamide plus corticosteroids remain the most recognized and effective means of inducing and sustaining remission of WG.

Concomitant drug- and infection-induced antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis with multispecific ANCA

OBJECTIVE

To report the first case of concomitant drug- and infection-induced antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) in a patient treated with propylthiouracil (PTU) and suffering from tuberculosis.

PRESENTATION AND INTERVENTION

A 28-year-old woman with PTU-treated hyperthyroidism presented with fever, purpura, pulmonary cavitations and ANCA to myeloperoxidase, bactericidal/permeability-increasing protein (BPI), proteinase-3 and elastase. Skin histopathology confirmed vasculitis. However, sputum examination revealed Mycobacterium tuberculosis. Remission was achieved after PTU withdrawal and treatment with antituberculosis drugs.

CONCLUSION

Our case confirmed that BPI-ANCA are elevated in active tuberculosis. Multispecific ANCA were helpful for the diagnosis of concomitant PTU- and M. tuberculosis-induced AAV.

Complements do not lie

A 74-year-old patient presented with constitutional symptoms and was found to have acute kidney injury. He was known to have a prosthetic aortic valve. He was febrile with splenomegaly and vasculitic lesions on both hands. Nephritic screen revealed strongly positive cytoplasmic-antineutrophil cytoplasmic antibodies (c-ANCA). Differential diagnosis thus included a small vessel vasculitis or infective endocarditis. Transoesophageal echocardiography demonstrated no vegetations and serial blood cultures were negative. Immunosuppression for presumed granulomatosis with polyangiitis (Wegeners granulomatosis) was therefore instituted. The patient deteriorated, requiring multi-organ support. Renal biopsy showed a proliferative glomerulopathy and complements were low. Atypical screen for culture negative endocarditis revealed a strongly positive IgG-antibody titre against Bartonella henselae. Immunosuppression was discontinued and treatment for chronic Bartonellosis commenced. The patient made a remarkable recovery. His renal function quickly returned to normal, and ANCA titres and complements normalised. He was discharged home after completing a 6 week course of antibiotic therapy.

Otolaryngologic manifestations of antineutrophil cytoplasmic antibody-associated vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is characterized by systemic necrotizing vasculitis, and patients fall into 2 groups: those with proteinase 3-ANCA and those with myeloperoxidase-ANCA. As infections are a trigger of ANCA-associated vasculitis, this disease tends to localize in areas around the upper airway. In this study, the authors compared ear and nasal symptoms between patients with proteinase 3-ANCA and those with myeloperoxidase-ANCA. We undertook a retrospective case series study of 34 patients diagnosed with ANCA-associated vasculitis. The otologic symptoms were divided into 3 types: chronic otitis media, secretory otitis media, and sensorineural hearing loss. Chronic otitis media was more common in patients with proteinase 3-ANCA (P = .001), whereas secretory otitis media was more frequently found in patients with myeloperoxidase-ANCA (P = .007). Crust formation (P = .001), saddle nose (P = .024), and sinusitis (P = .001) were more common in patients with proteinase 3-ANCA than in those with myeloperoxidase-ANCA. Marked differences were observed in the disease spectrum between the 2 ANCA groups.

Biomarkers of endothelial cell activation: candidate markers for drug-induced vasculitis in patients or drug-induced vascular injury in animals

There is a pressing need for vascular biomarkers for studies of drug-induced vasculitis in patients and drug-induced vascular injury (DIVI) in animals. We previously reviewed a variety of candidate biomarkers of endothelial cell (EC) activation (Zhang et al., 2010). Now we update information on EC activation biomarkers from animal data on DIVI and clinical data of vasculitic patients, particularly patients with primary antineutrophil cytoplasmic autoantibody (ANCA)-associated small vessel vasculitis (primary AAVs), including Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome and necrotizing crescentic glomerulonephritis. Drug-associated ANCA-positive small vessel vasculitis (drug-AAVs) can closely resemble primary AAVs, suggesting the large overlap between primary idiopathic systemic vasculitis and drug-induced vasculitis. AAVs in patients and DIVI in animals vary considerably; however, there is close resemblance between AAVs and DIVI in some respects: (1) the immunopathogenetic mechanisms (activation of primed neutrophils, ECs and T cells by ANCA in patients and activation of ECs, mast cells, and macrophages by drugs in animals); (2) the morphologic changes (fibrinoid necrosis of the vessel wall and neutrophilic infiltration); (3) the preferable sites (small arteries, arterioles, capillaries and venules); and (4) elevation of vascular biomarkers suggestive of an endothelial origin. The present review discusses soluble and cell component biomarkers and provides a rationale for the potential utility of EC activation biomarkers in nonclinical and clinical studies during new drug development. Further investigation, however, is needed to assess their potential utility.

Increased expression of Toll-like receptors by monocytes and natural killer cells in ANCA-associated vasculitis

Introduction

Toll-like receptors (TLRs) are a family of receptors that sense pathogen associated patterns such as bacterial cell wall proteins. Bacterial infections are associated with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV). Here, we assessed the expression of TLRs 2, 4, and 9 by peripheral blood leukocytes from patients with AAV, and investigated TLR mediated responses ex vivo.

Methods

Expression of TLRs was determined in 38 AAV patients (32 remission, 6 active disease), and 20 healthy controls (HC). Membrane expression of TLRs 2, 4, and 9, and intracellular expression of TLR9 by B lymphocytes, T lymphocytes, NK cells, monocytes and granulocytes was assessed using 9-color flowcytometry. Whole blood from 13 patients and 7 HC was stimulated ex vivo with TLR 2, 4 and 9 ligands and production of cytokines was analyzed.

Results

In patients, we observed increased proportions of TLR expressing NK cells. Furthermore, patient monocytes expressed higher levels of TLR2 compared to HC, and in a subset of patients an increased proportion of TLR4⁺ monocytes was observed. Monocytes from nasal carriers of Staphylococcus aureus expressed increased levels of intracellular TLR9. Membrane expression of TLRs by B lymphocytes, T lymphocytes, and granulocytes was comparable between AAV patients and HC. Patients with active disease did not show differential TLR expression compared to patients in remission. Ex vivo responses to TLR ligands did not differ significantly between patients and HC.

Conclusions

In AAV, monocytes and NK cells display increased TLR expression. Increased TLR expression by these leukocytes, probably resulting from increased activation, could play a role in disease (re)activation.

Conditions in subjects with rheumatic diseases: pulmonary manifestations of vasculitides

Pulmonary involvement is a common complication of vasculitides, especially small vessel vasculitides. This review provides an overview of vasculitic manifestations of the lung as well as of other organs involved in vasculitides. Furthermore, it provides the diagnostic procedures required to asses a patient with vasculitic lung involvement and gives an overview of current treatment strategies.

Pyrexia of unknown origin and pulmonary fibrosis as a presentation of MPO-ANCA associated vasculitis

The authors report the case of a 72-year-old man presenting with chronic dyspnoea and pyrexia of unknown origin (PUO). After extensive investigation, he was found to have pulmonary fibrosis with usual interstitial pneumonia pattern on high-resolution CT imaging and positive myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) with no infectious cause or other evidence of vasculitis organ involvement. His pyrexia and symptoms settled with oral systemic corticosteroid treatment. To the authors' knowledge this is the first case of MPO-ANCA positive vasculitis presenting as PUO and pulmonary fibrosis alone. The authors review the recent literature regarding the association of pulmonary fibrosis with ANCA-positive vasculitides with regards to pathogenesis, prognosis and treatment.

Unusual extracardiac manifestations of isolated native tricuspid valve endocarditis

Isolated native tricuspid valve endocarditis (TVE) in non-intravenous drug users is a very rare condition. We describe an unusual presentation of Enterococcus faecalis TVE associated with spondylodiscitis, positive cytoplasmic antineutrophil cytoplasmic antibodies and antiproteinase-3 antibodies vasculitic rash in an otherwise healthy patient with no history of intravenous drug use or underlying cardiac abnormalities. A high index of clinical suspicion is required in patients presenting with unusual features and pyrexia of unknown origin. Simple tests including serial blood cultures and echocardiography may help to establish the correct diagnosis and commence appropriate treatment.

A patient with intravascular lymphoma presenting with cerebral infarction and a high serum MPO-ANCA level

A 74-year-old woman presented with multiple brain infarctions, an inflammatory reaction, and a high serum titer (414 U/ml) of myeloperoxidase-specific antineutrophil cytoplasmic antibody (MPO-ANCA) with no hematological abnormalities. After the inflammation and ANCA titers were resolved with steroid therapy for suspected microscopic polyangiitis, hemophagocytic syndrome developed. Biopsies revealed non-Hodgkin's intravascular lymphoma (IVL). The flare of IVL with negative serum ANCA suggested that the initial high serum MPO-ANCA had not originated from tumor cells.