Monitoring proteinase 3 antineutrophil cytoplasmic antibodies for detection of relapses in small vessel vasculitis

Do Relapses Follow ANCA Rises? A Systematic Review and Meta-Analysis on the Value of Serial ANCA Level Evaluation

Objectives

ANCA-vasculitis (AAV) patients frequently suffer from relapses and risk subsequent organ damage. There is much debate on the value of serial ANCA level evaluation to monitor disease activity. We aimed to evaluate the association between ANCA rises and disease relapses at (I) moment of the rise, (II) within 6 months or (III) within a year from the rise.

Methods

3 databases (MEDLINE, EMBASE, COCHRANE) were searched from 1993 through September 2021. We included studies that reported relapse incidence within 12 months after an ANCA rise measured by antigen-specific immunoassays in peripheral blood of AAV patients in remission. Quality assessment was performed using QUADAS-2. Finally, a meta-analysis was carried out to estimate average OR using a random effects model.

Results

Twenty unique studies were included. The methodological quality was limited due to risk of selection bias. An ANCA rise often preceded a disease relapse within 6 months (OR 3.65, 95% CI 1.66–8.03) and less often within 12 months (OR 2.88, 95% CI 1.21–6.88), while it was not indicative of a concurrent relapse (OR 0.13, 95% CI 0.03–0.53). Once a relapse is diagnosed, ANCA is significantly more often present than not (OR 10.80, 95% CI 3.82–30.55). As expected based on clinical, technical and methodological variability between studies, there was substantial heterogeneity across studies in all analyses (I2 = 70–87%).

Conclusion

In previously ANCA-positive patients, the ANCA test is often positive upon clinical suspicion of a disease relapse. Patients with a rise in ANCA are at risk of encountering disease relapses in the upcoming 6 or 12 months.

Serological testing in small vessel vasculitis

Serological analysis has a central role in the diagnostic work-up of patients with suspected small vessel vasculitis, both for establishing a specific diagnosis and for the monitoring of response to therapy. Autoantibodies can be detected in all forms of primary small vessel vasculitis as well as in the most common forms of secondary vasculitis. For primary vasculitis the most important serological test is for ANCA. ANCA can be found in 75-95% of patients with pauci-immune small vessel vasculitis leading to this subgroup of vasculitides being named ANCA associated vasculitis. ANCA levels often follow this disease course, but the value of serial ANCA testing is controversial. Other important autoantibodies in primary small vessel vasculitis are anti-glomerular basement membrane antibodies, anti-C1q, anti-galactose deficient IgA and cryoglobulins. A wide variety of systemic inflammatory diseases and infections can be complicated by small vessel vasculitis and detected by serological testing. Important examples are SLE, rheumatoid arthritis, Hepatitis C and HIV.

Central Nervous System Involvement in ANCA-Associated Vasculitis: What Neurologists Need to Know

Objective: To provide a comprehensive review of the central nervous system (CNS) involvement in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), including the pathogenesis, clinical manifestations, ancillary investigations, differential diagnosis, and treatment. Particular emphasis is placed on the clinical spectrum and diagnostic testing of AAV.

Recent Findings: AAV is a pauci-immune small-vessel vasculitis characterized by neutrophil-mediated vasculitis and granulomatousis. Hypertrophic pachymeninges is the most frequent CNS presentation. Cerebrovascular events, hypophysitis, posterior reversible encephalopathy syndrome (PRES) or isolated mass lesions may occur as well. Spinal cord is rarely involved. In addition, ear, nose and throat (ENT), kidney and lung involvement often accompany or precede the CNS manifestations. Positive ANCA testing is highly suggestive of the diagnosis, with each ANCA serotype representing different groups of AAV patients. Pathological evidence is the gold standard but not necessary. Once diagnosed, prompt initiation of induction therapy, including steroid and other immunosuppressants, can greatly mitigate the disease progression.

Conclusions and Relevance: Early recognition of AAV as the underlying cause for various CNS disorders is important for neurologists. Ancillary investigations especially the ANCA testing can provide useful information for diagnosis. Future studies are needed to better delineate the clinical spectrum of CNS involvement in AAV and the utility of ANCA serotype to classify those patients.

Evidence Review: We searched Pubmed for relevant case reports, case series, original research and reviews in English published between Sep 1st, 2001 and Sep 1st, 2018. The following search terms were used alone or in various combinations: “ANCA,” “proteinase 3/PR3-ANCA,” “myeloperoxidase/MPO-ANCA,” “ANCA-associated vasculitis,” “Wegener's granulomatosis,” “microscopic polyangiitis,” “Central nervous system,” “brain” and “spinal cord”. All articles identified were full-text papers.

Hypersensitivity pneumonitis associated with azathioprine therapy in a patient with granulomatosis with polyangiitis

Granulomatosis with polyangiitis (GPA), an autoimmune disease characterized by inflammatory granulomas and necrotizing small-vessel vasculitis, primarily affects the respiratory tract and kidneys. Azathioprine (AZA) is a purine analog that is commonly used for maintaining GPA remission after induction therapy with cyclophosphamide. While the dose-dependent side effects of AZA are common and well known, hypersensitivity reactions such as pulmonary toxicity are rare. Here, we describe a case involving a 38-year-old man with GPA-associated pauci-immune crescentic glomerulonephritis who developed subacute hypersensitivity pneumonitis (HP) during AZA maintenance therapy. Five months after the initiation of AZA administration (100 mg/day), the patient was admitted with a 7-day history of cough, dyspnea, and fever. High-resolution computed tomography of the chest showed ill-defined centrilobular nodules and diffuse ground-glass opacities in both lung fields. Bronchoscopy with bronchoalveolar lavage was negative for infectious etiologies. A transbronchial lung biopsy specimen revealed poorly formed non-necrotizing granulomas. A chest radiograph obtained at 2 weeks after discontinuation of AZA showed normal findings. The findings from this case suggest that AZA-induced HP should be considered as a differential diagnosis when a patient with GPA exhibits fresh pulmonary lesions accompanied by respiratory symptoms during AZA therapy.

IgA- and SIgA anti-PR3 antibodies in serum versus organ involvement and disease activity in PR3-ANCA-associated vasculitis

Circulating immunoglobulin (Ig)A class anti-neutrophil cytoplasm antibodies (ANCA) directed against proteinase 3 (PR3) have been reported in ANCA-associated vasculitis (AAV) with mucosal involvement. However, secretory IgA (SIgA) PR3-ANCA has not been reported previously. In this study we compared serum levels of SIgA PR3-ANCA and IgA PR3-ANCA with IgG PR3-ANCA in relation to disease characteristics. Among 73 patients with AAV and PR3-ANCA at diagnosis, 84% tested positive for IgG PR3-ANCA, 47% for IgA-ANCA and 36% for SIgA PR3-ANCA at the time of sampling for the present study. IgA and IgG PR3-ANCA were represented similarly among patients with different organ manifestations, i.e. upper airway, lung or kidney at time of sampling. However, SIgA PR3-ANCA was significantly less represented among patients with upper airway involvement. During active disease, the proportions of IgA PR3-ANCA and SIgA PR3-ANCA-positive patients were significantly higher compared to inactive disease. Eight patients were sampled prospectively during 24 months from onset of active disease. In these patients, IgA PR3-ANCA and SIgA PR3-ANCA turned negative more often after remission induction compared to IgG PR3-ANCA. Our findings suggest that serum IgA PR3-ANCA and SIgA PR3-ANCA are related more closely to disease activity in AAV compared to IgG PR3-ANCA. Further studies are required to reveal if this has implications for disease activity monitoring. The mean number of PR3-ANCA isotypes increased along with disease activity, suggesting a global B cell activation during active disease.

Are anti-proteinase-3 ANCA a useful marker of granulomatosis with polyangiitis (Wegener's) relapses? Results of a retrospective study on 126 patients

OBJECTIVES

Predicting granulomatosis with polyangiitis (Wegener's) (GPA) relapses based on ANCA titers remains a source of debate. Our objective was to evaluate the relevance of monitoring PR3-ANCA titers for GPA management.

METHODS

This retrospective study included 126 patients fulfilling the 1990 ACR criteria for GPA and PR3-ANCA-positive at the time of diagnosis. Disease activity was assessed with BVAS/WG and Disease Extent Index. For each patient, a median of 12 serum samples was analyzed, i.e., one every 5.5months.

RESULTS

Induction therapy obtained remission in 88% of the patients. ANCA became negative by IF for 70/115 (60.9%) patients and by ELISA for 90/115 (78.3%). After median follow-up of 70months, 85/126 (67.5%) patients had 154 clinical relapses associated with cANCA and PR3-ANCA-positivity for 122 (79.2%) and 102 (66.2%) of them, respectively. Relapse-free survival was significantly longer for patients who remained PR3-ANCA-negative (HR 0.60 [95% CI 0.39-0.92], P=0.02). Individual ANCA-profile analysis revealed that, for 60% of GPA patients, clinical outcomes and ANCA-titer changes were closely associated, i.e., ANCA were always positive during relapses and negative during remission. The 35 patients with fluctuating ANCA-positivity during remission were in partial remission or had developed grumbling GPA.

CONCLUSION

Although ANCA were positive during most systemic relapses or residual disease, no strict clinical-immunological correspondence was observed for 25% of the patients. Thus, GPA management cannot be based on ANCA levels alone.

Current modalities in the diagnosis of pulmonary vasculitis

INTRODUCTION

This review addresses the pulmonary manifestations of the vasculitides, with a focus on diagnostic modalities. Haemorrhagic presentations (usually associated with nephritis: the pulmonary-renal syndrome) are the most common vasculitic cause of early death.

AREAS COVERED

The diagnostic modalities in the pulmonary vasculitides are reviewed, with a focus on primary systemic vasculitis. A literature search of original research and review articles on pulmonary vasculitides was undertaken using the PubMed database.

EXPERT OPINION

Small-vessel anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, especially granulomatosis with polyangiitis (Wegener's granulomatosis) are the most frequent causes of pulmonary vasculitis and typically present as nodules, alveolar infiltrates (haemorrhagic or not), cavities or tracheobronchial stenosis. Lung involvement is less common in large-vessel vasculitis when pulmonary vascular abnormalities can be seen. No single test is pathogonomonic and diagnosis requires integration of clinical, laboratory, imaging and histological findings. Treatment follows similar regimens to other vasculitic presentations, with glucocorticoids in conjunction with immunosuppressive agents, and management of intercurrent sepsis and the increased risk of cardiovascular and thromboembolic events. Prompt diagnosis and intensive treatment of pulmonary vasculitis is essential to improve early mortality and long-term outcomes.

Value of ANCA measurements during remission to predict a relapse of ANCA-associated vasculitis--a meta-analysis

OBJECTIVE

The value of repeated ANCA measurements among patients with an established diagnosis of ANCA-associated vasculitis (AAV) remains controversial. The aim of this study was to explore whether either of the two distinct patterns of ANCA values during remission, a rise in ANCA or persistently positive ANCA, predicted future relapse.

METHODS

MEDLINE and EMBASE searches were performed. Studies with at least 10 subjects with AAV from which both sensitivity and specificity of a rise in ANCA and/or persistent ANCA for future disease relapse could be calculated were included. Likelihood ratios were calculated for each study and pooled to arrive at summary estimates. I(2)-values were calculated as a measure of heterogeneity and meta-regression was used to explore sources of heterogeneity.

RESULTS

Nine articles on a rise in ANCA and nine articles on persistent ANCA were included. The summary estimates for positive likelihood ratio (LR(+)) and negative likelihood ratio (LR(-)) of a rise in ANCA during remission on subsequent relapse of disease were 2.84 (95% CI 1.65, 4.90) and 0.49 (95% CI 0.27, 0.87), respectively. The summary estimates for LR(+) and LR(-) of persistent ANCA during remission for subsequent disease relapse were 1.97 (95% CI 1.43, 2.70) and 0.73 (95% CI 0.50, 1.06), respectively. There was substantial between-study heterogeneity, which was partially explained by the frequency of ANCA measurements.

CONCLUSION

Among patients with AAV, a rise in or persistence of ANCA during remission is only modestly predictive of future disease relapse. There is limited use to serial ANCA measurements during disease remission to guide treatment decisions for individual patients with AAV.

Recent aspects of vasculitis and future direction

Vasculitis is pathologically identified as specific cellular inflammation, vessel destruction, and tissue necrosis. Current classifications of vasculitis such as the Chapel Hill Classification (CHCC) and American College of Rheumatology (ACR) guidelines are not sufficiently adequate for clinicians to diagnose vasculitis. The biomarkers that are currently in clinical use such as PR3-ANCA and MPO-ANCA, only help in diagnosing small vessel vasculitis and their sensitivity and specificity are not sufficient. However, recent developments related to the pathogenesis and etiopathogenesis of vasculitis have the potential to contribute to new and improved biomarkers. The determination of diverse roles of ANCA and synergistic effects of infection, genetic, environmental factors and drugs on pathogenesis is quite important. The demonstration of a new autoantibody directed to hLAMP-2 and the resemblance to some microbial structures, in addition to the determination of the possible roles of hepatitis B and C on vasculitis are important findings. These hints may lead to new biomarker developments, providing a better method to diagnose vasculitis. The evidence on T cell immunity as circulatory and lesional will likely contribute to the development of new drugs for vasculitis.

An approach to the diagnosis and management of systemic vasculitis

The systemic vasculitides are a complex and often serious group of disorders which, while uncommon, require careful management in order to ensure optimal outcome. In most cases there is no known cause. Multi-system disease is likely to be fatal without judicious use of immunosuppression. A prompt diagnosis is necessary to preserve organ function. Comprehensive and repeated disease assessment is a necessary basis for planning therapy and modification of treatment protocols according to response. Therapies typically include glucocorticoids and, especially for small and medium vessel vasculitis, an effective immunosuppressive agent. Cyclophosphamide is currently the standard therapy for small vessel multi-system vasculitis, but other agents are now being evaluated in large randomized trials. Comorbidity is common in patients with vasculitis, including the cumulative effects of potentially toxic therapy. Long-term evaluation of patients is important in order to detect and manage relapses.

Epitope shift of proteinase-3 anti-neutrophil cytoplasmic antibodies in patients with small vessel vasculitis

Anti-neutrophil cytoplasmic antibodies against proteinase 3 (PR3-ANCA) are used as diagnostic tools for patients with small vessel vasculitis (AASV). We have produced chimeric mouse/human PR3 molecules and investigate changes in reactivity over time and the possible relationship between epitope specificity and clinical course. Thirty-eight PR3-ANCA-positive patients diagnosed between 1990 and 2003 were followed until December 2005. Plasma was collected at each out-patient visit and older samples were retrieved retrospectively. Patients reacted with multiple epitopes at the time of diagnosis. At subsequent relapses 12 patients shifted reactivity, in 11 cases from epitopes located in the C-terminal towards epitopes in the N-terminal. Patients with reactivity against N-terminal parts of PR3 at diagnosis had a significantly lower relapse rate, 30% compared to 78% in the group with predominantly C-terminal reactivity (P = 0.04). The reactivity pattern did not correlate to outcome measured as death, end-stage renal disease or vasculitis activity index score (VDI) at 5 years. Further research is necessary to conclude if this is a general phenomenon.

Renal involvement in Wegener's granulomatosis

The term pauci-immune glomerulonephritis with vasculitis encompasses a group of auto-immune disorders, which includes Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome, and renal-limited vasculitis. Over the past few years, progress has been made in understanding the epidemiology and environmental and genetic risk factors of the role of antineutrophil cytoplasmic antibodies (ANCA) in kidney pathogenesis and the utilization of ANCA in diagnosis. However, certain aspects are still subject to debate including the classification and the place of ANCA in treatment.

Serial ANCA determinations for monitoring disease activity in patients with ANCA-associated vasculitis: systematic review

BACKGROUND

Antineutrophil cytoplasmic antibodies (ANCAs) are considered by some investigators to be sensitive markers of disease activity and have been suggested to predict relapse and guide therapeutic decisions. Studies using serial ANCA monitoring in patients with ANCA-associated vasculitis (AASV) have yielded controversial results during the last 15 years. To assess the diagnostic value of serial ANCA testing in the follow-up of patients with AASV, we conducted a systematic review of the available literature.

METHODS

Studies were identified by a comprehensive search of the PubMed and BIOSIS+/RRM databases, as well as hand searching. Method quality of all eligible studies was assessed with respect to external and internal validity according to established criteria for diagnostic studies.

RESULTS

Twenty-two studies met our inclusion criteria, including a total of 950 patients. Whereas generalizability was not a major problem, assessment of internal validity showed that only a minority of studies reported the combination of consecutive patient recruitment, prospective data collection, and independent determination of both index and reference tests, considered as the ideal for diagnostic test studies. Quantitative meta-analytic calculations were not conducted because of the presence of considerable method heterogeneity.

CONCLUSION

The presence of considerable methodological heterogeneity combined with methodological shortcomings with respect to internal validity in the majority of included studies preclude firm conclusions from the available literature concerning the clinical value of serial ANCA determinations for monitoring the follow-up of patients with AASV.

Update in the Diagnosis and Management of Pulmonary Vasculitis

The term vasculitis encompasses a number of distinct clinicopathologic disease entities, each of which is characterized pathologically by cellular inflammation and destruction of the blood vessel wall, and clinically by the types and locations of the affected vessels. While multiple classification schemes have been proposed to categorize and simplify the approach to these diseases, ultimately their diagnosis rests on the identification of particular patterns of clinical, radiologic, laboratory, and pathologic features. While lung involvement is most commonly seen with the primary idiopathic, small-vessel or antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides of Wegener granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome, one should remember that medium-vessel vasculitis (ie, classic polyarteritis nodosa), large-vessel vasculitis (ie, Takayasu arteritis), primary immune complex-mediated vasculitis (ie, Goodpasture syndrome), and secondary vasculitis (ie, systemic lupus erythematosus) can all affect the lung. However, for the purpose of this review, we will focus on the ANCA-associated vasculitides.

Glomerulonephritis due to antineutrophil cytoplasm antibody-associated vasculitis: an update on approaches to management

A patient with antineutrophil cytoplasm antibody-associated vasculitis frequently has multisystem disease and might present to a range of medical specialities. The manifestations that result in the greatest burden of morbidity and mortality are renal and pulmonary disease. In this review we will focus on rapidly progressive glomerulonephritis due to vasculitis, with specific reference to recent advances in our understanding of pathogenesis. The current standard of care for managing renal vasculitis, be it mild, moderate or severe, has largely been established in clinical trials of prednisolone, cyclophosphamide, methotrexate, azathioprine and plasma exchange. In addition to these, newer therapies such as mycophenolate mofetil and infliximab are being used more frequently. We will review the role of each of these approaches to management of small vessel vasculitis in 2005.