What you should know about PR3-ANCA. An introduction

Development of a scoring system for predicting the severity of ulcerative colitis

BACKGROUND AND STUDY AIMS

Monitoring disease activity in ulcerative colitis (UC) is critical in preventing long-term complications. This study aims to develop a scoring system using non-invasive indicators to predict endoscopic activities for ulcerative colitis (UC) patients.

PATIENTS AND METHODS

All enrolled patients with UC admitted to Shanghai Xinhua Hospital between June 2017 and January 2021 were enrolled, and their clinical data were retrospectively collected and a number of serological biomarkers concentrations were analyzed. Patients were categorized into mild and moderate-to-severe disease groups. Univariate and multivariate logistic regression was used to predict moderate-to-severe endoscopic activities, which were then incorporated into a nomogram to establish a prediction scoring model.

RESULT

Overall, 231 patients were divided into a mild group (n = 111, 48.0%) and a moderate-to-severe group (n = 120, 52.0%). The following variables were independently associated with the disease severity and were subsequently included into the prediction model: Proteinase 3 antineutrophil cytoplasmic antibody (PR3-ANCA), C-reactive protein (CRP), hemoglobin(Hb), IL-10, stool frequency ≥ 5 times/day and hematochezia. Incorporating these 6 factors, the nomogram showed good discrimination with C-index of 0.819 and reliable calibration. A scoring model was established with the area under the curve 0.818. Moreover, PR3-ANCA and CRP correlated with the duration of hospital stay.

CONCLUSION

We developed a predictive model for endoscopic disease activities by using noninvasive factors based on PR3-ANCA, CRP, Hb, IL-10, stool frequency and hematochezia. This prediction model might assist clinicians in managing patients with UC.

A challenging case of granulomatosis with polyangiitis with cardiac involvement: a rare case report

Background

Granulomatosis with polyangiitis (GPA), a systemic antineutrophil cytoplasmic antibody (ANCA) associated vasculitis, is characterized by inflammation of the small arteries, arterioles, and capillaries classically manifesting with glomerulonephritis and necrotizing granulomatous lesions of the upper and lower respiratory tract. With an incidence of approximately 12 cases per one million individuals per year it is an uncommon diagnosis that typically presents as frequent pulmonary and sinus infections; however, if left without definitive treatment progresses to more severe manifestations specifically hemoptysis and hematuria.

Case Description

This case report highlights a 15-year-old woman who had both classic and non-classic findings making the diagnosis challenging. Specifically, her age of presentation, improvement with anti-microbials, and coronary dilation were not classic. Additionally, her lab work was negative for the cytoplasmic subset antineutrophil cytoplasmic autoantibody (c-ANCA), but positive for serum anti-proteinase 3 antineutrophil cytoplasmic antibody (PR3-ANCA) which further delayed the ultimate diagnosis as this is typically c-ANCA positive.

Conclusions

Other systemic vasculitides, such as mucocutaneous lymph node disease, are associated with cardiac pathology necessitating further medical management and follow-up to prevent increased morbidity and mortality. Knowing this, we conclude that further evaluation for cardiac pathology would be prudent as part of the initial workup of patients with a diagnosis of GPA. Included is a brief review of available literature on GPA to emphasize the typical presentation, lab findings, and importance of early diagnosis.

ANCA Associated Vasculitis (AAV): A Review for Internists

Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) compromise a rare group of necrotizing small to medium vessel vasculitides that constitute three distinct disorders: granulomatosis with polyangiitis (GPA) (formerly known as Wegener's granulomatosis), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA) (formerly known as Churg-Strauss syndrome).AAV is characterized by the usual presence of circulating autoantibodies to the neutrophil proteins leukocyte proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA). These antibodies can activate neutrophils and the complement system resulting in vessel wall inflammation and damage.The clinical presentation of AAV varies from non-severe (non-life threatening) to severe often with potentially life-threatening multi-organ involvement. Early recognition and diagnosis are crucial. In the past two decades, advances in understanding the pathophysiology of AAV have led to development of new treatments and resulted in significant improvement in general outcomes and survival rates.This narrative review will focus on GPA and MPA. We will highlight clinical manifestations, diagnosis, disease monitoring, and treatment strategies in patients with AAV.

Lupus Vasculitis: An Overview

Lupus vasculitis (LV) is one of the secondary vasculitides occurring in the setting of systemic lupus erythematosus (SLE) in approximately 50% of patients. It is most commonly associated with small vessels, but medium-sized vessels can also be affected, whereas large vessel involvement is very rare. LV may involve different organ systems and present in a wide variety of clinical manifestations according to the size and site of the vessels involved. LV usually portends a poor prognosis, and a prompt diagnosis is fundamental for a good outcome. The spectrum of involvement ranges from a relatively mild disease affecting small vessels or a single organ to a multiorgan system disease with life-threatening manifestations, such as mesenteric vasculitis, pulmonary hemorrhage, or mononeuritis multiplex. Treatment depends upon the organs involved and the severity of the vasculitis process. In this review, we provide an overview of the different forms of LV, describing their clinical impact and focusing on the available treatment strategies.

Leukocytoclastic Vasculitis as a Rare Dermatologic Extraintestinal Manifestation of Ulcerative Colitis in an Elderly Patient with Positive PR3-ANCA

Ulcerative colitis is an inflammatory bowel disease that in rare cases may develop extraintestinal manifestations. This case report aims to add to the limited clinical data on leukocytoclastic vasculitis and possible ANCA-associated vasculitis as rare cutaneous and rheumatologic extraintestinal manifestations of IBD, particularly in elderly patients. Our case involves a 79-year-old male with a history of mild-moderate ulcerative colitis on oral mesalamine 2.4 g daily and pyoderma gangrenosum who presented with recurrent bilateral polyarthralgia, joint swelling, diffuse lower extremity purpura, acute kidney injury, and scrotal rash. Autoimmune titers were significant for positive ANA and PR3-ANCA. Biopsy of purpuric lesions demonstrated findings suggestive of leukocytoclastic vasculitis. The patient was promptly treated with pulse-dose methylprednisolone for 3 days with rapid improvement of symptoms.

Anti-neutrophil cytoplasmic antibodies-associated vasculitis: a guide and case study

Vasculitis is a relatively rare and poorly understood condition causing inflammation of the blood vessels, which in turn can affect a patient's respiratory and renal systems. In some cases, ocular involvement can cause loss of sight and hearing loss may also be a red flag for vasculitis, which, if not treated early, can cause complete hearing loss. Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) is a group comprising granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis (EGP). AAV is fatal if untreated and as increased risk escalates with age, coupled with a decline in renal function, these are the principal predictors of poor outcome. Vital roles for nursing vasculitis patients lie in managing inflammation and pain, as these distressing symptoms are prevalent in the disease. Because of the multiple complications that can occur with vasculitis, treatment-related information is a high priority for these patients. As nurses are well placed to deliver information, value lies in their role in reducing the negative impacts on treatment regimens and compliance that accompany patients' poor insight into their condition.

Pulmonary granulomas in a patient with positive ANCA and history of tuberculosis: case report

BACKGROUND

Granulomatous polyangiitis (GPA) is a rare multisystem autoimmune disease of unknown aetiology that is pathologically characterised by necrotising vasculitis, tissue necrosis and granulomatous inflammation, typically in the presence of anti-neutrophil cytoplasmic antibodies (ANCA). However infectious diseases may induce high titre ANCA and mimic vasculitis. Tuberculosis may share many clinical features with GPA including fever, arthralgia, granulomatous inflammation and pulmonary lesions and patients.

CASE PRESENTATION

A 39 year old patient was admitted with ocular irritation and redness, arthralgia and multiple new pulmonary lesions. The past medical history was significant for two episodes of tuberculosis previously requiring prolonged treatment. ANCA antibodies were positive and CT showed multiple pulmonary lesions including cavitatory lesions. After extensive investigation, the patient was treated for GPA with high dose immune suppression with good clinical response.

CONCLUSIONS

Here we review the diagnostic considerations between differentiating GPA and tuberculosis in patients from endemic regions. It is recommended that biopsies of lung lesions, sputum microscopy and multidisciplinary team input are sought as part of the workup when these two differentials are being considered.

ANCA-Associated Vasculitis Pathogenesis: A Commentary

PURPOSE OF REVIEW

The ANCA-associated vasculitides are a group of small vessel vasculitides characterized by autoantibodies recognizing the neutrophil cytoplasmic antigens PR3 and MPO. We examine the current clinical and molecular immunology understanding of ANCA-associated vasculitides and discuss the current needs in our understanding of the pathogenic mechanisms of these rare diseases.

RECENT FINDINGS

The majority of efforts to understand the pathogenesis of these diseases have focused on dissecting neutrophil biology because the neutrophil is the primary expressor of ANCA autoantigens. However, a number of important genetic, clinical, and cellular biology observations suggest that attempts to understand the pathogenesis of ANCA vasculitides should move away from emphasis on the role of the neutrophil and instead re-focus on the potential role of other immune cell mediators. Whether or not neutrophils are the key determinant of ANCA-associated vasculitis pathogenesis should be revisited in detail. A neutrophil-centric view of the pathogenesis of these diseases cannot fully account for important genetic, clinical, and cellular biology observations that implicate important and under-appreciated roles for monocytes and T cells. Refocusing on these findings will likely lead to new discovery of novel therapeutic targets and the identification of clinically useful biomarkers for disease activity.

The immunopathology of ANCA-associated vasculitis

The small-vessel vasculitides are a group of disorders characterised by variable patterns of small blood vessel inflammation producing a markedly heterogeneous clinical phenotype. While any vessel in any organ may be involved, distinct but often overlapping sets of clinical features have allowed the description of three subtypes associated with the presence of circulating anti-neutrophil cytoplasmic antibodies (ANCA), namely granulomatosis with polyangiitis (GPA, formerly known as Wegener’s Granulomatosis), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (eGPA, formerly known as Churg-Strauss syndrome). Together, these conditions are called the ANCA-associated vasculitidies (AAV). Both formal nomenclature and classification criteria for the syndromes have changed repeatedly since their description over 100 years ago and may conceivably do so again following recent reports showing distinct genetic associations of patients with detectable ANCA of distinct specificities. ANCA are not only useful in classifying the syndromes but substantial evidence implicates them in driving disease pathogenesis although the mechanism by which they develop and tolerance is broken remains controversial. Advances in our understanding of the pathogenesis of the syndromes have been accompanied by some progress in treatment, although much remains to be done to improve the chronic morbidity associated with the immunosuppression required for disease control.

PR3-ANCA: a promising biomarker for ulcerative colitis with extensive disease

BACKGROUND

We determined if PR3-ANCA is a biomarker that differentiates ulcerative colitis (UC) from Crohn's disease (CrD).

METHODS

A total of 946 sera were tested, including 86 granulomatosis with polyangiitis (GPA) and 491 inflammatory bowel disease (IBD) patients (283 UC and 208 CrD), 264 pathological controls (various diseases) and 105 healthy individuals. All samples were tested for PR3-ANCA by ELISA (QUANTA Flash Lite®, INOVA Diagnostics) and chemiluminescent immunoassays (CIA QUANTA Flash PR3). Conventional anti-neutrophil cytoplasmic antibody (ANCA) indirect immunofluorescence assays (IIF) was performed with NOVA Lite™ (INOVA Diagnostics).

RESULTS

PR3-ANCA by CIA were detected in 31.1% UC vs. 1.9% CrD sera (p=2.2E-16), and by ELISA in 6% UC and 0% CrD (p=0.0003). In GPA patients, PR3-ANCA were detected in 75.6% by CIA and 61.6% by ELISA (p<0.05). PR3-ANCA by CIA were more prevalent in E3-UC compared to E1/2-UC (p<0.05), and in patients with shorter disease duration (p<0.0001). PR3-ANCA showed similar sensitivity, but significantly higher specificity (p<0.05), compared to atypical pANCA by IIF.

CONCLUSION

The novel PR3 CIA may prove helpful in the differentiation of CrD from UC, as well as in the identification of UC patients with more extensive disease.

Initial diagnosis of Wegener's granulomatosis mimicking severe ulcerative colitis: a case report

INTRODUCTION

We describe the case of a woman with an unusual presentation of Wegener's granulomatosis.

CASE PRESENTATION

A 20-year old Caucasian woman presented with the principal feature of a pancolonic, superficial microulceration mimicking severe ulcerative colitis. Our patient was refractory to therapy and had persisting signs of septic shock as well as being at risk of perforation, so we performed a subtotal colectomy and a cholecystectomy due to the incipient necrosis of her gallbladder. Histologic analysis of her colon showed multiple superficial microulcera of the mucosa, lamina propria mucosae and, to a lesser extent, the lamina submucosa. The medium-sized arteries and arterioles of her entire colon, appendix and gallbladder showed acute vasculitic changes with fibrinoid necrosis of the walls and diffuse infiltration with neutrophil granulocytes, accompanied by a strong perivascular histiocyte-rich and partially granulomatous reaction. These findings strongly suggested an autoimmune multisystem disease like Wegener's granulomatosis or microscopic polyangiitis. A diagnosis of Wegener's granulomatosis was confirmed by the results of serologic antibody tests: her cytoplasmic antineutrophil cytoplasmic antibody titer was considerably elevated at 1:2560 specific for subclass proteinase 3 (>200kU/L). After the histopathological diagnosis and serological tests, immunosuppression with high doses of corticosteroids and plasmapheresis was started.

CONCLUSION

In critically ill patients with severe, therapy-refractory ulcerative colitis, Wegener´s granulomatosis should be considered and serologic antibody testing should be performed.

Development and performance evaluation of novel chemiluminescence assays for detection of anti-PR3 and anti-MPO antibodies

BACKGROUND

The detection of anti-proteinase 3 (PR3) and anti-myeloperoxidase (MPO) autoantibodies represents a serological hallmark in the diagnosis of small vessel vasculitis such as granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). We evaluated novel chemiluminescence assays (CIAs) for PR3- and MPO-ANCA detection and investigated their utility for disease activity monitoring.

METHODS

Sera collected from GPA (n=41) and MPA (n=30) patients were tested by QUANTA Lite® PR-3 and MPO ELISAs (INOVA Diagnostics) and by the QUANTA Flash™ PR3 and MPO CIAs (INOVA). Precision and linearity were analyzed following reference guidelines. The recently launched reference sera for PR3-and MPO-ANCA (Centers of Disease Control and prevention, CDC) were used to establish international units for the new assays. Disease activity was determined using the Birmingham Vasculitis Activity Score.

RESULTS

The international standards for PR3-and MPO-ANCA yielded results of 403 CU and 332 CU in the novel CIAs, respectively. The linearity analysis showed linear regression values>0.97 with slopes between 0.96 and 1.04. Total variation obtained from the precision study showed CV% of ≤7.4 for PR3-ANCA and ≤12.8 for MPO-ANCA. Good agreement (Spearman rho ≥ 0.89) was observed between CIA and ELISA. PR3-ANCA determined by CIA, but not by ELISA, was correlated with disease activity. No correlation was found for MPO-ANCA.

CONCLUSION

The novel PR3- and MPO-ANCA CIAs show good precision, linearity and correlation to ELISA. In addition, PR3-ANCA by CIA show correlation with disease activity.

Fulminant Wegener's granulomatosis presenting as epistaxis

The case of a 63-year-old woman who presented to the emergency department with epistaxis and haemodynamic instability is reported. Subsequent investigation showed renal failure and multiple pulmonary nodules. A positive proteinase 3 antineutrophil cytoplasmic antibody test supported the diagnosis of fulminant Wegener's granulomatosis, requiring urgent dialysis, plasma exchange and immunosuppression. This is the first report in the emergency literature of Wegener's granulomatosis presenting as acute epistaxis. Emergency physicians should consider Wegener's granulomatosis in patients with atypical epistaxis. In patients presenting with clinically severe, active disease early proteinase 3 antineutrophil cytoplasmic antibody testing is recommended.

The role of endothelial cell dysfunction in the cardiovascular mortality of RA

Rheumatoid patients present clinically with chronic inflammatory immune arthritis but die of the same cardiovascular (CVS) disease as the normal population. Recent studies emphasize the increased frequency and earlier development of CVS involvement in RA. The mechanisms of this accelerated atherosclerosis are the subject of active research. The hypothesis that rheumatoid vasculitis is a major factor has been pursued through studies in primary systemic vasculitis. These reveal diffuse endothelial dysfunction occurring across a spectrum of vasculitis and involving more than one vascular bed. This may relate to cytokines such as TNF alpha that are both prominent in rheumatoid inflammation and important in the upregulation of endothelium in innate immune responses. Endothelial injury or dysfunction is widely accepted as the initial factor in atheroma. Its occurrence in vasculitis leads us to propose a model for RA where this dysfunction is the essential first step on which other factors, ranging from adverse lipid profiles to specific T-cell subsets, may build accelerated atherogenesis related to the rheumatoid inflammation.