WEGENER'S GRANULOMATOSIS

Antineutrophil cytoplasmic antibody-associated vasculitis

PURPOSE OF REVIEW

This review focuses on latest developments in managing antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV), a systemic autoimmune condition characterized by inflammation and necrosis of small blood vessels due to circulating autoantibodies that target neutrophilic granules.

RECENT FINDINGS

Our understanding of AAV pathogenesis has evolved in the past decades highlighting the central pathogenic roles of autoantibodies and complement activation. In parallel, the appreciation for glucocorticoid toxicity has led the research on crucial steroid-sparing therapeutic alternatives. Complement inhibitors (like avacopan) that have emerged are associated with better preservation of kidney function in AAV patients with severe kidney impairment. The role of plasma-exchange (PLEX) was revisited in updated guidelines that recommended its potential use in the context of diffuse alveolar hemorrhage associated hypoxia and severe kidney involvement, particularly with a serum creatinine level above 3.4 mg/dl. The ANCA Kidney Risk Score risk prediction and Glucocorticoid Toxicity Index score aid in identifying high-risk patients and individualizing management plans.

SUMMARY

Kidney involvement in AAV requires prompt diagnosis and initiation of immunosuppression to prevent irreversible nephron loss. Newer therapeutic targets are on the horizon and offer hope for personalized treatment strategies.

Evolution of Therapy for ANCA-Associated Vasculitis with Kidney Involvement

ANCA-associated vasculitis (AAV) belongs to a group of small vessel systemic vasculitides characterized by granulomatous and neutrophilic inflammation of various tissues. Patients often have circulating autoantibodies targeting neutrophilic antigens. Although AAV was once associated with severe end-organ damage and extremely high mortality rates, the use of glucocorticoids and cyclophosphamide led to a paradigm change in its treatment. Over the past 20 years, significant progress in understanding the immunopathogenesis of AAV has enabled development of targeted immunotherapies, providing a much better prognosis for patients. This review describes the evolution of treatment of AAV, particularly for patients with kidney involvement.

Oral and Lower Extremity Ulcers as the Initial Presentation of Granulomatosis with Polyangiitis

Background

Granulomatosis with polyangiitis (GPA) is a small vessel vasculitis characterized by lung and kidney involvement. It is typically a disease of white females and has a poor prognosis with the average life expectancy of 5 months for a patient without treatment. Oral and skin ulcers are considered to be rare presentations.

Case

A 39-year-old black male presented to the hospital with oral and skin ulcers and was diagnosed with GPA based on the biopsies of both cutaneous lesions and kidney. He was started on rituximab with minimal improvement. Later he was admitted to the ICU and had plasmapheresis, and he gradually improved and was discharged home 8 days after admission.

Conclusion

GPA is an aggressive vascular disorder resulting in possible organ system damage and failure. The role of the sickle cell trait in this patient is undefined, but this combination of gender, race, and presenting symptoms in GPA is extremely unusual.

Hemiretinal Vein Occlusion in Wegener's Granulomatosis

PURPOSE

To report a case of hemiretinal vein occlusion in a patient with Wegener's granulomatosis.

RESULTS

Retinal vein occlusion may occur in patients with Wegener's granulomatosis even in the absence of active inflammation affecting the retinal venules.

CONCLUSIONS

Wegener's granulomatosis should be considered in the diagnostic workup of young patients with major retinal vascular occlusion and concurrent history of pulmonary and/or renal disease.

An Unusual Presentation of Limited Granulomatosis with Polyangiitis Involving Vagina and Urethra

Granulomatosis with polyangiitis (GPA) is a systemic necrotizing granulomatosis vasculitis characterized by predilection to affect small- and medium-sized blood vessels and commonly affects the upper and lower respiratory tract and kidneys in most cases. Genital involvement is reported in <1% of cases in large cohorts and nearly all cases have been in the setting of multisystemic disease or during the course of the disease in patients already diagnosed as GPA. A case is presented of uncommon limited urogenital GPA in a 66-year-old woman with an irregular mass occupying urethra and vagina. The patient showed a good response after Corticoids and Methotrexate.

Prostatitis and acute urinary retention as first manifestations of Wegnener's granulomatosis

OBJECTIVES

We present a case of prostatitis with acute urinary retention as a rare initial manifestation of Wegener' Granulomatosis.

METHODS

The case was a 48-year-old male with symptoms of prostatitis over ten days. The patient presented urinary retention, with partial response to antibiotic treatment. High levels of cytoplasmic antineutrophil cytoplasmic antibody and a prostatic biopsy were compatible with Wegener' Granulomatosis.

RESULTS

After starting treatment with glucocorticoids and cyclophosphamide, a significant improvement to the point of disappearance of symptoms was observed. At 3 months pulmonary and upper airway symptoms began, requiring higher doses of cyclophosphamide to control symptoms.

CONCLUSIONS

Wegener's Granulomatosis is a multisystem entity whose presentation as prostatitis with urinary retention is rare.

Refractory pituitary granulomatosis with polyangiitis (Wegener's) treated with rituximab

OBJECTIVE

Granulomatosis with polyangiitis (GPA), also known as Wegener's granulomatosis, is an autoimmune disease characterized by inflammation of blood vessels most often seen in the upper respiratory tract, lungs, kidneys, and skin. Central nervous system (CNS) involvement of GPA is rare, particularly in the pituitary, and can be difficult to treat.

METHODS

Case report.

RESULTS

We present a 30-year-old woman with pituitary and ocular GPA, whose unusually recalcitrant disease led to the development of pan-hypopituitarism and near-total vision loss. After failing multiple systemic immunosuppressants, she was ultimately treated with the novel immunomodulatory agent rituximab together with pulse corticosteroids, which achieved a gratifying response.

CONCLUSION

Pituitary and optic chiasm involvement is a rare complication of GPA. We believe this case illustrates the complexity of management of pituitary GPA and provides insight into the potential utility of the biologic agent rituximab in this disease.

Pulmonary vasculitis as the first manifestation of rheumatoid arthritis

In this report, we describe a 61-year-old man that presented with isolated pulmonary vasculitis and a positive anti-cyclic citrullinated peptide (CCP) antibody. Within a few months, the patient developed the symmetric polyarthritis consistent with rheumatoid arthritis (RA). Because the anti-CCP antibody is highly specific for RA and vasculitis is a known association of RA, we suspect the pulmonary vasculitis in this patient was the first manifestation of underlying RA. This case extends on previous reports that have shown that lung disease may predate the development of articular RA and that anti-CCP positivity and lung disease may represent a pre-RA phenotype. To our knowledge, this is the first case report of pulmonary vasculitis as the first manifestation of RA.

Current status of the treatment of microscopic polyangiitis and granulomatosis with polyangiitis in Japan

BACKGROUND

This study aimed to describe the epidemiologic characteristics of microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) in Japan.

METHODS

We used the database of the Ministry of Health, Labour and Welfare (MHLW) from 2006 to 2008, and analyzed data from 938 patients (MPA = 697, GPA = 241) who fulfilled the MHLW diagnostic criteria and had registered within a year after onset.

RESULTS

The mean ages of the MPA and GPA patients were 69.4 ± 0.4 and 58.4 ± 1.1 years, respectively. Renal (86.9 %), chest (73.7 %), and nervous system (45.2 %) symptoms were common in MPA patients. Ear, nose, and throat (86.7 %), chest (78.0 %), and renal (60.6 %) symptoms were frequently observed in GPA patients. The concomitant use of cyclophosphamide (CY) with corticosteroids was observed in 22.2 % of the MPA patients and 58.5 % of the GPA patients. In multivariate analysis, the concomitant use of CY was associated with a younger age and pulmonary hemorrhage in MPA patients, and the avoidance of CY was associated with nervous system symptoms and rapidly progressive glomerulonephritis in GPA patients. Plasma exchanges were inducted in 5.2 % of the MPA patients and 4.1 % of the GPA patients. The addition of plasma exchange was associated with elevation of the serum creatinine level in patients with both MPA and GPA.

CONCLUSION

A dominance of MPA and a reduced frequency of renal involvement in GPA patients may be significant features of the Japanese population. Clinical practice relating to MPA and GPA in Japan can be characterized as follows: CY is used less commonly, and plasma exchange is employed for patients with deteriorated renal function.

Skin involvement in ANCA-associated vasculitis

The skin is a common target organ in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Skin lesions may present as the initial manifestation or as the associated cutaneous manifestations in ANCA-associated vasculitis. Visually assessing the cutaneous manifestations and performing a biopsy of skin lesions to facilitate histopathologic confirmation are highly valuable diagnostically. Vasculitis (which affects dermal small vessels and subcutaneous muscular vessels) and nonvasculitic inflammation cause various types of skin lesions. The coexistence of different levels of vasculitis and nonvasculitis can occur in one or in several lesions or on different occasions. These puzzling clinical and histopathologic features may be closely related to the disease activity. Understanding the complicated clinical and histopathologic spectrum of skin lesions will contribute to the early diagnosis of ANCA-associated vasculitis with cutaneous complications.

Wegener's Granulomatosis: Strawberry Gums of the Oral Cavity

Wegener's Granulomatosis is a rare and potentially life-threatening vasculitic disease of unknown origin. The diagnosis of Wegener's Granulomatosis is made on the basis of clinical presentation, positivity for serum c-ANCA and histologic examination of the lesions. This report details a case of limited Wegener's Granulomatosis with hyperplastic gingivitis lesions presenting as an initial manifestation of Wegener's Granulomatosis. The resemblance of the affected gums to over-ripe strawberries is pathognomonic of this condition and is thus highlighted. Because of the rarity of Wegener's Granulomatosis presenting initially in the oral cavity, clinicians should be alerted to the characteristic appearance of “strawberry gingivitis”.

Pediatric Wegener's granulomatosis with oral ulcers and progressive periodontitis: a case report

Wegener's granulomatosis (WG) is a rare multisystem disorder. Although it can occur at any age, it is rarely observed in children. Oral manifestations, which are present in fewer than 10% of patients, include oral ulceration, nonhealing extraction sockets, and the most common oral lesion, hyperplastic gingivitis, which is known as "strawberry gingivitis." We report the unusual case of a 6-year-old boy with WG who presented with atypical oral manifestations, including severe progressive periodontitis accompanied by oral ulcers, before the development of systemic symptoms. Although WG is rare, this case emphasizes the importance of considering the diagnosis in those who present with progressive and atypical oral disease, as prompt treatment of the systemic illness can significantly improve outcome.

Evaluation of smell and taste in patients with Wegener's granulomatosis

Although a reduced olfactory/gustatory function affects patients in all parts of life, this problem has not received much attention in Wegener's granulomatosis (WG). The aim of this study was to assess the smell/taste function of WG patients. Demographic data of 16 WG patients (9 males, 7 females) were obtained. They all subjectively assessed their taste/smell function on visual analogue scale. Olfactory/gustatory functions of the patients were tested with 'Sniffin' Sticks and 'Taste' strips, respectively. The results were then compared with those from sex and age-matched control group (n = 16) and normative data. WG patients subjectively assessed their olfactory (p = 0.03) and gustatory (p = 0.02) function to be lower than control group. All the olfactory scores (odour identification, odour discrimination and threshold) in both genders were significantly below the scores in the control group. WG patients were hyposmic. For taste (total taste score, as well as scores for the qualities sweet, sour, salty and bitter), WG patients did not significantly differ from controls and were normogeusic. However, the gustatory scores showed the tendency of reduction as compared to the control group. In conclusion, WG patients truly suffer from olfactory/taste dysfunction, but this is worse with olfaction. It is, therefore, imperative that physicians should make their patients to be aware of these sensory dysfunctions and educate them on methods to cope with it for better quality of life.

[Wegener granulomatosis - otologic, nasal, tracheobronchial and pulmonary involvement]

Wegener granulomatosis is a rare systemic idiopathic disease characterized by involvement of small vessels - medium and small arteries, venules, arterioles and ocasionally large arteries. This disease has predilection for the upper and lower respiratory tract and the kidney, with granulomatous inflamation and necrosis. Clinical manifestations and organ involvement of the disease vary widely. Early diagnosis and treatment may lead to a full recovery. Without treatment, Wegener's granulomatosis can be fatal. The authors present a case of a 33 year-old female, with severe disease, but with good outcome, after adequate diagnosis and treatment.

Lingual infarction in Wegener's Granulomatosis: a case report and review of the literature

Wegener's granulomatosis (WG) is a multi-system disease, characterised by the triad of necrotising granulomata affecting the upper and lower respiratory tracts, disseminated vasculitis and glomerulonephritis. Oral lesions are associated with up to 50% of cases, although are rare as a presenting feature. The most common oral lesions associated with WG are ulceration and strawberry gingivitis. We review the literature regarding oral manifestations of WG and present a case of lingual infarction, an extremely rare oral lesion associated with WG, in a severe, rapidly progressive and ultimately fatal form of the disease.

Laryngopharyngeal reflux mimicking limited wegener granulomatosis

We present a case of subglottic stenosis (SGS) in a young patient with positive ANCA but a wrong diagnosis of Wegener granulomatosis (WG). Instead, she was diagnosed as having laryngopharyngeal reflux (LPR). Pitfalls of ANCA testing in this scenario, the route to diagnosis of LPR and the contribution of this entity to subglottic stenosis (SGS) in WG are discussed. Caution when interpreting ANCA results is mandatory to avoid improper management.

Orbital Inflammatory Disease

OBJECTIVES

To familiarize rheumatologists and internists with the signs, symptoms, and management of orbital inflammatory disease (OID).

METHODS

A comprehensive literature review related to OID was performed and reported from the perspectives of rheumatology, ophthalmology, and radiology.

RESULTS

OID is a general term encompassing inflammatory diseases that affect some or all of the structures contained within the orbit external to the globe. Orbital involvement as a part of the initial symptom complex is not uncommon for systemic diseases such as Graves' disease, Wegener's granulomatosis, and sarcoidosis. The management of these and other causes of OID, such as idiopathic orbital inflammation (formerly known as "orbital pseudotumor"), orbital myositis, and Tolosa-Hunt syndrome frequently involves systemic immunosuppression. Before immunosuppression is considered, however, infectious and malignant causes of inflammation must be ruled out.

DISCUSSION

Rheumatologists should be familiar with the differential diagnosis of OID and often need to assist colleagues in ophthalmology and internal medicine with the management of this group of diseases.

Relapsing Splenic Vein Thrombosis Associated With Antiphospholipid Antibodies in a Patient With Wegener Granulomatosis

Relapsing splenic vein thrombosis, a very rare complication of Wegener granulomatosis (WG), is described in a female patient. Positive antiphospholipid antibodies found in this case are a rare occurrence in primary vasculitis, especially in WG. This probably caused or accentuated an effect of the WG on the splenic vein. Treatment of such patients with antiphospholipid syndrome and WG must include anticoagulation and immunosuppression and, as noted in this patient, the splenic vein thrombosis and other antiphospholipid syndrome and WG can resolve quickly.

Eosinophil activation in Wegener's granulomatosis: a harbinger of disease progression?

PURPOSE

To investigate the relation between eosinophil activation in tissue from patients with an active, limited form of Wegener's granulomatosis (WG) affecting the eye and subsequent systemic disease activity.

METHODS

Analysis of ocular specimens obtained from 10 patients was performed. Sections were probed with antibodies to assess the presence of major basic protein (MBP) and eosinophil cationic protein (ECP).

RESULTS

Four of the 10 specimens demonstrated the presence of MBP and ECP. WG progressed to the complete form in two of these patients, who received no or inadequate treatment. The other two, treated with cyclophosphamide for one year, did not progress to the complete form of WG during observation after therapy.

CONCLUSIONS

Activated eosinophils in sclera or conjunctiva of patients with ocular limited WG may predict progression to complete WG.

Wegener's granulomatosis of the breast

Wegener's granulomatosis is a multisystem disorder characterized by necrotizing granulomatous inflammation and vasculitis of small vessels and can affect any organ system. The most common sites of involvement are upper and lower respiratory tracts, and kidneys. Breast involvement is unusual and very rare. We report a case of breast Wegener's granulomatosis in a 32-year-old woman who presented with pulmonary lesions and palpable masses in the left breast. Mammography showed multiple, sharply delineated nodules without microcalcifications. Ultrasonography revealed multiple hypoechoic solid lesions, some of them with anechoic areas of necrosis. Computed tomography showed multiple nodules. Histopathology of excision biopsy specimens of breast lesions revealed necrotizing granulomatous material consistent with Wegener's granulomatosis. Twenty reports of breast involvement in this rare disease were found in the literature; however, the respective ultrasonographic and computed tomography findings have not hitherto been described.

Uncommon causes of cough: ACCP evidence-based clinical practice guidelines

OBJECTIVES

To describe the uncommon causes of cough.

DESIGN/METHODOLOGY

An English language literature search by MEDLINE citations from 1975 through 2004 was used to identify publications on uncommon pulmonary and nonpulmonary disorders in which cough was present as the major or presenting symptom in >50% of those persons affected by the uncommon diseases.

RESULTS

A substantial number of uncommon or rare pulmonary and nonpulmonary disorders were identified. The uncommon occurrence of these diseases made it difficult to develop a meaningful evidence-based guideline to the diagnosis and therapy of many of the uncommon causes of cough. As cough was the major or presenting symptom, it was usually initially attributed to common respiratory diseases (eg, asthma or bronchitis). As a result, a substantial time lag existed from the onset of cough to the diagnosis of the etiologic entity. Diagnostic tests limited to the respiratory system did not always provide clues to the diagnosis of uncommon causes of cough.

CONCLUSIONS

Cough is the major or presenting symptom in many uncommon pulmonary and nonpulmonary disorders. A strong index of suspicion is essential to consider and diagnose the uncommon causes of cough. The diagnosis and management of cough in patients with uncommon causes of cough is dependent on the underlying etiology.

Fatal endocarditis in Wegener's granulomatosis: mitral valve involvement and an intracardiac mass

Reported here is a 39-year-old man with Wegener's granulomatosis who had died due to endocarditis during his follow up. The concomitance of these two pathologies is discussed in the light of the pertinent literature.

The Clinical Spectrum of Primary Renal Vasculitis

BACKGROUND AND OBJECTIVES

The vasculitides are potentially severe and often difficult to diagnose syndromes. Many forms of vasculitis may involve the kidneys. This review will focus on the clinical and histopathological aspects of renal involvement in the systemic vasculitides.

METHODS

We searched the MEDLINE database using as key terms the MeSH terms and textwords for different forms of vasculitis and for renal involvement, creating a database of more than 2200 relevant references.

RESULTS

The frequency of renal involvement in vasculitis varies among different syndromes. It is more frequent in Wegener's granulomatosis and microscopic polyarteritis, while it is uncommon to rare in other forms of vasculitis such as Behçet's disease and relapsing polychondritis. The vessels affected include the renal artery in Takayasu arteritis, medium-size renal parenchymal artery in classic polyarteritis nodosa, and glomerular involvement in Wegener's granulomatosis and microscopic polyarteritis. The clinical expression of renal vasculitis depends on the size of the affected vessels and includes renovascular hypertension, isolated nonnephrotic proteinuria, interstitial nephritis, and glomerulonephritis, which can be rapidly progressive. Diagnosis is established by a combination of history, clinical manifestations, laboratory findings (eg, urine sediment, urine protein, antineutrophil cytoplasmic antibodies), imaging techniques (renal angiography, especially when there is a suspicion of medium-to-large vessel disease, and chest radiograph), and finally, renal biopsy. Prognosis varies from unfavorable in the rapidly progressive glomerulonephritis of microscopic polyarteritis, which can lead to renal failure, chronic dialysis, and renal transplantation, to benign, as in the case of Henoch Schonlein purpura, in which the majority of patients recover.

CONCLUSIONS

The manifestations and prognosis of renal vasculitis range widely. Renal involvement greatly influences prognosis and dictates the need for early and prompt immunosuppressive therapy. Thus, the clinician should be alert for the timely diagnosis and treatment of renal vasculitis.

Estudio clínico-biológico y radiológico de la granulomatosis de Wegener en un hospital universitario

Wegener's granulomatosis is a rare systemic vasculitis that fundamentally affects the kidney and respiratory tract. Although the histological findings are very characteristic, they do not occur in all cases, which makes diagnosis difficult.

METHODS

The main clinical, biological and radiological characteristics of 13 cases of Wegener's granulomatosis diagnosed in a university hospital of the center of Spain are collected in this present paper.

RESULTS

The majority of the patients were men in their 50's. Fever and general syndrome were usual presentations of the disease. Upper respiratory tract (10 cases) and lung involvement (9), followed by renal involvement (8), were the most common. Alveolar infiltrates and bilateral nodules were the most common findings in the X-ray and thoracic CT scan, although the latter permits a greater definition of the lesions. Measurement of antibodies against cytoplasma of the neutrophils (ANCA) was positive in 8 patients (6 cANCA and 2 pANCA). Renal biopsy was used most for the histologic diagnosis, where focal and segmental glomerulonephritis was the most common finding. The majority of the patients received steroids plus cyclophosphamide as induction treatment.

CONCLUSIONS

Wegener's disease is a rare systemic vasculitis. The existence of hematuria or respiratory tract involvement in a patient with fever suggests the diagnosis. Conducting a CT scan and ANCAs measurement are useful tools for its diagnosis, since the histology is not definitive.

Cerebral demyelination in Wegener's granulomatosis

A 38-year-old woman with a history of a granulomatous lesion of the nose, developed blurred vision, ataxic gait, and spastic tetraparesis. The presence of demyelination on the brain MRI led to the diagnosis of cerebral demyelination associated with Wegener's granulomatosis. Pulse cyclophosphamide administration resulted in some clinical of improvement of her condition. Demyelinating lesions seen in Wegener's have been ascribed to multiple sclerosis, but in this case, they are much more reminiscent of disseminated encephalomyelitis (DEM). The immunological challenge of the underlying disease, may, in the genetically susceptible person, presumably trigger the appearance of MS lesions. Wegener's granulomatosis must be considered in the differential diagnosis of MS.

Treatment of interstitial lung disease in children

The treatment of interstitial lung disease in children depends on the nature of the underlying pathology. In approximately 50% of cases a specific aetiology can be found such as: chronic viral infection, an auto-immune process, sarcoidosis or alveolar proteinosis. In the remainder, the process is idiopathic and the pathological findings are based on the descriptive morphological features seen in the diagnostic lung biopsy. If a specific cause is found then targeted treatment with antivirals, steroids or other immunosuppressive agents is available. Alveolar proteinosis can be treated by bronchial lavage and GM-CSF. Idiopathic cases are treated primarily with intravenous pulsed methylprednisolone or oral prednisolone backed up hydroxychloroquine. Other immunosuppressive agents such as azathioprine, methotrexate or ciclosporin have been used successfully in individual patients. The prognosis is very variable and includes no response to any therapy, partial response with chronic long term morbidity, to virtually complete recovery. The overall mortality rate is 15%. There are no controlled therapeutic trials available because of the rarity of these conditions in childhood. Unlike in adult practice, no correlation has as yet been demonstrated between the initial pattern of chest x-ray change or the degree of pathological change on the lung biopsy and the clinical outcome. The recurrence rate within families is 1 in 8.

Oculorenal manifestations in systemic autoimmune diseases

Vasculitides form a heterogeneous group of diseases characterized by blood-vessel inflammation and necrosis. They have a wide spectrum of manifestations because of the involvement of arteries and other vessels of various sizes and locations. Early diagnosis and prompt treatment may decrease the morbidity and mortality associated with these disorders. Examination of the eye and kidney should be performed routinely in those diseases. This article reviews the major types of oculorenal manifestations in systemic autoimmune diseases.

Antineutrophil cytoplasmic antibodies and associated diseases: a review of the clinical and laboratory features

There have been a number of recent advances in this field. First, the "International Consensus Statement on Testing and Reporting of Antineutrophil Cytoplasmic Antibodies (ANCA)" has been developed to optimize ANCA testing. It requires that all sera are tested by indirect immunofluorescent (IIF) examination of normal peripheral blood neutrophils and, where there is positive fluorescence, in enzyme-linked immunosorbent assays (ELISAs) for antibodies against both proteinase 3 (PR3) and myeloperoxidase (MPO). Testing will be further improved when international standards and common ELISA units are available. Second, new diagnostic criteria for the small vessel vasculitides that take into account ANCA-positivity and target antigen specificity as well as histologic features are currently being produced. Third, we understand that the complications associated with treatment of the ANCA-associated vasculitides are often more hazardous than the underlying disease, and regimens that use effective but less toxic agents are being evaluated. The factors associated with increased risk of relapse, however, remain incompletely understood. Finally, ANCA with specificities other than PR3 and MPO are present in many nonvasculitic autoimmune diseases. Their clinical significance is still largely unclear, and some of the target antigens are present in other cells as well as neutrophils and thus are not strictly "ANCA."