Positive Myeloperoxidase Anti-neutrophil Cytoplasmic Antibody Research Articles

Latent class analysis of chest CT abnormalities to define subphenotypes in patients with MPO-ANCA-positive microscopic polyangiitis

BackgroundPatients with microscopic polyangiitis (MPA) and positive myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) may present with various abnormalities in chest computed tomography (CT). This study aimed to identify subphenotypes using latent class analysis (LCA) and to explore the relationship between the subphenotypes and clinical patterns, as well as compare the clinical characteristics of these subphenotypes in patients with MPO-ANCA-positive MPA (MPO-MPA). MethodsThe study identified subphenotypes using LCA based on chest CT findings in 178 patients with MPO-MPA and pulmonary involvement from June 2014 to August 2022. ResultsLCA identified 27 participants (15.2%) in class 1, 43 (24.1%) in class 2, 35 (19.7%) in class 3, and 73 (41.0%) in class 4. Class 1 was characterized by prominent inflammatory exudation, class 2 by fibrosis and architectural distortion, class 3 by predominantly bronchiectasis, and class 4 by lesions mixed with inflammation and fibrosis. Class 1 had the highest level of extrapulmonary disease activity, with 77.8% of patients experiencing diffuse alveolar hemorrhage. Class 2 had the lowest level of extrapulmonary disease activity, with 41.9% of patients showing usual interstitial pneumonia. Class 3 patients were more likely to have complications involving the ear, nose, and throat, as well as pulmonary infections before treatment, and they exhibited the best outcomes. The characteristics and outcomes of class 4 were intermediate among the four classes. ConclusionsThese findings suggest that bronchiectasis may represent a unique pattern of pulmonary involvement in MPO-MPA, highlighting the importance of screening for bronchiectasis in MPO-MPA and identifying optimal management strategies.

Successful treatment for life threatening recurrent non-traumatic rectus sheath hematoma in a case with microscopic polyangiitis with rapidly progressive glomerulonephritis.

A 68-year-old woman was admitted to our hospital because of a rapid progression of renal dysfunction with positive myeloperoxidase antineutrophil cytoplasmic antibody and was diagnosed with rapidly progressive glomerulonephritis associated with microscopic polyangiitis (MPA). Severe right rectus sheath hematoma (RSH) bleeding from the inferior epigastric artery developed after starting hemodialysis, which required 4 transarterial embolizations due to recurrent bleeding. After additional treatment with methylprednisolone pulse therapy and rituximab, no rebleeding occurred. Although the giant hematoma reached the pelvis, it shrank spontaneously without any intervention. Nontraumatic RSH should therefore be considered when treating patients with multiple risk factors.

Severe Pulmonary Embolism, Thrombosis of Lower Extremity, Unexpected Mild Renal Disorder in MPO-ANCAAssociated Vasculitis: A Case Report

Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) associated vasculitis is an autoimmune disease usually with severe multiple dysfunction syndrome, especially prominent acute renal failure. A 65-year-old woman was admitted with progressive dyspnoea for six months and fever, sputum with blood, pain of the lower extremities and intermittent claudication for two days, indicating multiple organ involvement (respiratory system, blood vessels). The renal involvement was relatively mild, presenting with microscopic haematuria. The chest computed tomography demonstrated multiple pulmonary embolisms. Ultrasound and computed tomography angiography for the lower extremity vessels showed venous and arterial thrombosis. Exclusion of other diseases that can cause multiple organ damage and thrombosis, the positive perinuclear ANCA and MPO-ANCA strongly support the diagnosis of MPO-ANAC-associated vasculitis. The patient's physical condition has been greatly improved by treatment with corticosteroids and anticoagulation.

Clinicopathological features of IgG4-related kidney disease .

To explore the clinicopathological features of IgG4-related kidney disease (IgG4-RKD) in Chinese patients. We retrospectively analyzed the clinicopathological features of 7 patients with IgG4-RKD and reviewed relevant literature. There were 7 patients (4 males and 3 females) aged 41-78 years (median age: 57.1 years), with a mean affliction of 2.6 organs per patient. All 7 patients had elevated serum IgG4 levels, and most of them had acute or chronic renal insufficiency. Two patients had positive myeloperoxidase-antineutrophil cytoplasmic antibodies (MPO-ANCA), and another 2 patients had positive serum antinuclear antibodies (ANA). All 7 patients had tubulointerstitial nephritis (TIN) with IgG4+ plasma cell infiltration, 3 patients also had glomerular lesions, 2 patients had ANCA-associated glomerulonephritis (ANCA-GN), and the remaining patient had membranous nephropathy (MN). All these patients were treated with glucocorticoids, and 3 of them were given cyclophosphamide simultaneously. Six patients achieved remission and had improved renal function, while 1 patient was on maintenance dialysis. IgG4-RKD should be diagnosed by combining the clinical data and renal pathological changes, and it should be differentiated from a variety of diseases. Although ANCA-associated vasculitis (AAV) and IgG4-related disease are distinguishable in most cases, coexistence of ANCA-GN and IgG4-RKD should be considered in some special cases.

Pre-existing chronic interstitial pneumonia is a poor prognostic factor of Goodpasture\u2019s syndrome: a case report and review of the literature

BackgroundGoodpasture’s syndrome is a rare disease that is characterized by rapidly progressive glomerulonephritis and diffuse alveolar hemorrhage.Case presentationA 71-year-old Japanese man who had chronic interstitial pneumonia was diagnosed as having Goodpasture’s syndrome. Both anti-glomerular basement membrane antibody and myeloperoxidase anti-neutrophil cytoplasmic antibody were increased. Despite intensive treatments, including mechanical ventilation, he died from respiratory failure. Pathological findings at autopsy showed rapidly progressive glomerulonephritis in his kidneys, diffuse alveolar hemorrhage, hyaline membranes, and fibroblastic foci in his lungs. The cause of death was diagnosed as respiratory failure as a result of diffuse alveolar damage induced by a combination of diffuse alveolar hemorrhage and exacerbation of interstitial pneumonia.ConclusionsWe report a case of Goodpasture’s syndrome complicated with pre-existing chronic interstitial pneumonia and positive myeloperoxidase anti-neutrophil cytoplasmic antibody. We reviewed six similar cases reported in the literature and concluded that Goodpasture’s syndrome with pre-existing interstitial pneumonia and myeloperoxidase anti-neutrophil cytoplasmic antibody is related to a poor prognosis.

A Case Report Describing a Rare Presentation of Simultaneous Occurrence of MPO-ANCA-Associated Vasculitis and Rheumatoid Arthritis.

Background. Renal-limited myeloperoxidase vasculitis with simultaneous rheumatoid arthritis is reported as a rare occurrence. Review of literature suggests that most patients had a diagnosis of rheumatoid arthritis for several years prior to presenting with renal failure from myeloperoxidase vasculitis. Case Presentation. A 58-year-old Caucasian male presented to the hospital experiencing malaise, fevers, decreased oral intake, nausea, and vomiting for one week duration. His past medical history consisted of newly diagnosed but untreated rheumatoid arthritis, hypertension, and non-insulin-dependent diabetes mellitus. He was found to have acute renal failure, proteinuria, and hypoglycemia. Standard therapy, including intravenous fluids, did not improve his acute renal failure. A vasculitis workup resulted in a positive myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA). Renal biopsy revealed crescentic glomerulonephritis (GN) pauci-immune type, suggestive of MPO-ANCA-associated vasculitis (MPO-AAV). Treatment consisted of prednisone, cyclophosphamide, and seven cycles of plasmapheresis, in addition to hemodialysis for uremia. Upon discharge, he received hemodialysis for another week and continued treatment with cyclophosphamide and prednisone. Conclusion. Patients with longstanding rheumatoid arthritis may develop renal failure due to nonsteroidal anti-inflammatory medication use and AA type amyloidosis; however, necrotizing glomerulonephritis with crescent formation has been rarely reported. This stresses the importance of early recognition and swift initiation of treatment.

Comparative investigation of respiratory tract involvement in granulomatosis with polyangiitis between PR3-ANCA positive and MPO-ANCA positive cases: a retrospective cohort study.

BackgroundThe clinical characteristics of myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) positive granulomatosis with polyangiitis (GPA) remain unclear, as does the difference between MPO-ANCA positive GPA and proteinase 3 (PR3)-ANCA positive GPA, especially with regard to the details of respiratory tract involvement. We investigated the differences in clinical, radiological, and histopathological features between PR3-ANCA positive GPA and MPO-ANCA positive GPA.MethodsWe retrospectively reviewed 16 patients who were newly diagnosed with GPA between December 2000 and July 2014. One patient, who was positive for both PR3-ANCA and MPO-ANCA, was excluded. Our review was based on the European Medicine Agency (EMA) algorithm.ResultsFifty-six percent of GPA patients were positive for PR3-ANCA, 38 % for MPO-ANCA, and the remaining 6 % for both. The MPO-ANCA positive group included a greater number of females (67 %). There were no statistically significant differences in laboratory data, symptoms and signs, Birmingham Vasculitis Activity Score, or CT findings between the two groups. As for upper respiratory tract involvement, the most common manifestation was paranasal sinusitis, whereas lung nodules were most common as the lower respiratory tract involvement in both groups. Although the combination therapy with prednisone and cyclophosphamide was the most common initial treatment in both groups, the relapse rate in MPO-ANCA positive cases was lower than that of PR3-ANCA positive cases (17 % and 56 %, respectively).ConclusionA high prevalence of MPO-ANCA positive GPA was noted. No significant differences in clinico-radiological findings were observed except for the prevalence of relapse between the PR3-ANCA positive cases and MPO-ANCA positive cases, suggesting that the type of ANCA may be of little help in the diagnosis of GPA. Examination for granulomatous findings in the respiratory tract is important, even in MPO-ANCA positive cases. There is a need to accumulate more cases and conduct a further investigation in the future.

Mediastinal Fibrosis and Positive Antineutrophil Cytoplasmic Antibodies: Coincidence or Common Etiology?

Retroperitoneal fibrosis (RPF) with positive antineutrophil cytoplasmic antibodies (ANCA) has been reported in several cases. We herein present the case of a 52-year-old woman who was diagnosed with mediastinal fibrosis (MF) on a thoracoscopic surgical biopsy. The patient had positive myeloperoxidase ANCA and thereafter developed crescentic glomerulonephritis, which was considered to be a form of ANCA-related nephritis. Both the MF and crescentic glomerulonephritis favorably responded to immunosuppressive therapy. These findings suggest a common pathogenesis of these disorders involving ANCA positivity, as reported in patients with RPF.

Multiple cranial nerve palsy revealing hypertrophic pachymeningitis with positive myeloperoxidase-antineutrophil cytoplasmic antibody

Pachymeningitis is a progressive disease resulting in a diffuse thickening of dura mater due to inflammation, tumor or autoimmune diseases, but most cases are idiopathic. Here, we report the case of a 60-year old man who had a progressive sensorineural hearing loss, visual disturbance and others cranial nerve involvement with an accompanying headache over several months. Brain magnetic resonance imaging showed diffusely thickened dura mater, highly enhanced after gadolinium administration, which was consistent with pachymeningitis. It was assumed to be related to autoimmune pathogenesis on the basis of elevated serum myeloperoxidase-antineutrophil cytoplasmic antibody titers. After empirical steroid and cyclophosphamide therapy, the neurological problems were partially improved. Therefore, in the case of atypical sensorineural hearing loss accompanied by cranial nerve palsy or headache, pachymeningitis should be considered in the differential diagnosis.

Hypertrophic Pachymeningitis in an Individual with Microscopic Polyangiitis

Hypertrophic pachymeningitis (HPM) is a rare disorder that thickens the dura mater, occurring in association with trauma, infection, neoplasm, and autoimmune disease.1 In autoimmune diseases, HPM may occur with various conditions, including myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA)-positive vasculitis.1, 2 A case of visual loss due to HPM during a course of MPO-ANCA-positive microscopic polyangiitis (MPA) is presented. A 70-year-old woman who had been diagnosed with renal biopsy-proven MPA was admitted to the hospital because of frontal headache and right visual impairment. She had no history of bronchial asthma, sinusitis, or eosinophilia. On admission, right uncorrected vision decreased from 20/28.5 to 20/500. Laboratory examination revealed white blood cell count of 11,940/μL, red blood cells 402 × 104/μL, platelets 25.1 × 104/μL, aspartate aminotransferase 16U/mL, alanine aminotransferase 20 U/mL, lactate dehydrogenase 242 U/mL, alkaline phosphatase 133 U/mL, gamma-glutamyl transpeptidase 26 U/mL, serum creatinine 1.2 mg/dL, C-reactive protein 1.1 mg/mL, erythrocyte sedimentation rate 56 mm/h, CH50 45 U/mL, C3 147.0 U/mL, C4 37.0 U/mL. MPO-ANCA was 23 U/mL (normal range <10 U/mL), whereas proteinase-3-ANCA was negative. Examination of cerebrospinal fluid indicated lymphocytic pleocytosis without evidence of infectious organisms, including syphilis, tuberculosis, and fungi. Axial T1-weighted gadolinium-enhanced cranial magnetic resonance imaging (MRI) showed diffuse thickening and enhancement of dura mater around the frontal cranial dura, consistent with HPM (Figure 1A). The woman was diagnosed with HPM associated with MPO-ANCA-positive MPA. She was treated with methylprednisolone 500 mg/d for 3 days, followed by prednisolone 50 mg/d. Headache improved, and visual activity improved to 20/200, and MPO-ANCA titers returned to a normal range. MRI findings of dura mater after the treatment also improved (Figure 1B). HPM is pathologically characterized by infiltrations of lymphocytes and plasma cells into the dura mater. HPM may occur in association with underlying disorders such as infection, malignancy, and autoimmune disease.1 Most recently, immunoglobulin G4–related disease was reported to induce HPM.3 In cases of autoimmune diseases, granulomatosis with polyangiitis (Wegener's) is the autoimmune disease most likely to cause HPM. Even in cases with granulomatosis with polyangiitis (Wegener's) that is usually a positive for proteinase 3-ANCA, MPO-ANCA is frequently positive when complicated with HPM.4, 5 Thus, a positive MPO-ANCA is reported to be closely associated with HPM.5 MPA, a disease that is most closely associated with MPO-ANCA, has rarely been reported in a setting of HPM, only three cases having been reported of MPA associated with HPM.6-8 An additional case of MPA complicating HPM is reported herein. This case also had visual disturbance. Central nervous system involvement is infrequent in MPA. Optic neuropathy was reported to occur in individuals with HPM.9 HPM should also be a concern in individuals with visual disturbance with MPA. ANCA-associated vasculitides, including MPA, are increasingly recognized in elderly adults, with a median age of 65 in one study,10 but HPM in individauls with MPA had been rarely reported. The oldest reported case of HPM with MPA was in an 81-year-old individual.8 The 70-year-old woman reported herein is the second oldest case of MPA complicated with HPM. Because the incidence of MPA is greatest in elderly adults, HPM should be considered when neurological manifestations, including visual disturbance, occur during a course of MPA. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: Tsuda, Shinoda, Hounoki: case management. Taki: initial assessment and management of the case, study concept and design, preparation of manuscript. Tobe: literature review. Sponsor's Role: None.

AB0478 Anca associated vasculitis presenting with anterior ischemic optic neuropathy

BackgroundAnterior Ischemic Optic Neuritis (AION) is caused by arteritic and non arteritic factors. Giant Cell Arteritis is one of the well-recognised causes of arteritic AION. AION is a rare but...

A case of myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA)-associated glomerulonephritis and concurrent membranous nephropathy

BackgroundMyeloperoxidase anti-neutrophil cytoplasmic antibody-associated glomerulonephritis (MPO-ANCA-GN) and concurrent membranous nephropathy (MN) are very rare combination. Their causal relationship has been suggested, but not determined.Case presentationA 73-years-old male with 5-year history of proteinuria underwent an operation for his sigmoid colon cancer. Seven months later, he was referred to a nephrology division due to an exacerbating renal function and hypoalbuminemia. Laboratory examination revealed positive MPO-ANCA in the serum. A renal biopsy revealed a necrotizing extracapillary proliferative glomerulonephritis with crescents, demonstrating MPO-ANCA-GN. Whereas, immunofluorescent staining documented granular deposition of immumoglobulin (Ig) G and C3 along the capillary wall and electron microscopy showed subepithelial deposits in the glomerular basement membrane demonstrating MN. Immunofluorescent staining of IgG subclass showed positive IgG1, IgG2, negative IgG3 and weak positive IgG4 suggested the possibility of malignancy-associated MN.ConclusionCombination of MPO-ANCA-GN and MN are rare. Although the causal relationship has been suggested in some cases, we should consider all the possibilities including idiopathic MN and secondary MN associated with malignancy, drug use or infection.

Incidence of myeloperoxidase anti-neutrophil cytoplasmic antibody positivity and microscopic polyangitis in the course of idiopathic pulmonary fibrosis

Pulmonary fibrosis is a manifestation of microscopic polyangitis (MPA), and often precedes the detection of MPA. The prevalence and sequence of myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) and MPA in patients initially diagnosed with idiopathic pulmonary fibrosis (IPF) have not been precisely elucidated. We enrolled 61 consecutive patients with IPF and measured the MPO-ANCA titers at initial presentation and during the follow-up period. Clinical, radiologic and histologic features of MPO-ANCA-positive cases were examined. Of 61 patients, 3 (4.9%) had positive MPO-ANCA titers at the initial presentation of IPF. During the disease course, MPO-ANCA-positive conversion occurred in 6 patients and the prevalence of ANCA increased to 14.8%. Among the nine patients positive for MPO-ANCA, two patients developed MPA during follow-up. Histologic features of MPO-ANCA-positive pulmonary fibrosis were compatible with the usual interstitial pneumonia pattern in which alveolar hemorrhage and capillaritis were not observed. The patients with MPO-ANCA-positive conversion showed increased percentages of bronchoalveolar lavage eosinophils and more frequent complication of pulmonary emphysema compared to those with MPO-ANCA-negative IPF. The findings of the present study demonstrated that patients with an initial diagnosis of IPF occasionally acquire MPO-ANCA, which develops to MPA during the disease course of IPF. The presence of pulmonary eosinophilia and low attenuation areas on computed tomography scans might be predictive of MPO-ANCA positive conversion.

Microscopic polyangiitis presenting with peripheral and central neurological manifestations

Although peripheral neuropathy is a common complication of microscopic angiitis, manifestations involving the muscle and the central nervous system have been rarely reported. We describe a 48-year-old man who rapidly developed a clinical picture of mononeuritis multiplex. A month after the appearance of the primary symptoms, he became comatose and had left hemiplegia in relation with a massive cerebral haematoma. Laboratory data revealed signs of inflammation, glomerular dysfunction with microhaematuria, and positive myeloperoxidase-antineutrophil cytoplasmic antibodies. The neuromuscular biopsy disclosed a small-vessel vasculitis, consisting with microscopic angiitis, associated with myositis and extensive axonal loss. The patient had surgical evacuation of the haematoma and received immunosuppressive therapy with good outcome. Thus, microscopic angiitis should be considered as a differential diagnosis in cases of myositis and intracerebral haemorrhage.

Churg–Strauss syndrome complicated by central retinal artery occlusion: case report and a review of the literature

A 68-year-old man was admitted with rapid visual loss. Churg-Strauss syndrome (CSS) was diagnosed, based upon the symptoms of asthma, eosinophilia, interstitial pneumonitis, and positive myeloperoxidase-anti neutrophil cytoplasmic antibody (MPO-ANCA). Light reflexes were absent and vision was completely lost in both eyes. Bilateral central retinal artery occlusion (CRAO) was observed by fluorescence angiography. Steroid pulse along with an anticoagulant improved the visual acuity to light perception and hand motion. CSS-associated CRAO should be considered when acute visual loss occurs.

Development of myeloperoxidase-antineutrophil cytoplasmic antibody-associated renal vasculitis in a patient receiving treatment with anti-tumor necrosis factor-α

We report on a 33-year-old woman who presented with positive myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) during rheumatoid arthritis treatment with infliximab. She had a history of worsening arthralgia, and urinalysis showed the new occurrence of hematuria and proteinuria. Renal biopsy showed necrotizing crescentic glomerulonephritis. Immunosuppressive therapy and discontinuation of the infliximab therapy alleviated her arthralgia and improved the urinalysis results. We report this rare case in which an anti-tumor necrosis factor-α (TNF-α) agent for ANCA-associated systemic vasculitis was studied.

Arteritic anterior ischemic optic neuropathy with positive myeloperoxidase antineutrophil cytoplasmic antibody

Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) is related to smallvessel vasculitis. There have been some reports of optic nerve involvements with increased values of MPO-ANCA. We report two cases of anterior ischemic optic neuropathy (AION) in which ANCA-associated vasculitis was suspected to be responsible for the pathogenesis. A 66-year-old man and a 72-year-old man had ocular symptoms of AION in both eyes with positive MPO-ANCA. Both patients showed high erythrocyte sedimentation rate, C-reactive protein, and MPOANCA values at first. Temporal artery biopsies were negative for temporal arteritis, whereas small-vessel vasculitis was found only in the latter patient. Visual dysfunctions remained unchanged after steroid pulse therapy, although laboratory data returned to normal levels after the treatment. Fluorescein angiography revealed selective occlusion of capillaries, arterioles, and precapillaries in the retina and choroid as well as in the optic disc. The identical characteristics of the angiographic findings of both eyes in the two cases indicated that the obliteration of small vessels in the intraocular arterial system was closely related to MPO-ANCA-associated vasculitis.

A Long-term Follow-up of Serum Myeloperoxidase Antineutrophil Cytoplasmic Antibodies (MPO-ANCA) in Patients with Graves Disease Treated with Propylthiouracil

Propylthiouracil (PTU) is known to induce myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) in patients with Graves disease (GD). Previously, we showed that serum MPO-ANCA were frequently seen in patients with GD treated with PTU. In this study, we analyzed 13 patients with positive MPO-ANCA examining a long-term clinical consequence of these patients as well as antibody titers during 5.6 +/- 3.0 years. PTU therapy was continued in 8 patients and discontinued in 5 patients. Antibody titers decreased in 7 of 8 patients who discontinued PTU therapy but remained positive in 5 patients 5 years after PTU withdrawal. The initial MPO-ANCA levels were significantly higher in those antibody titers remained positive for longer than 5 years (n=5) than in those titers turned to be negative within 5 years after PTU withdrawal (n=3) (203 +/- 256 EU and 22 +/- 2 EU, respectively, P=0.04), but there were no significant differences in age, gender, duration of PTU therapy or dosage of PTU. Among 5 patients who continued PTU therapy, 2 patients with initially low MPO-ANCA titers turned to having negative antibody. No patients had new symptoms or signs of vasculitis throughout the follow-up periods. The long-term follow-up study suggests that higher MPO-ANCA levels remain positive for years after PTU withdrawal but are rarely associated with vasculitis.

Pulmonary fibrosis in myeloperoxidase antineutrophil cytoplasmic antibody-associated vasculitides.

The association of pulmonary fibrosis (PF) with myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitides has not been well documented. The aim of this study was to assess the clinicopathological characteristics of PF in patients who tested positive for MPO-ANCA. In this study, 31 patients (17 males and 14 females; mean age, 69 years) diagnosed as having PF with positive MPO-ANCA levels ranging from 10 to 840 EU with a mean of 112.5 EU, were evaluated clinicopathologically. Among 31 patients with PF, 22 had underlying systemic diseases such as collagen vascular diseases, while nine had unknown aetiology. Evidence of glomerulonephritis was demonstrated in 14 patients. The clinical features were a history of dry cough and/or fine crackles in all 31 patients. Chest CT scans showed honeycombing in the lung bases in 26 patients. The histopathological features of the diseased lung tissues in all 11 autopsied cases were compatible with the usual interstitial pneumonia (UIP) pattern. Vasculitis was confirmed in bronchial arteries and/or pulmonary arterioles in five patients. The mortality was as high as 13 of the 31 patients. The causes of death were: deterioration of PF in five (two of whom were associated with pulmonary haemorrhage), lung cancer in two, pneumonia in four, and digestive tract bleeding in two. The survival rates in PF with MPO-ANCA-negative collagen vascular diseases, cryptogenic fibrosing alveolitis (CFA), and PF with positive MPO-ANCA, were compared. The 5-year survival rate in PF with positive MPO-ANCA was worse than in PF with MPO-ANCA-negative collagen vascular diseases and was the same for CFA. Although there was no correlation between MPO-ANCA titres and the activity of PF, this study demonstrated that the presence of positive MPO-ANCA was an unfavorable prognostic factor in patients with PF.