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Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis frequently manifests with involvement of the lungs and kidneys, and it also may affect other anatomic sites. This article presents the patterns of pulmonary injury in which ANCA-associated vasculitis is included in the differential diagnosis, with a discussion of antineutrophil cytoplasmic antibody testing methods. The histologic features of non-vasculitic, potentially-ANCA-associated pulmonary lesions are reviewed briefly as well., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: Anti-neutrophilcytoplasmic autoantibody (ANCA)-associated vasculitis may cause rapid deterioration of renal function, resulting in high prevalence of end-stage renal disease and mortality. The current study investigated factors associated with restoration of renal function and early mortality in patients with severe ANCA-associated glomerulonephritis, i.e. dialysis-dependent at presentation, in a single Chinese cohort., Methods: Eighty-nine Chinese patients with ANCA-associated glomerulonephritis who were on dialysis at the time of diagnosis were included in this study. All these patients received immunosuppressive therapy plus intravenous methylprednisolone, plasma exchange, or both. The predictive value of the clinical and histological parameters for renal and patient outcome was analyzed., Result: On the sixth month, 25 (28.1%) patients achieved dialysis independence, 45 (50.6%) patients progressed to end stage renal disease, and 19 (21.3%) patients died. Nine out of the 19 deaths were therapy-related. Factors independently associated with renal function restoration were percentages of normal glomeruli (P<0.05), extent of tubular atrophy (P<0.05) and extent of interstitial fibrosis (P<0.05) in the renal specimens. Age and pulmonary hemorrhage were independently associated with all-cause death (P=0.003 and P=0.007, respectively) and therapy-related death (P=0.037 and P=0.043, respectively)., Conclusions: Among patients with severe ANCA-associated glomerulonephritis who were dialysis-dependent at presentation, those with a higher percentage of normal glomeruli and less extent of tubular atrophy/interstitial fibrosis have more chance of restoration of renal function. Increased risk for all-cause death and therapy-related death appears to be older age and pulmonary hemorrhage., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Life-threatening haemoptysis may complicate aspergillomas within pre-existing lung cavities. Treatment options have included lung resection, pulmonary or bronchial artery embolisation and antifungal therapy administered either systemically or by endobronchial or percutaneous instillation. We present a case of aspergilloma complicating small vessel vasculitis, and its successful treatment using radiotherapy.

A variety of autoimmune diseases has been associated with thymoma, and thymectomy does not always induce remission of these disorders. This case report describes a 50-year-old man who presented with migratory polyarthritis and an anterior mediastinal mass that proved to be a thymoma. Five months after thymectomy, the patient presented with worsening polyarthritis, hematuria, and azotemia. Based on elevated titers of antineutrophil cytoplasmic antibodies directed against myeloperoxidase and renal biopsy showing crescentic necrotizing glomerulonephritis, microscopic polyangiitis was diagnosed. After remission-induction therapy with prednisone and cyclophosphamide, articular symptoms and renal manifestations resolved. Microscopic polyangiitis was not associated previously with thymoma, and this case broadens the spectrum of autoimmune disorders seen with this tumor. Progressive disease seen after thymectomy in this patient has potential implications regarding the pathophysiological characteristics of microscopic polyangiitis and management of patients with this clinical association.

Background: The common treatment for antineutrophil cytoplasmic autoantibody (ANCA)-associated renal vasculitis is oral cyclophosphamide (CYC)-corticosteroid combination therapy. However, there are serious complications associated with long-term use of CYC. In this study, we investigate the efficacy of a purine synthesis inhibitor, mizoribine, for patients at high risk for relapse., Methods: Our study included 5 patients, 4 patients with myeloperoxidase (MPO)-ANCA-associated renal vasculitis and 1 patient with proteinase 3 (PR3)-ANCA-associated renal vasculitis, who had achieved remission through treatment with methylprednisolone pulse therapy, corticosteroids, and CYC. When their ANCA titers were found to be greater than normal range after remission status, mizoribine treatment was initiated., Results: Median time from initial treatment to first administration of mizoribine was 40.0 months (range, 24 to 51 months). Median follow-up was 13.0 months (range, 6 to 16 months). Before initiation of mizoribine treatment, no patient had experienced relapse and ANCA titers were less than the detectable range in all patients at 3 months before mizoribine administration. When mizoribine administration was started, ANCA titers were elevated in all patients (median MPO-ANCA, 101 ELISA units [EU]; range, 65 to 154 EU; PR3-ANCA, 55 EU), but no new symptoms or signs of relapse were noted. After 2 months of mizoribine treatment, only 1 patient had experienced a relapse; however, ANCA titers had decreased in all other patients and normalized in 3 patients. No adverse effects appeared in any patient., Conclusion: Considering the balance between suppression of disease activity and adverse effects of treatment, mizoribine may be useful for preemptive treatment for patients with ANCA-associated renal vasculitis at high risk for relapse.

Background & Aims: Crohn's disease patients can be characterized by antibody responses against Crohn's disease-related bacterial sequence, Escherichia coli outer membrane porin C, Saccharomyces cerevisiae (oligomannan), and neutrophil nuclear antigens. Our aim was to determine whether expression of antibodies against Crohn's disease-related bacterial sequence and Escherichia coli outer membrane porin C is associated with distinct phenotypic manifestations., Methods: Sera from 303 patients were tested for antibodies to the Crohn's disease-related bacterial sequence (I2), anti-Escherichia coli outer membrane porin C, anti-Saccharomyces cerevisiae, and perinuclear antineutrophil cytoplasmic antibodies and for 3 Crohn's disease-associated variants of the NOD2 gene (R702W, G908R, and 1007fs) and compared with clinical data., Results: Patients expressing I2 were more likely to have fibrostenosing Crohn's disease (64.4% vs. 40.7%; P < 0.001) and to require small bowel surgery (62.2% vs. 37.4%; P < 0.001). Patients with anti-Escherichia coli outer membrane porin C were more likely to have internal perforating disease (50.0% vs. 30.7%; P = 0.001) and to require small bowel surgery (61.4% vs. 44.2%; P = 0.003). Anti-Crohn's disease-related bacterial sequence was independently associated with fibrostenosis (P = 0.027) and small bowel surgery (P = 0.01), whereas anti-Escherichia coli outer membrane porin C was independently associated with internal perforations (P < 0.006). Patients positive for I2, anti-Escherichia coli outer membrane porin C, and anti-Saccharomyces cerevisiae were the most likely to have undergone small bowel surgery (72.0%; odds ratio, 8.6; P < 0.001) compared with patients without reactivity (23.0%). When the presence and magnitude of antibody responses were considered, 90% of patients with small bowel disease who required surgery had high levels of I2, Escherichia coli outer membrane porin C, and oligomannan antibodies, compared with only 18.2% with low-titer responses (P < 0.001)., Conclusions: I2 and anti-Escherichia coli outer membrane porin C are associated with Crohn's disease phenotypes, and patients with the highest level of serum reactivity toward an increasing number of microbiota have the greatest frequency of strictures, internal perforations, and small bowel surgery.

Recurrence of crescentic necrotizing glomerulonephritis after renal transplantation is rare. Successful renal transplantation in patients with antineutrophil cytoplasmic autoantibody (ANCA) glomerulonephritis has been reported. The presence of ANCA at transplantation does not appear to increase the rate of relapse after kidney allografting. Therapy with cyclophosphamide and corticoids usually is effective. We report a case of recurrent perinuclear ANCA crescentic necrotizing glomerulonephritis immediately after renal transplantation that was treated successfully by cyclophosphamide, plasma exchange, and intravenous polyvalent immunoglobulin.

Subarachnoid hemorrhage (SAH) is common in clinical practice. SAH associated with vasculitis is rare. We present an unusually interesting case of SAH from a vertebral artery aneurysm in a young woman found to have advanced renal impairment.

Minocycline is an oral antibiotic widely used for the long-term treatment of acne and rheumatoid arthritis. A few patients develop antineutrophil cytoplasmic antibodies (ANCAs) during minocycline therapy. In this report, the authors describe a case of severe pauci-immune crescentic and necrotizing glomerulonephritis associated with positive cytoplasmic ANCA (C-ANCA) titers and proteinase 3 (PR3) levels after minocycline therapy. Discontinuation of minocycline and initiation of immunosuppressive treatment resulted in improvement of renal function and decline in C-ANCA titers and PR3 levels. A high degree of suspicion, testing for ANCA titers, prompt discontinuation of the drug, and initiation of immunosuppressive treatment are crucial to the diagnosis and treatment of drug-induced ANCA-associated glomerulonephritis.

We report a patient with renal failure secondary to antineutrophil cytoplasmic autoantibody (ANCA)-negative pauci-immune systemic vasculitis who developed rapid recurrence of vasculitis involving skin, eye, and kidney allograft 1 month after cadaveric renal transplant while being maintained on cyclosporine, mycophenolate mofetil, and prednisolone. Despite early institution of aggressive treatment with plasma exchange, the disease remained uncontrolled and resulted in substantial morbidity and subsequent graft failure within 1 year post-transplantation. This case confirms that ANCA-negative vasculitides may recur in transplanted patients taking mycophenolate mofetil. Transplantation is contraindicated when active disease is evident.

A 66-year-old woman developed rapidly progressive renal failure several days after she was diagnosed with non-small cell carcinoma of the lung. Antineutrophil cytoplasmic antibody test performed as an indirect immunofluorescence assay was positive with a perinuclear pattern of staining (pANCA). The patient did not improve with hemodialysis treatment and died on the second day after admission to the hospital. A complete autopsy was performed and showed metastatic adenocarcinoma of the lung and pauci-immune crescentic glomerulonephritis. A literature search showed only 7 previously reported cases of malignant tumors associated with ANCA-positive pauci-immune crescentic glomerulonephritis. The clinicopathologic findings of the current and all previously reported cases and possible relationship between ANCA-positive glomerulonephritis and malignancy are discussed.

Antineutrophil cytoplasmic autoantibodies (ANCA) are commonly associated with a necrotizing and crescentic glomerulonephritis (GN) that is pauci-immune, with few or no glomerular immune complex deposits detectable by immunofluorescence (IF) or electron microscopy (EM). Immunoglobulin A (IgA) nephropathy may also be manifest as a crescentic GN, but it is characterized by mesangial immune complex deposits containing IgA and is rarely associated with myeloperoxidase (MPO)- or proteinase 3 (PR3)-specific ANCA when an enzyme immunoassay is used to detect these antibodies. This report describes six patients with severe crescentic GN with mesangial IgA deposits by IF and mesangial electron-dense deposits by EM in patients with positive ANCA serological test results (four patients, anti-PR3; one patient, anti-MPO; one patient, anti-PR3 and anti-MPO). Patients presented with acute or progressive renal insufficiency, hematuria, proteinuria (nephrotic range in two patients), and hypertension. Three patients had evidence of systemic vasculitis: two patients at initial presentation and one patient later in the clinical course. Renal biopsy specimens showed crescents in greater than 50% of glomeruli in all cases, but only mild, focal and segmental mesangial and endocapillary hypercellularity, more typical of ANCA-associated crescentic GN than of crescentic IgA nephropathy without associated ANCA. Semiquantitative analysis of mesangial and endocapillary cellularity performed on renal biopsy slides from these six patients and from eight ANCA-negative patients with IgA nephropathy and crescents in greater than 50% of glomeruli showed significantly greater hypercellularity in the ANCA-negative cases. Three of five ANCA-positive patients for whom follow-up clinical data were available showed improved renal function after treatment with cyclophosphamide and corticosteroids and have not developed end-stage renal disease 17, 20, and 25 months postbiopsy. The remaining two patients were dialysis dependent at the time of biopsy and have remained so despite treatment with cyclophosphamide and corticosteroids. The findings suggest an overlap syndrome of ANCA-associated crescentic GN and IgA nephropathy that resembles the former both histologically and in its potential to respond to aggressive therapy if detected relatively early in its course.

Renal disease in systemic sclerosis may present in various patterns. A 66-year-old woman with a history of longstanding limited cutaneous systemic sclerosis of the CREST syndrome variant presented with a sudden left foot drop and rapidly progressive renal insufficiency associated with mild proteinuria, a nephritic urine sediment, and a urinary output of 900 mL/d. There was no history of intake of D-penicillamine, and there were no signs of malignant arterial hypertension or microangiopathic hemolytic anemia. Renal histology showed a small vessel vasculitis of the microscopic polyangiitis type. Serologic tests showed a marked increase of antineutrophil cytoplasmic antibodies with a perinuclear pattern and an elevated titer of antimyeloperoxidase antibodies. No clinical or laboratory signs of Sjögren's syndrome were present. This clinical report adds new information to the spectrum of renal disease in systemic sclerosis. It discusses the association between systemic sclerosis and small vessel vasculitis of the microscopic polyangiitis type as well as the possible meaning of serologic markers.

In the glomerulonephritides of systemic lupus erythematosus (SLE), the number of subendothelial deposits, when present, generally corresponds to the degree of light microscopic glomerular hypercellularity; only very rarely are no or few such deposits present in cases of focal (WHO class III) or diffuse (WHO class IV) proliferative lupus nephritis. We have recently encountered five cases of active diffuse proliferative glomerlonephritis with no subendothelial and few or no mesangial deposits and thrombotic microangiopathy (TMA) in four patients with SLE and one patient with lupus-like syndrome. Three of the five patients were tested for circulating lupus anticoagulants or anticardiolipin antibodies, and two were positive. All five patients tested negatively for antineutrophil cytoplasmic antibodies (ANCA). Three patients responded to steroid and cyclophosphamide treatment, although one of them died of acute bacterial bronchopneumonia. One patient was lost to follow-up. We conclude that "pauci-immune" proliferative lupus nephritis is rare and should be treated as proliferative lupus nephritis with a proportionate number of subendothelial deposits. The negative ANCA suggests that these cases do not represent incidental ANCA-associated pauci-immune necrotizing and crescentic glomerulonephritis in patients with SLE. Of particular interest is that, in patients with SLE, if associated with TMA, an active proliferative necrotizing glomerulonephritis may be present even in the absence of significant glomerular immune complex deposition.

The medical history is presented of a 23-year-old man experiencing three episodes of pulmonary-renal syndrome. On the first occasion, a diagnosis of anti-glomerular basement membrane (GBM) disease (with linear deposition of immunoglobulin G [IgG] along the GBM) was made, whereas anti-neutrophil cytoplasmic autoantibodies were also present in serum. On the third occasion, 5 years later, p-ANCA-associated vasculitis (with pauci-immune crescentic glomerulonephritis) was diagnosed, whereas anti-GBM antibodies were absent. The current literature on ANCA-positive anti-GBM disease is briefly reviewed. A substantial proportion (20% to 30%) of patients with histologically and serologically proven anti-GBM nephritis display the presence of ANCA as well. In this group of patients with dual antibodies, clinical and histological findings suggest that ANCA are not merely epiphenomena, but are of pathogenetic importance and might be responsible for an initial vasculitic insult to the kidney with resultant secondary anti-GBM nephritis. The clinical course in our patient lends further support to this concept. Histological demonstration of anti-GBM nephritis followed by ANCA-associated pauci-immune glomerulonephritis in a single patient has not been reported before.

Scleroderma renal crisis is characterized by intimal thickening of the afferent glomerular arterioles resulting in hypertension and fibrinoid necrosis of the capillary tuff. We report a 67-year-old man with long-standing systemic sclerosis who developed normotensive progressive renal failure, proteinuria, and a nephritic urinary sediment with serum myeloperoxidase-antineutrophil cytoplasmatic antibodies (MPO-ANCA). Renal biopsy showed pauci-immune crescentic glomerulonephritis but none of the typical vascular changes of scleroderma renal crisis. Because comparable cases have recently been reported from Japan, normotensive MPO-ANCA-positive crescentic glomerulonephritis may form an entity of progressive renal failure in scleroderma.

We present a case of acute tubulointerstitial nephritis (ATIN) that developed in a 63-year-old man who had been taking cimetidine for treatment of a gastric ulcer. The constellation of clinical, laboratory, and histopathologic findings suggested drug-induced ATIN. Of interest, the patient had antineutrophil cytoplasmic antibody (ANCA) in his sera, reactive with myeloperoxidase, elastase, and lactoferrin. Prominent renal histological features included marked plasmacyte infiltration into the renal interstitium. Withdrawal of cimetidine resulted in complete resolution of renal findings, and the titers of ANCA concomitantly declined. Thus, cimetidine may have played a causative role in the development of ANCA-associated ATIN.

Two patients with rheumatoid arthritis (RA) developed necrotizing crescentic glomerulonephritis with high titers of anti-myeloperoxidase antibodies (MPO) in the absence of overt extrarenal vasculitis. We therefore suggest that in some patients with RA, MPO-ANCA necrotizing glomerulonephritis (GN) may occur as a kidney-limited form of rheumatoid vasculitis, and that RA should be added to the list of diseases potentially associated with necrotizing GN with anti-MPO antibodies. These observations also point out the importance of repeatedly evaluating titers of anti-MPO antibodies in the course of RA, especially if renal impairment or abnormal urinary sediment are present.

Background & Aims: Accurate serological assays are desirable for the diagnosis of inflammatory bowel disease (IBD) types in the pediatric age group. The aim of this study was to test the diagnostic accuracy of modified assays for perinuclear (p) antineutrophil cytoplasmic antibodies (ANCAs) and anti-Saccharomyces cerevisiae antibodies (ASCAs) in patients with pediatric ulcerative colitis (UC) and Crohn's disease (CD) and in those without IBD., Methods: With observers blinded to patients' diagnoses, serum specimens were analyzed for immunoglobulin (Ig) A and IgG ASCAs and ANCAs by enzyme-linked immunosorbent assay. The perinuclear location of ANCAs visualized by indirect immunofluorescence was confirmed by its disappearance after administration of deoxyribonuclease., Results: IgA and IgG ASCA titers were significantly greater and highly specific for CD (95% for either, 100% if both positive). pANCA was 92% specific for UC and absent in all non-IBD controls. The majority of patients with CD positive for pANCA had a UC-like presentation. Disease location, duration, activity, complications, and treatment with immunosuppressive drugs did not have an impact on the ASCA or pANCA assay results. After resection, UC patients remained pANCA positive, in contrast to patients with CD, in whom ASCA titers decreased toward normal values postoperatively., Conclusions: ASCA and pANCA assays are highly disease specific for CD and UC, respectively. These serological tests can assist clinicians in diagnosing and categorizing patients with IBD and may be useful in making therapeutic decisions.

We present the case of a 67-year-old woman with myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA)-positive pauci-immune crescentic necrotizing glomerulonephritis and tubulointerstitial nephritis with renal eosinophilic infiltration and peripheral blood eosinophilia. Staining for eosinophil cationic protein indicated that activated eosinophils were involved in the tubulitis, as well as in the glomerular injury. Marked peripheral blood eosinophilia is uncommon in ANCA-positive crescentic necrotizing glomerulonephritis associated with tubulointerstitial nephritis, except in Churg-Strauss syndrome. However, our patient had no clinical history or signs of asthma, no other signs suggestive of allergic diseases, and no histologic findings of granulomas in the kidney, thus failing to fulfill the criteria for Churg-Strauss syndrome.

Polymorphonuclear neutrophils (PMNs) of patients with active Wegener's granulomatosis and PMN activated in vitro express elastase on their surface as detected by autoantibodies derived from patients with ANCA-positive vasculitis or chronic staphylococcus infections. The PMN-associated elastase was enzymatically active. By affinity-purified autoantibodies to elastase, the enzymatic activity was further enhanced as measured either by a chromogenic peptide or by elastin as substrate. Antibodies to human elastase from mouse or from sheep also enhanced elastase activity, whereas unrelated immunoglobulins had no effect. Taken together, our data indicate that autoantibodies to elastase are not inhibitory but upregulate the elastase activity and thereby might contribute to tissue damage.

Anti-neutrophil cytoplasmic antibodies (ANCAs) of the immunoglobulin (Ig) G isotype are associated with rapidly progressive glomerulonephritis. These have been detected rarely in patients with Henoch-Schönlein purpura (HSP) and have only been previously reported once in a patient with IgA nephropathy (IgAN). In contrast, IgA-ANCAs have been detected in patients with HSP or IgAN, although further verification of this finding by various investigators has yielded conflicting results. We report a case of biopsy-proven IgAN in which the patient developed a rapidly progressive glomerulonephritis and was determined to have ANCAs of both IgA and IgG isotypes. This report suggests an association between fulminant IgAN and ANCA-associated disease and that ANCAs may be underdetected in children with previously diagnosed IgAN. Identification of these antibodies may guide further management of these patients.

A 63-year-old woman developed rapidly progressive glomerulonephritis syndrome with serum myeloperoxidase-anti-neutrophil cytoplasmic antibodies (MPO-ANCA). A renal biopsy showed diffuse crescentic glomerulonephritis. Immunofluorescence and electron microscopic studies showed no significant deposits in the glomeruli. The morphological findings were consistent with pauci-immune type crescentic glomerulonephritis. In addition, the patient had erythropoietin-resistant anemia and subsequent pancytopenia. Bone marrow was normocellular without an excess of blasts. However, multinuclear erythroblasts, hypersegmented neutrophils, and megakaryocytes without platelet formation were observed. Chromosome analysis of the bone marrow showed 47,XX,+7. This is the first case of MPO-ANCA-related crescentic glomerulonephritis in a patient with myelodysplastic syndromes (MDS). A possible relationship between MPO-ANCA and MDS is discussed.

An 18-year-old man with Goodpasture's syndrome developed a recurrent seizure disorder refractory to anticonvulsant therapy spanning a full course of plasmapheresis and cytotoxic therapy. Status epilepticus developed during a taper of cytotoxic agents, with magnetic resonance imaging (MRI) findings consistent with multiple lacunar infarcts. Although the diagnosis of vasculitis was considered, anti-neutrophilic cytoplasmic antibody serology was consistently negative. A meningeal biopsy showed vasculitis, which was successfully treated with the reintroduction of high-dose steroids and cytotoxic agents in conjunction with anticonvulsants. Nearly 1 year later, with Goodpasture's disease in remission, he received a living-related renal transplant from his mother. He is currently leading a normal lifestyle. From an extensive review of the literature, this is the first case of anti-neutrophil cytoplasmic antibody-negative central nervous system (CNS) vasculitis in a patient with Goodpasture's syndrome.

Background & Aims: Antineutrophil cytoplasmic antibodies (ANCAs) have been detected in approximately 60% of sera from patients with ulcerative colitis. The aim of this study was to examine the presence of ANCAs and distribution of ANCA-producing B cells in the lymphoid tissue of T-cell receptor alpha-deficient (TCR-alpha-/-) mice that develop chronic colitis resembling human ulcerative colitis., Methods: Sera from 87 TCR-alpha-/- mice were tested for the presence of ANCAs by enzyme-linked immunosorbent assay against a human neutrophil extract and selected antigens and by immunofluorescence study using human neutrophils. Enzyme-linked immunospot assay was used for detecting ANCA-producing cells from spleen, mesenteric lymph node (MLN), or colon., Results: Approximately 70% of sera from TCR-alpha-/- mice showed reactivity against human neutrophil extracts by enzyme-linked immunosorbent assay. Sixty percent of ANCA-positive sera showed a perinuclear reaction pattern. By enzyme-linked immunospot, ANCA-producing cells were detected in MLN and colon and less often in the spleen of TCR-alpha-/- mice with chronic colitis. The predominant immunoglobulin isotype of these autoantibodies was immunoglobulin A in the colon but not in the MLN and spleen., Conclusions: TCR-alpha-/- mice produce ANCAs. The ANCA (immunoglobulin A isotype)-producing B cells exist primarily in the diseased colonic mucosa of TCR-alpha-/- mice.

Progressive renal failure in patients with scleroderma is a sinister development that is usually attributed to impaired renal blood flow. In some exceptional cases, the underlying pathology is a crescentic glomerulonephritis, which has been associated with positive antineutrophil cytoplasmic antibodies, and in particular antimyeloperoxidase antibodies. The prognosis in such cases has been very poor. We report such a patient whose renal function has improved and stabilized on immunosuppressive therapy.

Background & Aims: Antineutrophil cytoplasmic antibodies (ANCA) have been consistently detected in a subgroup of patients with Crohn's disease (CD). This study was designed to determine whether serum ANCA expression in patients with CD characterizes an identifiable clinical subgroup., Methods: The study population consisted of 69 consecutive patients with an established diagnosis of CD as determined by a combination of characteristic clinical, radiographic, endoscopic, and histopathologic criteria. Sera from the patients were analyzed for the presence of ANCAs using the fixed neutrophil enzyme-linked immunosorbent assay (ELISA) assay. Perinuclear ANCA (pANCA)-positive and cytoplasmic ANCA (cANCA)-positive results by ELISA were confirmed by indirect immunofluorescence staining. Clinical profiles of the ANCA-positive patients with CD were compared with those of patients with CD not expressing ANCA (ANCA-negative)., Results: pANCA-positive patients with CD have endoscopically and/or histopathologically documented left-sided colitis and symptoms of left-sided colonic inflammation, clinically reflected by rectal bleeding and mucus discharge, urgency, and treatment with topical agents. One hundred percent of patients with CD expressing pANCA had "UC-like" features., Conclusions: In patients with CD, serum pANCA expression characterizes a UC-like clinical phenotype. Stratification of CD by serum pANCA provides evidence of heterogeneity within CD and suggests a common intestinal mucosal inflammatory process among a definable subgroup of patients with CD and UC expressing this marker.