The pathology of vasculitis involving the kidney

Systemic vasculitis involving the kidney: the nephropathologist's point of view

Kidneys are often targets of systemic vasculitis (SVs), being affected in many different forms and representing a possible sentinel of an underlying multi-organ condition. Renal biopsy still remains the gold standard for the identification, characterization and classification of these diseases, solving complex differential diagnosis thanks to the combined application of light microscopy (LM), immunofluorescence (IF) and electron microscopy (EM). Due to the progressively increasing complexity of renal vasculitis classification systems (e.g. pauci-immune vs immune complex related forms), a clinico-pathological approach is mandatory and adequate technical and interpretative expertise in nephropathology is required to ensure the best standard of care for our patients. In this complex background, the present review aims at summarising the current knowledge and challenges in the world of renal vasculitis, unveiling the potential role of the introduction of digital pathology in this setting, from the creation of hub-spoke networks to the future application of artificial intelligence (AI) tools to aid in the diagnostic and scoring/classification process.

Acute interstitial nephritis caused by ANCA-associated vasculitis: a case based review

Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) typically manifests as rapidly progressive glomerulonephritis with crescent formation. In this report, we present a local case of myeloperoxidase (MPO)-AAV-associated acute interstitial nephritis (AIN), showing slight pauci-immune glomerulonephritis and positive MPO-ANCA. This case is characterized by foot process effacement of podocytes in the glomerulus, a favorable prognosis, and an absence of crescentic formation. To further understand this condition, we conducted a comprehensive literature search on Google Scholar and PubMed, employing both free text words and MeSH terms related to "AAV and AIN." This search yielded 24 cases, which we analyzed for their clinical features, laboratory findings, renal pathological characteristics, and therapeutic outcomes. AAV-associated interstitial nephritis predominantly affects elderly patients and is often associated with anemia, proteinuria, hematuria, and nonspecific manifestations, including fever, anorexia, fatigue, edema, and weight loss. Most of the cases in our review were MPO-ANCA-positive and exhibited isolated interstitial inflammation. These patients typically presented with relatively lower levels of serum creatinine, 24-h urine protein levels, and MPO-ANCA titers. All patients in our study received immunosuppressive therapy, including glucocorticoids, immunosuppressants, and rituximab, with the majority achieving clinical remission. Isolated AIN in the context of AAV is a rare occurrence, but it displays distinct clinical, laboratory, and pathological features. Patients with this presentation show a positive response to immunosuppressive treatment. Nevertheless, the establishment of definitive therapy guidelines for AAV-associated AIN remains uncertain and necessitates further investigation to develop comprehensive treatment guidelines. AIN, particularly when lacking typical glomerulus lesions, may represent a novel subgroup within MPO-AAV warranting additional research and clinical attention. Key Points • This study contributes valuable scientific insights by highlighting that MPO-AAV-associated interstitial nephritis, even without crescentic formation, can exhibit podocyte foot process effacement and respond well to treatment. • The presence of AIN, independent of crescentic glomerulonephritis, suggests the potential emergence of a new subclass within MPA-AAV. • Notably, some cases of MPO-AAV-associated AIN may present with normal levels of Scr (Table 5, cases 5, 6, and 17). • This observation highlights the importance of considering renal biopsy, diagnosis, and therapy in a timely manner to prevent the development of chronic kidney disease (CKD).

R, Ekhar VR, Shelkar RN, Vedi JN. Limited Granulomatosis With Polyangiitis of Nose and Paranasal Sinuses - a Case Report

Granulomatosis with polyangiitis is a rare disease with involvement of multiple organ system. It classically affects the upper respiratory tract, lower respiratory tract and kidneys. 90% of patients present with upper respiratory diseases like rhinosinusitis, nasal polyposis, nasal septal perforation, serous otitis media, impaired hearing and stridor due to subglottic stenosis. Disease manifests in two forms as limited disease i.e. without renal involvement and generalized disease i.e. with renal involvement. It needs to be differentiated from chronic granulomatous diseases like tuberculosis and delay in the treatment should be prevented. Here we present a case with disease limited to Nose and Paranasal sinuses.

Interstitial nephritis without glomerulonephritis in ANCA-associated vasculitis: a case series and literature review

The typical nephrological presentation of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is rapidly progressive glomerulonephritis. AAV-associated interstitial nephritis without apparent glomerular lesions was rare. We reported three local cases of AAV-associated interstitial nephritis without glomerulonephritis confirmed by renal biopsy. Then, a literature search was conducted in PubMed using free text words and MeSH terms related to "AAV and interstitial nephritis". Fifteen cases were included, and their demographics, clinical manifestations, laboratory data, renal pathological features, and treatment response were summarized. AAV-associated interstitial nephritis usually affects elderly patients. The common symptoms include fever, arthralgias, and edema. These patients were mostly MPO-ANCA positive. Pathological lesions in the kidney showed diffuse infiltration of inflammatory cells, edema, tubulitis, and fibrosis in the interstitial area. Various immunosuppressive treatments, including glucocorticoids, immunosuppressants, and rituximab, were used, and most of the patients achieved clinical remission. AAV-associated interstitial nephritis is rare but shows a characteristic clinical phenotype, serological results, and pathogenic lesions. Immunosuppressive therapy showed good efficacy in these patients.

Tofacitinib-Induced Antineutrophil Cytoplasmic Antibodies (ANCA)-Associated Vasculitis With Crescentic Glomerulonephritis

Antineutrophil cytoplasmic antibodies (ANCA) vasculitis is common after the age of 50 years but it can occur at any age. There is a slight male preponderance and it is more common in Whites than Blacks but the black race confers a worse prognosis. The clinical features of ANCA vasculitis vary considerably. The manifestation of the disease depends on the organs affected, the chronicity of the disease, and how quiescent it is. Non-specific symptoms of malaise, fatigue, fever, and weight loss are common. Crescentic glomerulonephritis with focal necrosis is usually the pathology underlying renal disease. Manifestations of renal disease include hematuria and proteinuria which may progress to renal failure.

We present a case of a 75-year-old female who presented with acute worsening of renal function and nephrotic-range proteinuria with positive testing for p-ANCA after the recent commencement of treatment with tofacitinib. This prompted a suspicion of ANCA-vasculitis. The patient was started on pulse dose steroids and rituximab after kidney biopsy confirmation of ANCA-vasculitis with crescentic glomerulonephritis.

Pulmonary manifestations of large, medium, and variable vessel vasculitis

The hallmark of vasculitis is autoimmune inflammation of blood vessels and surrounding tissues, resulting in an array of constitutional symptoms and organ damage. The lung is commonly targeted in the more familiar ANCA-associated small vessel vasculitidies, but large and medium vessel vasculitides, including Takayasu arteritis, giant cell arteritis, polyarteritis nodosa, Behcet's disease, and necrotizing sarcoid granulomatosis, may also feature prominent pulmonary involvement. Pulmonary manifestations of these conditions include pulmonary arterial aneurysms, pulmonary hypertension, diffuse alveolar hemorrhage, pulmonary nodules, and parenchymal infiltrates. An understanding of the diverse manifestations of vasculitis and a high index of clinical suspicion are essential to avoid delays in disease recognition that may result in permanent or life threatening morbidity. In this review, we outline the general clinical manifestations, pulmonary manifestations, diagnostic workup, imaging findings, and treatment of medium, large, and variable vessel vasculitides.

Renal Involvement in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is the most common cause of rapidly progressive glomerulonephritis. ANCAs play an important role in the pathogenesis and diagnosis of AAV. The classic renal lesion in AAV is a pauci-immune necrotizing and crescentic glomerulonephritis. Treatment is divided into 2 phases: (1) induction of remission to eliminate disease activity and (2) maintenance of remission to prevent disease relapse. AAV patients with end-stage renal disease require modification of immunosuppressive strategies and consideration for kidney transplantation. An improved understanding of disease pathogenesis has led to new treatment strategies being tested in clinical trials.

The management of pediatric renovascular hypertension: a single center experience and review of the literature

INTRODUCTION

Renal artery occlusive disease is poorly characterized in children; treatments include medications, endovascular techniques, and surgery. We aimed to describe the course of renovascular hypertension (RVH), its treatments and outcomes.

METHODS

We performed literature review and retrospective review (1993-2014) of children with renovascular hypertension at our institution. Response to treatment was defined by National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents at most-recent follow-up.

RESULTS

We identified 39 patients with RVH. 54% (n=21) were male, with mean age of 6.93 ± 5.27 years. Most underwent endovascular treatment (n=17), with medication alone (n=12) and surgery (n=10) less commonly utilized. Endovascular treatment resulted in 18% cure, 65% improvement and 18% failure; surgery resulted in 30% cure, 50% improvement and 20% failure. Medication alone resulted in 0% cure, 75% improvement and 25% failure. 24% with endovascular treatment required secondary endovascular intervention; 18% required secondary surgery. 20% of patients who underwent initial surgery required reoperation for re-stenosis. Mean follow-up was 52.2 ± 58.4 months.

CONCLUSIONS

RVH treatment in children includes medications, surgical or endovascular approaches, with all resulting in combined 79% improvement in or cure rates. A multidisciplinary approach and individualized patient management are critical to optimize outcomes.

TYPE OF STUDY

Retrospective comparative study LEVEL OF EVIDENCE: Level III.

Pulmonary vasculitis: diagnosis and endovascular therapy

Pulmonary vasculitides are caused by a heterogeneous group of diseases with different clinical features and etiologies. Radiologic manifestations depend on the predominant type of vessel involved, which are grouped into large, medium, or small-sized vessels. Diagnosing pulmonary vasculitides is a challenging task, and radiologists play an important role in their management by providing supportive evidence for diagnosis and opportunities for minimally invasive therapy. This paper aims to present a practical approach for understanding the vasculitides that can affect the pulmonary vessels and lungs. We will describe and illustrate the main radiologic findings, discussing opportunities for minimally invasive treatment.

Paraneoplastic IgA Vasculitis in an Adult with Lung Adenocarcinoma

A 50-year-old man with lung adenocarcinoma (c-T1aN2M1b) experienced reddish purpura mainly on the lower legs after receiving 12 cycles of second-line chemotherapy with docetaxel. There was tumor enlargement on computed tomography performed to assess the therapeutic response, so paraneoplastic IgA vasculitis was considered. IgA vasculitis was diagnosed based on a biopsy of the skin lesion and histology of an upper gastrointestinal hemorrhagic mucosal erosion. As IgA vasculitis can lead to serious gastrointestinal or systemic complications, IgA vasculitis should be considered as a differential diagnosis for rashes in patients with malignancy.

Small vessel vasculitis of the lung

Interstitial Lung Disease Program, National Jewish Medical and Research Center, Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA The diagnosis and management of SVV remains one of the most challenging clinical scenarios encountered by a clinician. Careful attention to detail and a thorough knowledge of the specific disorders, their therapies, and complications thereof is required to optimally care for these patients. The recent completion of a number of randomized, controlled, multicenter clinical trials has greatly improved our knowledge base and ability to care for vasculitis patient. The next decade holds even more promise.

The Clinicopathologic Spectrum of Rapidly Progressive Glomerulonephritis Based on Glomerular Immune Deposition and Antineutrophil Cytoplasmic Antibody

Rapidly progressive glomerulonephritis presents crescentic glomerulonephritis (CrGN) pathologically. Immune complex (IC)-mediated CrGN is characterized by glomerular IC deposits, whereas pauci-immune CrGN is characterized by presence of antineutrophil cytoplasmic antibody (ANCA) and absence of glomerular IC deposits. CrGN cases presenting both IC deposits and ANCA were common. We retrospectively investigated 91patients with rapidly progressive glomerulonephritis, including 36 patients with idiopathic IC-mediated CrGN and 55 patients with pauci-immune CrGN. On the basis of ANCA and IC deposits, there were 42 patients with ANCA alone (ANCA+IC-), 6 patients with IC deposits alone (ANCA-IC+), 30 patients with both ANCA and IC deposits (ANCA+IC+), and 13 patients with neither ANCA nor IC deposits. The patients with IC-mediated CrGN had more proteinuria, lower estimated glomerular filtration rate (eGFR), higher percentage of cellular crescent formation, and a worse renal outcome compared with those with pauci-immune CrGN. The ANCA+IC+ CrGN patients had lower eGFR level, higher percentage of crescent formation and a tendency of more proteinuria, and worse renal outcome compared with ANCA+IC- CrGN patients, but had no significant differences on the above characteristics compared with ANCA-IC+ CrGN patients. Within a median 7.1 months, 22 patients developed end-stage renal disease. Cox regression revealed the factors including lower eGFR level, more proteinuria, lower platelet level, higher glomerular global sclerosis rate, and glomerular IgG deposits were the independent factors for worse renal outcome. In conclusion, the clinicopathologic spectrum of ANCA+IC+ CrGN was similar with IC-mediated CrGN and glomerular IgG deposition was one of the independent factors for worse renal outcome.

Predictors of renal histopathology in antineutrophil cytoplasmic antibody associated glomerulonephritis

OBJECTIVES

Prompt, aggressive therapy is vital for anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis. In this regard, we aimed to identify predictors of distinct renal histopathological classes at the time of clinical diagnosis.

PATIENTS & METHODS

An inception cohort of patients with biopsy proven ANCA-associated glomerulonephritis was studied retrospectively. Demographics, clinical, laboratory, serological and radiological parameters were analyzed. Patients were classified on the basis of renal histopathology. A risk score was developed for each histopathological class using univariate and stepwise logistic regression analyses.

RESULTS

Variables independently associated with focal class included disease duration up to diagnosis <8 weeks, absence of erythrocyte casts by urine microscopy and eGFR >49 ml/min/1.73 m(2); with crescentic class >40 erythrocytes/hpf, identification of erythrocyte casts in urine, upper respiratory tract involvement and eGFR <49 ml/min/1.73 m(2); with mixed class age >54 years, male gender, and absence of upper respiratory tract involvement. In the presence of these risk factors a predictive risk score for each histopathological classes was calculated: odds ratio, 95% confidence intervals (CI), for focal class (≥2 risk factors, 20.8 (95% CI: 5.1-84.2), p < 0.0001, and 441.0 (95% CI: 16.8-11,590), p = 0.0003 for crescentic class (≥3 risk factors) while the small number of patients in the mixed and sclerotic class precluded any estimates.

CONCLUSION

We propose a predictive algorithm of specific histolopathological classes of ANCA-associated glomerulonephritis, which might provide a crude estimation of the disease activity in the glomeruli at presentation. This tool might assist the clinician in making decisions regarding the level of intensity of inductive immunosuppressive therapy at clinical diagnosis.

Antineutrophil cytoplasmic antibody-negative pauci-immune glomerulonephritis with massive intestinal bleeding

A 61-year-old woman was admitted to hospital because of generalized edema and proteinuria. Her renal function deteriorated rapidly. Serum immunoglobulin and complement levels were within normal ranges. An autoantibody examination showed negative for antinuclear antibody and antineutrophil cytoplasmic antibody. Histologic examination of a renal biopsy specimen revealed that all of the glomeruli had severe crescent formations with no immune deposits. The patient was treated with steroid pulse therapy with cyclophosphamide followed by oral prednisolone. Fifteen days later, she experienced massive recurrent hematochezia. Angiography revealed an active contrast extravasation in a branch of the distal ileal artery. We selectively embolized with a permanent embolic agent. On the 45(th) hospital day, the patient suddenly lost consciousness. Brain computed tomography showed intracerebral hemorrhage. We report a case of antineutrophil cytoplasmic antibody-negative pauci-immune glomerulonephritis with massive intestinal bleeding and cerebral hemorrhage.

The kidneys and ANCA-associated vasculitis: from pathogenesis to diagnosis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are a group of pauci-immune small vessel vasculitides that often affect the kidneys manifesting as rapidly progressive glomerulonephritis. Although the exact pathogenesis of AAV is not fully known, evidence from in vitro, in vivo and clinical studies all point to the involvement of ANCA in the pathogenesis of AAV. In this review, we highlight the contributory roles played by various factors (e.g. genetics, environment, B and T-regulatory cells, toll-like receptors, etc.) in the pathogenesis of AAV. Furthermore, we discuss renal involvement in AAV in terms of clinical features and the various histopathological classification patterns, which are also known to be of prognostic importance. We also present information on useful imaging techniques for localizing kidney and other organ system involvement in AAV, and also on novel laboratory methods and assays useful for rapid and more specific determination of patients' ANCA status. Finally, we demonstrate evidence on novel serum biomarkers that have been shown to correlate with disease activity in AAV.

Giant cell arteritis in a 12-year-old girl presenting with nephrotic syndrome

Giant cell arteritis (GCA) is rare in children. The kidneys are generally spared. We present a case of GCA in a 12-year-old girl with severe headache and tender scalp especially over the right temporal area. The right superficial temporal artery was cord like and nodular and the pulsations were barely felt. Several small tender nodular swellings were felt in the occipital area. She had been previously diagnosed as a case of nephrotic syndrome due to underlying membranoproliferative glomerulonephritis. This report is aimed at drawing attention to this rare form of vasculitis in children aiming at decreasing its morbidities.

Computed tomography angiography in the diagnosis of ANCA-associated small- and medium-vessel vasculitis

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that typically occurs without detectable antineutrophil cytoplasmic antibody. It leads to aneurysm formation by affecting muscular arteries, usually those of medium size but also occasionally those of small size. Kidney involvement is common, leading to reduced glomerular filtration rate, hypertension, rupture of renal arterial aneurysms causing perinephric hematomas, and renal infarctions in those with severe vasculitis. Similar to PAN, microscopic polyangiitis (MPA) leads to aneurysm formation; however, MPA usually is associated with antineutrophil cytoplasmic antibody, and glomerulonephritis is a more common feature of MPA. Although kidney biopsy may show classic vascular changes in both PAN and MPA, this procedure is not without risk of significant bleeding due to aneurysm rupture. We present 2 cases of renal aneurysms that were diagnosed as MPA using computed tomography angiography (CTA), allowing implementation of appropriate immunosuppressive therapy. Follow-up CTA after treatment showed resolution of all previously observed abnormalities. CTA is a useful alternative to kidney biopsy in establishing both the extent of disease in renal aneurysms and allowing for tracking of disease progression and response to therapy.

Endothelium-neutrophil interactions in ANCA-associated diseases

The two salient features of ANCA-associated vasculitis (AAV) are the restricted microvessel localization and the mechanism of inflammatory damage, independent of vascular immune deposits. The microvessel localization of the disease is due to the ANCA antigen accessibility, which is restricted to the membrane of neutrophils engaged in β2-integrin-mediated adhesion, while these antigens are cytoplasmic and inaccessible in resting neutrophils. The inflammatory vascular damage is the consequence of maximal proinflammatory responses of neutrophils, which face cumulative stimulations by TNF-α, β2-integrin engagement, C5a, and ANCA by the FcγRII receptor. This results in the premature intravascular explosive release by adherent neutrophils of all of their available weapons, normally designed to kill IgG-opsonized bacteria after migration in infected tissues.

Crescentic Glomerulonephritis: an update on Pauci-immune and Anti-GBM diseases

Crescentic glomerulonephritis (GN) in a renal biopsy is a widely accepted "critical diagnosis" in Anatomic Pathology practice. Prompt biopsy evaluation and notification of the referring physician is essential to facilitate rapid therapeutic intervention. The differential diagnostic categories of crescentic GN include pauci-immune GN, anti-glomerular basement membrane (GBM) nephritis and immune complex-mediated GN, distinguished from one another by immunofluorescence and electron microscopic study of the renal biopsy. Immune complex-mediated GN is characterized by abundant glomerular deposits and encompasses several diseases including but not limited to lupus nephritis, cryoglobulinemic GN and immunoglobulin A nephropathy. Pauci-immune GN, with paucity of deposits, correlates closely with antineutrophil cytoplasmic antibody disease due to the identifiable circulating pathogenic antineutrophil cytoplasmic antibody in most patients. Recent studies have identified other antibodies in pauci-immune GN and implicated infectious organisms in triggering autoimmunity in a susceptible host by molecular mimicry of host antigens. Anti-GBM nephritis is a rare but potentially life-threatening autoimmune disease with circulating antibodies against GBM epitopes in α3 chain of type IV collagen. It is characterized by a linear immunoglobulin G deposition along GBM on immunofluorescence microscopy. Environmental triggers including infections and solvent exposure seem to change the tertiary structure of the type IV collagen α345 hexamer in GBM, expose neoepitopes, and initiate autoimmunity. Even in light of advances in understanding of pathophysiology and serologic testing, renal biopsy remains the mainstay of diagnosis of crescentic GN.

Therapeutic apheresis for renal disorders

This review summarizes the clinical evidence and practical details for the use of plasmapheresis and other apheresis modalities for each indication in nephrology. Updated information on the molecular biology and immunology of each renal disease is discussed in relation to the rationale for apheresis therapy and its place amid other available treatments. Autoantibody-mediated diseases, such as anti-GBM (anti-glomerular basement membrane) glomerulonephritis (GN), ANCA (antineutrophil cytoplasmic antibody)-related GN and the antibody-mediated type of TTP (thrombotic thrombocytopenic purpura), and alloantibody-mediated diseases such as kidney transplant sensitization and humoral rejection, can be treated by various plasmapheresis methods. These include standard plasmapheresis with a replacement volume, or plasmapheresis with online plasma purification using adsorption columns or secondary filtration. However, it should be noted that the pathogenic molecules implicated in FSGS (focal segmental glomerulosclerosis), myeloma cast nephropathy, and perhaps other diseases are too small to be removed by most online purification methods. A great majority of controlled trials and series on which evidence-based treatment recommendations are made were performed using centrifugal plasmapheresis; it is presumed that membrane-separation plasmapheresis is equally efficacious. For some rarer diseases, such as MPGN (membranoproliferative GN) type 2 with factor H abnormalities or C3Nef (C3 nephritic factor) autoantibodies, there are only a few case reports, but enough scientific understanding to warrant a trial of plasmapheresis in severe cases. Photopheresis, which is effective for cell-mediated rejection in heart and lung transplantation, has not yet found a place in the routine treatment of kidney transplant rejection.

Renal paradoxical embolism in a hypertensive young adult without acute ischemic symptoms

A 22-year-old woman, who often carried heavy books, was admitted for evaluation of hyperreninemic hypertension. Two months prior to admission, she noted leg edema. Radiological examinations revealed bilateral renal infarction with no other abnormal findings. An echocardiography showed a patent foramen ovale (PFO). Hypertension was considered secondary to renal infarction caused by paradoxical embolism through PFO. Antihypertensive and anticoagulant therapy led to improvement of hypertension. In previously reported cases of renal paradoxical embolism, multiorgan involvement was usually observed. Our case is unique in that embolism was confirmed only in the kidneys, and that clinical characteristics of renal embolism were not observed.

Vasculitis in the geriatric population

Vasculitis represents an uncommon but important group of disease entities that may affect older patients. The most common vasculitic disease in humans in giant cell arteritis, a disease process seen almost exclusively in patients older than 50 years in age. Vasculitic disease in geriatric patients presents unique challenges with regard to diagnosis and treatment. A thorough understanding of the vasculitic disease entities that may affect older patients as well as their diagnosis and management is essential in minimizing disease and treatment-related morbidity and mortality.

Secondary hypertension: current diagnosis and treatment

Secondary hypertension affects a small but significant number of the hypertensive population and, unlike primary hypertension, is a potentially curable condition. The determinant for workup is dependent on the index of suspicion elicited during patient examination and treatment. Specific testing is available and must be balanced depending on the risk and cost of the workup and treatment with the benefits obtained if the secondary cause is eliminated. This article reviews common manifestations, workup, and the current treatments of the common causes of secondary hypertension.

Antineutrophil Cytoplasmic Autoantibody–Negative Pauci-immune Crescentic Glomerulonephritis

Pauci-immune crescentic glomerulonephritis (CrGN) is one of the most common causes of rapidly progressive glomerulonephritis. The majority of patients with pauci-immune CrGN had circulating antineutrophil cytoplasmic autoantibody (ANCA). However, patients with ANCA-negative pauci-immune CrGN were not investigated fully. This study aimed to analyze the characteristics of this subgroup of patients. Patients whose pauci-immune CrGN was diagnosed from 1997 to 2006 in one center were studied retrospectively. The criteria of pauci-immune was defined as "the intensity of glomerular immunoglobulins staining by direct immunofluorescence assay in renal sections was negative to 1+ staining on a scale of 0 to 4+." Clinical and pathologic characteristics were compared between patients with and without ANCA. Among the 85 patients with pauci-immune CrGN, 28 (32.9%) were ANCA negative. Compared with the 57 ANCA-positive patients, the ANCA-negative patients were much younger (39.7 +/- 17.0 versus 57.6 +/- 14.0 yr; P < 0.001). The level of urinary protein and the prevalence of nephrotic syndrome were significantly higher in ANCA-negative patients than that in ANCA-positive patients (P < 0.01 and P < 0.001, respectively). However, the prevalence of extrarenal involvement was significantly lower in ANCA-negative patients than that in ANCA-positive patients. The renal survival was poorer in ANCA-negative patients than that in ANCA-positive ones (P < 0.05). ANCA-negative pauci-immune CrGN was not rare and might represent an independent disease entity from ANCA-positive vasculitis.

Bench-to-bedside review: pulmonary-renal syndromes--an update for the intensivist

The term Pulmonary-renal syndrome refers to the combination of diffuse alveolar haemorrhage and rapidly progressive glomerulonephritis. A variety of mechanisms such as those involving antiglomerular basement membrane antibodies, antineutrophil cytoplasm antibodies or immunocomplexes and thrombotic microangiopathy are implicated in the pathogenesis of this syndrome. The underlying pulmonary pathology is small-vessel vasculitis involving arterioles, venules and, frequently, alveolar capillaries. The underlying renal pathology is a form of focal proliferative glomerulonephritis. Immunofluorescence helps to distinguish between antiglomerular basement membrane disease (linear deposition of IgG), lupus and postinfectious glomerulonephritis (granular deposition of immunoglobulin and complement) and necrotizing vasculitis (pauci-immune glomerulonephritis). Patients may present with severe respiratory and/or renal failure and require admission to the intensive care unit. Since the syndrome is characterized by a fulminant course if left untreated, early diagnosis, exclusion of infection, close monitoring of the patient and timely initiation of treatment are crucial for the patient's outcome. Treatment consists of corticosteroids in high doses, and cytotoxic agents coupled with plasma exchange in certain cases. Renal transplantation is the only alternative in end-stage renal disease. Newer immunomodulatory agents such as those causing TNF blockade, B-cell depletion and mycophenolate mofetil could be used in patients with refractory disease.

Classic polyarteritis nodosa presenting rare clinical manifestations in a patient with hemophilia A

A 35-year-old patient with hemophilia A presented with rapidly progressive polyarteritis nodosa (PAN). He had been infected with hepatitis B virus (HBV) by repeated transfusion and was positive for hepatitis B surface antigen but negative for hepatitis B surface antibody. The patient presented symptoms of acute epididymitis followed by emergency admission because of acute appendicitis. On day 7 of admission, he complained of severe back pain, and computerized tomography (CT) showed massive perirenal hematoma. On day 49, mild monoplegia in the left arm suddenly developed, and CT and magnetic resonance imaging revealed multiple cerebral infarctions. Factor VIII replacement therapy was attenuated; however, cerebral infarction was progressive and extended throughout the cerebral hemispheres. He was diagnosed with classic polyarteritis nodosa (cPAN), and pulse methylprednisolone was continued. The patient died of supratentorial herniation, and autopsy revealed that vasculitis associated with intimal thickening was present in the liver, pancreas, intestine, kidneys, and larger-sized cerebral arteries. The development of cPAN appeared to have originated from chronic HBV infection, and this is the first report of cPAN in hemophilia patients. Concomitant hemorrhagic and thrombotic manifestations of cPAN are hardly treatable in patients with coagulation disorders, and the current case may represent a rare transfusion-related complication in hemophilia patients.

Genetic Dissection of Vasculitis, Myeloperoxidase-Specific Antineutrophil Cytoplasmic Autoantibody Production, and Related Traits in Spontaneous Crescentic Glomerulonephritis-Forming/Kinjoh Mice

The spontaneous crescentic glomerulonephritis-forming/Kinjoh (SCG/Kj) mouse is a model of human crescentic glomerulonephritis and vasculitis associated with the production of the myeloperoxidase (MPO)-specific antineutrophil cytoplasmic autoantibody (MPO-ANCA). Although the disease is mediated initially by mutation of the Fas gene (lpr), SCG/Kj mice also have non-Fas predisposing genetic factors. To define these factors, genome-wide quantitative trait locus (QTL) mapping was performed on female (B(6)x SCG/Kj) F(2) intercross mice. Fourteen non-Fas QTLs were identified. QTLs of glomerulonephritis were located on chromosomes 1, 10, 13, 16, and 17, vasculitis on chromosomes 1 and 17, splenomegaly on chromosome 1, hypergammaglobulinemia on chromosomes 1, 2, 4, 6, 7, 11, 13, and 17, antinuclear Ab on chromosomes 1, 8, 10, and 12, and MPO-ANCA production on chromosomes 1 and 10. Significant QTLs derived from SCG/Kj on chromosomes 1, 2, 7, and 13 were designated Scg-1 to Scg-5, respectively, and those derived from B(6) on chromosomes 4, 6, 17, and 10 were designated Sxb-1 to Sxb-4, respectively. Two loci linked to MPO-ANCA production on chromosomes 1 and 10 were designated Man-1 and Man-2 (for MPO-ANCA), respectively. Although both Scg-1 and Scg-2 were on chromosome 1 and shared several functions, it was of interest that aberrant MPO-ANCA production was exclusively controlled by Man-1, the centromeric half region of the Scg-2 chromosomal segment. We also examined the epistatic effects between the lpr mutation and non-Fas susceptibility genes. QTLs are discussed in relation to previously described loci, with emphasis on their candidate genes.

Update in the Diagnosis and Management of Pulmonary Vasculitis

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

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.

Vasculitis in the Geriatric Population

Vasculitis represents an uncommon but important group of disease entities that may affect older patients. The most common systemic vasculitic disease in humans is giant cell arteritis, a disease process seen almost exclusively in patients over the age of 50. Vasculitic disease in geriatric patients presents unique challenges with regard to diagnosis and treatment. A thorough understanding of the vasculitic disease entities that may affect older patients as well as their diagnosis and management is essential in minimizing disease and treatment related morbidity and mortality.

ANCA-negative pauci-immune crescentic glomerulonephritis complicated with recurrent massive gastrointestinal hemorrhage

On April 25, 2003, a 62-year-old Japanese man had been admitted to a hospital because of heavy proteinuria and elevated serum creatinine level, and purpura on the lower extremities. On May 15, 2003, he was referred to our hospital for evaluation and treatment. Serum immunoglobulin and complements were within normal ranges. Immune serology was negative for antinuclear antibody, antiglomerular basement membrane antibody, and antineutrophil cytoplasmic antibodies. Histological examination of a percutaneous renal biopsy specimen revealed that all of the glomeruli had severe crescent formation without deposits of immunoreactants. A diagnosis of antineutrophil cytoplasmic antibody-negative pauci-immune crescentic glomerulonephritis was made. The patient was treated with one cycle of steroid pulse therapy (1000 mg methylprednisolone daily, given on 3 consecutive days), and subsequently with prednisolone (60 mg/day). Despite this treatment, renal failure progressed rapidly and hemodialysis was started 1 month after the acute presentation. On May 30, 2003, he suddenly developed massive hematochezia. A technetium-targeted red-blood-cell scan suggested bleeding in the small intestine. On June 11, he presented with massive melena. A bleeding ulcer was found in the third part of the duodenum, and was treated successfully with endoscopy, using a heater probe. On June 19, he presented with massive hematochezia again. Mesenteric angiography revealed active bleeding from the iliac branch of the superior mesenteric artery. He was treated with continuous intraarterial vasopressin infusion by a catheter seated in the branch artery. The majority of patients with pauci-immune crescentic glomerulonephritis, one of the most common causes of rapidly progressive glomerulonephritis, have glomerular disease as part of a systemic vasculitis. Massive gastrointestinal bleeding, although rare, should be considered one of the serious complications in these patients.

High proteinase 3-anti-neutrophil cytoplasmic antibody (ANCA) level measured by the capture enzyme-linked immunosorbent assay method is associated with decreased patient survival in ANCA-associated vasculitis with renal involvement

Wegener granulomatosis (WG) and microscopic polyangiitis (MP), diseases associated with antineutrophil cytoplasmic antibodies (ANCA), had an extremely poor prognosis before the introduction of cyclophosphamide and corticosteroids for their treatment. However, there is still reduced patient survival, and some studies have documented severe side effects of the immunosuppressants used. This 10-yr follow-up study assessed 117 consecutive patients with WG or MP with biopsy-confirmed renal involvement. The cumulative relative patient survival was lower: 0.664 for women and 0.648 for men. The causes of death (n = 64) were in most cases registered as associated with the vasculitic disease. Analysis of possible predictive factors for patient survival by multiple Cox regression analysis revealed that a very high level of proteinase 3 (PR3)-ANCA measured by the capture ELISA method, a diagnosis of MP, and older age were factors predicting poorer patient survival. High levels of B-thrombocytes at time of diagnosis were associated with a better prognosis. For patients surviving the first year, remission-sustaining therapy with azathioprine for longer than 12 mo was associated with improved patient survival. Thirty-nine patients developed end-stage renal failure. Elevated serum creatinine at time of diagnosis and a very high level of PR3-ANCA by capture ELISA were factors predicting a higher risk for renal failure during follow-up. The epitope on PR3 assessed by capture ELISA needs to be further analyzed and explored: it seemed to implicate poorer patient and renal survival in WG or MP with renal involvement.

Poliangeíte microscópica com hemorragia alveolar difusa

Poliangeíte microscópica é uma forma de vasculite sistêmica de pequenos vasos, associada aos anticorpos anticitoplasma de neutrófilos, que preferencialmente acomete vênulas, capilares e arteríolas, e que pode, entretanto, envolver artérias e veias. Está entre as vasculites sistêmicas primárias de pequenos vasos mais freqüentes, e pode ter apresentação clínica indistinguível da granulomatose de Wegener e da síndrome de Churg-Strauss. Estas vasculites de pequenos vasos são histologicamente semelhantes e podem ser diferenciadas pela presença de granulomas na granulomatose de Wegener, ou de quadro clínico-funcional de asma na síndrome de Churg-Strauss. Relata-se o caso de um paciente do sexo masculino de 66 anos com poliangeíte microscópica com hemorragia alveolar difusa como forma de apresentação clínica, com ênfase no diagnóstico diferencial com outras vasculites pulmonares de pequenos vasos.

Clinicopathologic predictors of death and ESRD in patients with pauci-immune necrotizing glomerulonephritis

BACKGROUND

Pauci-immune necrotizing glomerulonephritis (PING) occurs in various settings and has a very variable prognosis. We investigated whether clinicopathologic findings at the time of renal biopsy may predict major disease outcomes.

METHODS

We evaluated 72 consecutive patients with biopsy-documented PING. Kaplan-Meier curves and Cox models assessed event rates and risk factors for death, end-stage renal disease (ESRD), and death or new ESRD (after the renal biopsy).

RESULTS

During a follow-up of 305 person-years, 11 patients died, 13 patients developed ESRD, and 16 patients died or developed new ESRD. Among patients first seen within 3 months of renal biopsy (incident cases), the 5-year mortality rate was 20%, whereas the death or new ESRD rate was 34%. In univariate analyses, older age, lower creatinine clearance, erythrocyte sedimentation rate, and percentages of abnormal glomeruli, glomeruli with fibrous crescents, and glomeruli with global sclerosis were significant predictors of mortality, whereas antineutrophil cytoplasmic autoantibodies with cytoplasmic staining conferred borderline protection. For ESRD, significant predictors included a greater creatinine level, lower hematocrit, interstitial fibrosis, tubular necrosis, greater C-reactive protein level, and percentages of abnormal glomeruli, glomeruli with extracapillary proliferation, cellular crescents, and global glomerulosclerosis. For death or new ESRD, predictors were fairly similar. Adjusting for baseline creatinine level, the risk for ESRD increased 1.78-fold (95% confidence interval [CI], 1.23 to 2.58) per each 10% increase in global sclerosis and 1.47-fold (95% CI, 1.05 to 2.07) per each 10% increase in glomeruli with cellular crescents.

CONCLUSION

Global glomerulosclerosis and crescents in a renal biopsy are strong predictors of the long-term outcome of PING.