Single-organ Vasculitis Research Articles

Systemic vasculitis: a modern view on the problem

The aim of the study was to summarize the literature data on various types of systemic vasculitis, their mechanisms of development, diagnostic possibilities, and to describe a clinical case. Systemic vasculitis is a group of diseases with heterogeneous etiology, which involve vessels of different calibers, predominantly small and/or medium, manifesting as multi-organ dysfunction, difficult to treat, and with a poor prognosis. Currently, the following types are distinguished: large vessel vasculitis; medium vessel vasculitis; small vessel vasculitis; variable vessel vasculitis; single-organ vasculitis; vasculitis associated with systemic diseases; vasculitis associated with specific etiology. In the clinic of internal medicine, kidney involvement (glomeruloand tubulopathies, renal insufficiency), skin (ulcerative-necrotic and trophic changes), lungs (interstitial involvement, respiratory insufficiency, recurrent pneumonias), and central nervous system (acute ischemic events, thromboses, polyneuropathies, cognitive disorders, gait disturbances), heart (myocarditis with heart failure) are most commonly encountered. Systemic vasculitis most often manifests in winter and spring periods. Hemorrhagic vasculitis and Kawasaki disease are most commonly seen among children and young adults. In the post-COVID era, systemic vasculitis has been detected more frequently. The study presents the results of personal observation of a patient suffering from infectious-toxic systemic vasculitis.

Development and organization of Tabriz University of Medical Sciences Vasculitis Registry: TUOMS-VR

This manuscript describes the establishment and initial results of a patient-driven registry in Tabriz, Iran to collect demographic, clinical, and paraclinical data, treatment and outcomes of patients with vasculitis. The Tabriz University of Medical Sciences Vasculitis Registry (TUOMS-VR), a patient-driven, prospective and web-based disease registry system, is conducted at the Connective Tissue Diseases Research Center, TUOMS located in Tabriz, Iran. The primary objective of this registry is to comprehensively document prospective data of patients diagnosed with systemic or single-organ vasculitis according to the Chapel Hill Consensus Conference nomenclature and definitions. To date, the registry has successfully enrolled 743 patients. The gender distribution within this existing cohort is balanced, with 50.5% male and 49.5% female participants. The most frequently diagnosed condition was Behcet’s disease, representing 56.5% of cases. Polymyalgia rheumatica also emerged as a notable diagnosis, accounting for 13.7% of cases. By providing a comprehensive and prospective documentation of vasculitis cases, the TUOMS-VR aims to enhance vasculitis patients care and outcomes.

Single organ vasculitis: Description based on Chapel Hill Conference Consensus 2012 and a case report

Single organ vasculitis: Description based on Chapel Hill Conference Consensus 2012 and a case report

De Novo Vasculitis after COVID-19 Vaccination.

The coronavirus disease 2019 (COVID-19) pandemic continues to spread around the world. Vaccinations have been administered globally and have been proven to be safe and effective. However, vasculitis has been reported as an adverse event occurring after COVID-19 vaccination. In this review, we analyzed the literature to identify original articles that reported on patients who developed vasculitis following COVID-19 vaccination and summarized their clinical manifestations. PubMed and Web of Knowledge were searched to identify relevant studies. A total of 27 patients who developed vasculitis following COVID-19 vaccination were identified from 21 studies. The involved organs included the skin and kidney. The main clinical features of patients whose skin was affected were papules, maculopapular rashes, and plaques. Most of the patients exhibited small vessel vasculitis and single-organ vasculitis; these were resolved within one month. Patients whose kidneys were affected exhibited vasculitis, including anti-neutrophil cytoplasmic antibody glomerulonephritis and IgA nephritis. Most patients were treated with corticosteroid, rituximab, and cyclophosphamide, and one patient needed hemodialysis. The renal function of most patients was improved or recovered, but one patient needed maintenance dialysis. Vasculitis was rarely reported after COVID-19 vaccine administration. It often manifested as cutaneous small-vessel vasculitis or glomerulonephritis. Notably, when a patient demonstrates hematuria, proteinuria, and acute kidney injury after COVID-19 vaccination, there is a possibility that the patient could have developed vasculitis. Skin-related problems were quickly resolved, while kidney-related problems may progress to chronic kidney disease.

Significance of anti-transcobalamin receptor antibodies in cutaneous arteritis revealed by proteome-wide autoantibody screening

Cutaneous arteritis (CA) is a single-organ vasculitis that exclusively affects the small to medium-sized arteries of the skin. Diagnosis depends on a histological investigation with skin biopsy, which could be burdensome for both patients and clinicians. Moreover, the pathogenesis of CA remains unstudied, and treatment has not yet been established. Herein, we applied our proteome-wide autoantibody screening method to explore autoantibodies in the serum of CA patients. As a result, anti-transcobalamin receptor (TCblR) antibodies (Abs) were specifically detected in 24% of CA patients. Patients with positive anti-TCblR Abs were spared from peripheral neuropathy compared to those with negative anti-TCblR Abs, showing characteristics as CA confined to the skin. In addition, we revealed that anti-TCblR Abs trigger the autocrine loop of interleukin-6 mediated by tripartite motif-containing protein 21 in human endothelial cells and induce periarterial inflammation in murine skin. Furthermore, we demonstrated that methylcobalamin, a ligand of TCblR, ameliorates inflammation caused by anti-TCblR Abs both in vitro and in vivo. Collectively, our investigation unveils the pathologic significance of anti-TCblR Abs in CA and their potential as a diagnostic marker and a pathophysiology-oriented therapeutic target.

Cutaneous Small Vessel Vasculitis: A Practical Guide to Diagnosis and Management.

Cutaneous vasculitis may be a cutaneous manifestation of systemic vasculitis, a skin-limited variant of systemic vasculitis, or a type of single-organ vasculitis limited to the skin. Careful evaluation is necessary to distinguish these possibilities, differentiate skin-limited from systemic disease, and identify important underlying conditions, if present. Appropriate management depends on disease type and severity. In the case of cutaneous small vessel vasculitis (CSVV), treatment is primarily based on case reports and expert opinion, using a range of immunomodulatory or immunosuppressive therapies. This manuscript presents a systematic and stepwise approach to the evaluation of patients presenting with cutaneous vasculitis, as well as the management of those diagnosed with CSVV, using best available evidence. Studies relevant to the classification, evaluation, and management of skin vasculitis are ongoing.

Recent topics related to etiology and clinical manifestations of cutaneous arteritis.

Cutaneous polyarteritis nodosa (cPAN) was first reported by Lindberg in 1931. It has been recognized as a skin-limited vasculitis whose cutaneous histopathological features are indistinguishable from those of PAN. Cutaneous arteritis (CA) was defined as a form of single-organ vasculitis in the revised Chapel Hill Classification and was recognized as the same disease as cPAN. It became known that deficiency of adenosine deaminase 2 (DADA2) cases were included in cases that had been diagnosed with CA. Because of their similarity and differences in the treatment methods, DADA2 should be considered in CA cases, especially if they are diagnosed or developed in early childhood. Cutaneous arteritis may be classified as an immune complex-mediated vasculitis. It was reported that the pathogenesis of anti-lysosomal-associated membrane protein-2 (LAMP-2) antibodies and anti-phosphatidylserine-prothrombin complex (PS/PT) antibodies as good parameters in CA. The main skin manifestations include livedo racemosa, subcutaneous nodules, and ulcers. Although CA is recognized to have a benign clinical course, it has become known that it is easy to relapse. The existence of skin ulcers upon diagnosis or sensory neuropathies was suggested to be a predictor of poor prognosis. Cutaneous arteritis with them may need to be treated with more intensive therapies.

Cutaneous vasculitis and vasculopathy in the era of COVID-19 pandemic.

Cutaneous vasculitides encompass a heterogeneous group of clinicopathological entities, which may occur as single-organ vasculitis of the skin or present as skin-limited variant of systemic vasculitis (i.e., skin-limited ANCA-associated vasculitis), and are triggered by various factors, including infections, drugs and vaccines. The COVID-19 pandemic has challenged us with a variety of both disease- and vaccine-associated skin manifestations, including vasculitis. Among the latter, cutaneous small-vessel vasculitis, previously known as leukocytoclastic vasculitis, seems to be the most reported in either scenario, i.e., natural infection and vaccination. Vasculopathy without true vasculitic changes on histology develops in but a minority of cases, mostly severe/critical COVID-19 patients, and appears to be the result of endothelial injury due to pauci-immune thromboembolic mechanisms. Herein, we provide an overview of the available literature on COVID-19-associated and anti-SARS-CoV-2-vaccine-associated cutaneous vasculitis. Although evidence is mostly limited to isolated reports, with a proportion of cases lacking histopathological confirmation, ample overlap with pre-pandemic forms is shown.

Cutaneous Vasculitides - Clinical Manifestations, Diagnosis, and Aetiology

Cutaneous Vasculitides - Clinical Manifestations, Diagnosis, and Aetiology Abstract. Vasculitides are a heterogeneous group of diseases that are classified differently, for example according to the size of the affected vessel or according to primary and secondary causes. The skin is most frequently affected; it can be involved both as single organ vasculitis and in the context of systemic forms. The combination of skin lesions, their anatomical location and information on the time course provide clues for a differential diagnosis. Purpura, blisters, necrosis, ulcerations and possibly a livedo are characteristic manifestations. Constitutional symptoms such as weight loss, exhaustion, fever, and arthralgias are indicative of a systemic form. It is important to differentiate vasculitides from vasculopathies, which can manifest similarly. The most common form in adults is cutaneous leukocytoclastic angiitis, in children IgA vasculitis (Schönlein-Henoch purpura). Various triggers are possible: infections, drugs, autoimmune diseases, and malignancies, whereby up to 50% remain etiologically unexplained. Skin biopsies and laboratory parameters, if necessary supplemented with imaging, are important steps in the clarification process. Treatment is primarily directed at the elimination of a possible triggering cause. Idiopathic cutaneous leukocytoclastic angiitis usually resolves spontaneously; treatment is symptomatic. In more severe cases, topical corticosteroids or calcineurin antagonists are primarily used. In case of therapeutic resistance, systemic immunosuppressants are recommended.

Expert perspectives on pathological findings in vasculitis.

Pathological findings are important in the diagnosis of vasculitis. However, due to the rarity of the disease, standard textbooks usually devote only a few pages to this topic, and this makes it difficult for clinicians not specializing in vasculitis to fully understand the pathological findings in vasculitis. To address the paucity of information, we present representative pathological findings in vasculitis classified in the 2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides (CHCC2012). The CHCC2012 classifies 26 vasculitides into seven categories: (1) large-vessel vasculitis, (2) medium-vessel vasculitis, (3) small-vessel vasculitis, including antineutrophil cytoplasmic antibody-associated vasculitis and immune complex small-vessel vasculitis, (4) variable-vessel vasculitis, (5) single-organ vasculitis, (6) vasculitis associated with systemic disease, and (7) vasculitis associated with probable aetiology. Moreover, representative pathological findings of vasculitis-related diseases and non-inflammatory vasculopathy not mentioned in the CHCC2012 are also presented. This will be useful for clinicians to refer to typical pathological findings of vasculitis in daily practice.

P042 Spontaneous gallbladder perforation: a rare complication of eosinophilic granulomatosis with polyangiitis

Abstract Background/Aims Gallbladder (GB) perforation is a serious clinical condition, caused by cholecystitis with or without cholelithiasis. Although there have been reports of bowel perforation in many cases of vasculitis, we report to the best of our knowledge, the first case of spontaneous gallbladder perforation following a diagnosis of EGPA. This alerts the clinician to a unique complication of EGPA. Methods A 48-year-old man presented initially to haematology with weight loss and marked eosinophilia, investigations (bone marrow aspirate and trephine, CT chest, abdomen and pelvis) at the time showed no evidence of haematological causes. Subsequently, he developed worsening weakness and paraesthesia of the upper and lower limbs, ongoing for 4 months. He had a background of asthma, and hay fever, which were well-controlled. On examination, he had progressive quadriparesis with extensive muscle wasting. His abdomen was soft non-tender, and he had no skin changes, although he later revealed a photograph of a vasculitic rash affecting the limbs when the symptoms initially presented. Results Laboratory findings revealed raised white blood cells of 46.9 (4-10 x109/L), raised eosinophils of 29.4 (0.01-0.5 x109/L), thrombocytosis of 757 (150-410 x109/L), raised CRP of 172 (0-10mg/L), raised IgE 179(<107 kU/L), and IgG 20.8(6-16 g/L). An extensive infectious screen was performed including HIV, and hepatitis (A-E), which were all negative. Vasculitic screen was negative for PR3 and MPO ANCA. However, nerve conduction studies showed evidence of confluent mononeuritis mimicking acute demyelinating sensory motor neuropathy. Following this, a CT scan was requested to exclude underlying neoplasms and infection which revealed a GB perforation with defect in the distended GB wall. He had no typical symptoms of cholecystitis, favouring an underlying gallbladder necrotizing vasculitis as the cause of GB perforation. The patient was commenced on IV cyclophosphamide and maintained on prednisolone, and azathioprine. A percutaneous cholecystostomy was inserted and immunosuppression continued with antibiotic cover. He had excellent response to therapy and his mobility improved following physiotherapy and rehabilitation. However, he continues to have significant residual weakness of the small muscles of his hand (median and ulnar nerve palsies). An MRCP was later requested, this revealed a contracted GB with no evidence of cholelithiasis or ongoing inflammation. He remained asymptomatic of GB perforation, and as a result, surgeons decided not to proceed with a cholecystectomy. Conclusion Gallbladder vasculitis (GV) can occur as a single organ vasculitis or as part of a systemic vasculitis. In the rare occasion of its occurrence, it mainly presents as symptoms of cholecystitis. Spontaneous GB perforation as a complication of GV has been noted in patients with other vasculitides like Henoch-Schonlein Purpura. However, this is the first report of a spontaneous gallbladder perforation in a patient with EGPA. Disclosure J. Ochogwu: None. A. Madathil: None. H. Mazin: None. D. Makkuni: None.

POS-128 CASE SERIES OF PERI-RENAL COLLECTION IN PATIENTS WITH RAPID PROGRESSIVE RENAL FAILURE-LIKE PRESENTATION– A DIAGNOSTIC CHALLENGE

Background: The vasculitides are defined by the presence of inflammatory leukocytes in vessel walls with reactive damage to mural structures. The typical framework for classification of vasculitides is based upon the predominant size (large, medium, or small) of the involved vessels as per CHCC 2012 which also includes variable vessel vasculitis and single organ vasculitis. In the current case series – both MPA, PAN behaving similarly – questioning the integrity of CHCC and an unmet need for new etiological classification for vasculitis.

Multimodal Approach of Isolated Pulmonary Vasculitis: A Single-Institution Experience

BackgroundIsolated pulmonary vasculitis (IPV) is a single-organ vasculitis of unknown etiology and may mimic chronic thromboembolic pulmonary hypertension (CTEPH). The aim of this study was to review our clinical experience with pulmonary endarterectomy in patients with CTEPH secondary to IPV. MethodsData were collected prospectively for consecutive patients who underwent pulmonary endarterectomy and had a diagnosis of IPV at or after surgery. ResultsWe identified 9 patients (6 women; median age, 48 years [range, 23-55]) with IPV. The diagnosis was confirmed after histopathologic examination of all surgical materials. The mean duration of disease before surgery was 88.0 ± 70.2 months. Exercise-induced dyspnea was the presenting symptom in all patients. Pulmonary endarterectomy was bilateral in 6 patients and unilateral in 3. No deaths occurred; however 1 patient had pulmonary artery stenosis, and stent implantation was performed. All patients received immunosuppressive therapies after surgery. Mean pulmonary artery pressure decreased significantly from 30 mm Hg (range, 19-67) to 21 mm Hg (range, 15-49) after surgery (P < .05). Pulmonary vascular resistance also improved significantly from 270 dyn/s/cm–5 (range, 160-1600) to 153 dyn/s/cm–5 (range, 94-548; P < .05). After a median follow-up of 41 months, all but 1 patient had improved to the New York Heart Association functional class I. ConclusionsIPV can mimic CTEPH, and these patients can be diagnosed with pulmonary endarterectomy. Furthermore surgery has not only diagnostic but also therapeutic value for IPV when stenotic and/or thrombotic lesions are surgically accessible. A multidisciplinary experienced CTEPH team is critical for management of these unique patients.

Vasculitisek bőrön megjelenő formái

Here we summarize vasculitides involving the skin. Among cutaneous vasculitides there are three major groups, one is a systemic vasculitis with cutaneous involvement, another a systemic vasculitis with skin limited appearance, and the last group is a single organ vasculitis, that only affects the skin. We summarize the importance of the proper diagnosis in this heterogeneous group based on both clinical and histopathologic examinations, and present information on the complex underlying pathology

Clinico-pathological and follow-up analysis of 5 skeletal muscle single-organ vasculitis cases

Objectives: To delineate clinico-pathological features, treatment and outcome of skeletal muscle single-organ vasculitis (SM-SOV). Methods: The clinico-pathological characteristic of SM-SOV cases treated over 3 years in China-Japan Friendship Hospital were retrospectively analyzed and the data were compared with the cases from the literature. Results: Five patients (2 women and 3 men) with a median age of 36 years were included in this study. The main clinical manifestations were lower limb myalgia (5/5) and fever (1/5). The most frequent laboratory findings included high erythrocyte sedimentation rate (5/5), high C reactive protein (5/5) and leukocytosis (1/5). No elevated creatine kinase (CK) was found in these cases. Four patients received electromyogram examination and none of them showed myogenic injury. On MRI, hyperintense signals in T2 weighted image (T2WI) and/or short TI inversion recovery (STIR) and normal unenhanced T1 weighted image (T1WI) of one or several leg muscles was founded in all 5 patients. All muscle specimens showed nongranulomatous vasculitis without myonecrosis affecting small sized artery (5/5) in perimysia (75.0%, 3/4) or both perimysia and fascia (25.0%, 1/4). Corticosteroids (5/5) and immunosuppressants (5/5) were the main agents prescribed. With a median follow-up of 24 months, sustained remission was observed in 3 patients, relapses occurred in 2 patients. Conclusion: SM-SOV should be considered for patients with lower limb myalgia, high inflammatory markers and normal/low CK level. The diagnosis of SM-SOV should be applied when there are both histologic evidence of vasculitis and a minimum of 6 months of follow-up surveillance without evidences suggesting extra-muscular involvement. Corticosteroid combined with immunosuppressant is effective.

Medium- and Large-Vessel Vasculitis.

Systemic vasculitides are multisystem blood vessel disorders, which are defined by the size of the vessel predominantly affected, namely small, medium, or large vessels. The term "large vessel" relates to the aorta and its major branches; "medium vessel" refers to the main visceral arteries and veins and their initial branches. The most common causes of large-vessel vasculitis are giant cell arteritis and Takayasu arteritis, and those of medium-vessel arteritis are polyarteritis nodosa and Kawasaki disease. However, there is some overlap, and arteries of any size can potentially be involved in any of the 3 main categories of dominant vessel involvement. In addition to multisystem vasculitides, other forms of vasculitis have been defined, including single-organ vasculitis (eg, isolated aortitis). Prompt identification of vasculitides is important because they are associated with an increased risk of mortality. Left undiagnosed or mismanaged, these conditions may result in serious adverse outcomes that might otherwise have been avoided or minimized. The ethnic and regional differences in the incidence, prevalence, and clinical characteristics of patients with vasculitis should be recognized. Because the clinical presentation of vasculitis is highly variable, the cardiovascular clinician must have a high index of suspicion to establish a reliable and prompt diagnosis. This article reviews the pathophysiology, epidemiology, diagnostic strategies, and management of vasculitis.

Intensity of reaction to tuberculoprotein is not related to severity of disease in patients with single organ vasculitis of the retina

Not available.

S2385 Hepatic Artery Vasculitis: Very Unique Presentation of a Single Organ Vasculitis

INTRODUCTION: Vasculitis usually has a systemic involvement. Rare cases of localized vasculitis have been described, but the exclusive involvement of the hepatic artery is exceptionally rare. We report the case of a patient who developed vasculitis of the right and left hepatic arteries as a very rare presentation of single organ vasculitis. CASE DESCRIPTION/METHODS: A 47-year-old Lady with no medical history was admitted with epigastric discomfort for a couple of weeks. The pain was sharp, localized and progressive. She reported bloating, nausea, and episodes of vomiting, but denied, fever, chills, melena, or other complaints. She was afebrile with stable vital signs and normal examination otherwise. There was minimal tenderness on deep palpation of the epigastrium and right upper quadrant without distension, guarding, or rigidity. Complete blood count and comprehensive metabolic panel including liver enzymes were normal. CRP and ESR were both elevated at 9.2 mg/dL and 62 mm/hr, respectively, but amylase and lipase were normal. CT scan showed diffuse mural thickening with luminal narrowing of the hepatic artery extending into the distal celiac trunk and proximal few millimeters of the splenic artery. These findings are most likely due to vasculitis. Tests for for anti-neutrophil cytoplasmic antibodies, ANA, RF, cryoglobulins, antiphospholipid antibodies, hepatitis B and C serology, HIV serology and the complement levels were all uneventful. Given these radiologic findings, elevated sedimentation rate, CRP, and the evaluation for systemic vasculitis, the patient was treated as isolated Hepatic artery vasculitis. She was started on pulse dose methylprednisolone intravenously for 3 days, after which her ESR and CRP normalized and her symptoms resolved. She was discharged home on prednisone which was later tapered off during clinic follow up. DISCUSSION: Vasculitis usually has a systemic involvement. The exclusive involvement of the hepatic artery of localized vasculitis is very rare, that’s why it’s mandatory to go through full work up for systemic vasculitis to be ruled out. Very few cases of localized vasculitis have been described, but the exclusive involvement of the hepatic artery is exceptionally rare. The outcome was favorable with corticosteroid therapy alone.Figure 1.: CT of the abdomen indicates the common hepatic artery with a thickened rind of soft tissue density and mild stranding in the adjacent fat.Figure 2.: Ct abdomen and pelvis coronal section, the red dot represent the area of hepatic artery with a thickening.Figure 3.: Abdomen and pelvis CT scan sagittal section, the red dot represent the area of hepatic artery with a thickening.

Management of cutaneous vasculitis

Cutaneous vasculitis encompasses cutaneous components of systemic vasculitides, skin-limited variants of systemic vasculitides, such as IgA vasculitis or cutaneous polyarteritis nodosa, and single-organ cutaneous vasculitis, as individualized in 2012 in the Chapel Hill Consensus Conference Nomenclature. In this article, we focus on the management of skin-limited and single-organ vasculitides, often referred to, in clinical practice, as isolated “cutaneous leukocyctoclastic vasculitis”, terms which may correspond to histological findings or descriptions, but are imprecise and not specific. Since most cases of isolated cutaneous vasculitis are self-limited and resolve spontaneously over 3 to 4 weeks, most patients require no systemic treatment. For those with severe, intractable, or chronic and recurring vasculitis, systemic therapy can be indicated and should be tailored to the severity of the disease. High-quality literature is lacking to guide management. Oral glucocorticoids may be required for a short period of time for painful, ulcerative, or otherwise severe disease in order to speed resolution. Among drugs which are reasonable longer-term options are colchicine, dapsone, azathioprine or hydroxychloroquine. Additional studies, including an ongoing multicenter randomized trial, are needed to determine the most effective therapies for skin-limited vasculitis.

Cutaneous Vasculitis: Review on Diagnosis and Clinicopathologic Correlations.

Cutaneous vasculitis is an inflammatory disease affecting the dermal blood vessel walls. The skin is a privileged organ in the setting of vasculitis since it is easily accessible for physical examination and safe biopsy, allowing an accurate characterization of inflammatory lesions. The skin is often involved. Also, cutaneous vasculitis can reflect a cutaneous component of a systemic vasculitis, a skin-limited or skin-dominant expression or variant of a systemic vasculitis, or be a single-organ vasculitis per se. Vasculitis lesions are multiple and polymorphic. They may induce a wide spectrum of clinical manifestations depending on the location and the size of the vessels involved. The depth of affected vessels is correlated with the type of cutaneous lesions. Involvement of small superficial vessels results mostly in urticarial, but relatively persistent plaques, papules, and palpable purpura. Involvement of vessels in the dermohypodermic junction or hypodermis results in ulcers, nodules, or livedo. The type of inflammatory infiltrate is also a key finding for the diagnosis of cutaneous vasculitis. Leukocytoclastic vasculitis is not a disease per se but the result of a pathophysiological process common to different causes. A better knowledge of the vascular anatomy of the skin, elementary lesions, and histological characteristics of dermatologic manifestations would allow a more relevant and more efficient diagnostic approach. We also propose a list of additional exams to be performed in front of skin lesions suggestive of vasculitis. The aim of our article is to provide an overview of elementary skin lesions and clinicopathologic correlations in cutaneous and systemic vasculitis.