Known causes of vasculitis in man

Systemic vasculitis associated withFasciola hepaticainfection

We report the case of a 50-year-old man who presented with systemic vasculitis associated with Fasciola hepatica infection. The patient presented with severe skin, kidney, spleen, ophthalmic, and neurological compromise. An immunological examination for primary vasculitis was negative and other infections were discounted by microbiological and serological analyses. The patient was treated with steroids without clinical response. The Fasciola hepatica infection was confirmed by the presence of specific immunoglobulin G (IgG) serum antibodies detected by a quantitative enzyme-linked immunosorbent assay (ELISA) with an optical density (OD) of 0.483 OD units (normal value<0.170 OD units) and a high-titre complement fixation (1/80 dilution). The patient received treatment with triclabendazole and all symptoms and systemic manifestations resolved within weeks. Hence, this previously unreported vasculitis-associated infection, if identified opportunely, can be treated and cured.

Are classification criteria for vasculitis useful in clinical practice? Observations and lessons from Colombia

INTRODUCTION

Idiopathic systemic vasculitis represents a group of clinical entities having non-specific etiology with the common characteristic of acute or chronic inflammatory compromise of the small and large vessels walls, associated with fibrinoid necrosis.

OBJECTIVES

To describe the most common inflammatory vascular diseases in a long historical cohort of patients from San Juan de Dios Hospital located in Bogota, Colombia using two different systems and a clinical histopathological correlation format, and to make a comparison between them.

METHODS

We reviewed all previously ascertained cases of vasculitis confirmed by biopsy processed between 1953 and 1990, and systematically collected data on all new cases of vasculitis from 1991 to 1997 at the Hospital San Juan de Dios (Bogota-Colombia). The cases were classified in accordance with the Chapel Hill Consensus criteria, and the system proposed by J.T. Lie.

RESULTS

Of 165,556 biopsy tissue specimens obtained during this period from our hospital, 0.18% had vasculitis, perivasculitis or vasculopathy. These included 304 histopathological biopsies from 292 patients. Cutaneous leukocytoclastic vasculitis (64 histological specimens) was the most frequently encountered type of "primary" vasculitis followed by thromboangiitis obliterans (38 specimens), and polyarteritis nodosa (24 specimens). Vasculitis associated with connective tissue diseases (33 specimens) and infection (20 specimens) were the main forms of secondary vasculitis, a category that was omitted from the Chapel Hill consensus report. We found that 65.8% of our histopathological diagnoses could not be classified according to the Chapel Hill classification, and 35.2% could not be classified according to the classification of Lie. Only 8.9% of cases remained unclassified by our system after clinical and histological correlation.

CONCLUSION

Current vasculitis classification schemes are designed for classification, rather that diagnosis of disease and do not adequately address some common forms of inflammatory vascular diseases, including those of infectious etiology and unusual etiology seen in clinical practice. Based on our clinical experience, we suggest a classification outline which practitioners can use which emphasizes correlation of the clinical picture to the histopathology findings for diagnosis and therapy, which may promote better clinical practice and standardization for clinical trials.

The role of infectious agents in the pathogenesis of vasculitis

Numerous human studies and animal models have implicated various infectious agents in the pathogenesis of vasculitis in susceptible hosts. However, the link between infection and vasculitis is very complex and only incompletely understood. In fact, different agents can induce the same type of vasculitis, as the case of leukocytoclastic vasculitis exemplifies. Conversely, the same agent can give rise to a panoply of host responses ranging from a clinically silent infection or localized organ involvement to devastating, widespread vasculitis.

EV71 induces VCAM-1 expression via PDGF receptor, PI3-K/Akt, p38 MAPK, JNK and NF-κB in vascular smooth muscle cells

Enterovirus 71 (EV71) is a widespread virus that causes severe and fatal diseases in patients, including circulation failure. The mechanisms underlying EV71-initiated intracellular signaling pathways to influence host cell functions remain unknown. In this study, we identified a requirement for PDGFR, PI3-K/Akt, p38 MAPK, JNK, and NF-kappaB in the regulation of VCAM-1 expression by rat vascular smooth muscle cells (VSMCs) in response to viral infection. EV71 induced VCAM-1 expression in a time- and viral concentration-dependent manner. Infection of VSMCs with EV71 stimulated VCAM-1 expression and phosphorylation of PDGFR, Akt, and p38 MAPK which were attenuated by AG1296, wortmannin, and SB202190, respectively. The phosphorylation of JNK stimulated by EV71 was not detected under present conditions. In contrast, JNK inhibitor SP600125 inhibited EV71-induced VCAM-1 expression. Furthermore, VCAM-1 expression induced by EV71 was significantly attenuated by a selective NF-kappaB inhibitor (helenalin). Consistently, EV71-stimulated translocation of NF-kappaB into the nucleus and degradation of IkappaB-alpha as well as VCAM-1 mRNA expression was blocked by helenalin, AG1296, SB202190, SP600125, wortmannin, and LY294002. Moreover, the involvement of p38 MAPK, PI3-K/Akt, and NF-kappaB in EV71-induced VCAM-1 expression was reveled by that transfection with dominant negative plasmids of p38 MAPK, p85, Akt, NIK, IKK-alpha, and IKK-beta attenuated these responses. These findings suggest that in VSMCs, EV71-induced VCAM-1 expression was mediated through activation of PDGFR, PI3-K/Akt, p38 MAPK, JNK, and NF-kappaB pathways.

What's new in the aetiopathogenesis of vasculitis?

The cause of the majority of childhood vasculitides is unknown although it is likely that a complex interaction between environmental factors and inherited host responses trigger the disease and determine the vasculitis phenotype. Epidemiological clues continue to implicate infectious triggers in Kawasaki syndrome (KS) and Henoch Schonlein purpura (HSP). Several genetic polymorphisms have now been described in KS and HSP which predispose to disease or predict disease severity. Anti-neutrophil cytoplasmic antibodies (ANCA) are now known to be directly involved in the pathogenesis of vascular injury in ANCA-associated vasculitides, although why some individuals develop ANCA in the first instance is not yet understood. Endothelial injury and repair are active areas of research in vasculitis. It is now possible to track endothelial injury non-invasively in children with vasculitis using surrogate markers of endothelial injury. The vasculogenic pathways involved in vascular repair following vasculitis, including endothelial progenitor cells, are beginning to be studied. It is anticipated that an improved understanding of the aetiopathogenesis of vasculitis in the young will ultimately shape future novel diagnostic and therapeutic approaches and will help us predict which children may develop premature arteriosclerosis in later life.

Diagnostic approach to patients with suspected vasculitis

Vasculitis presents several diagnostic challenges. Firstly, patients could present with protean clinical manifestations with a wide spectrum ranging from isolated cutaneous vasculitis to multisystem involvement. Secondly, there are several medical conditions that could mimic the presentation of vasculitis. The range of differential diagnosis is therefore broad. Thirdly, vasculitis could occur as a primary disorder or be secondary to various medical conditions. It becomes important to differentiate them, as treatment of some forms of vasculitis such as those that are secondary to infection or drugs, is different from that of primary vasculitis. Fourthly, there are several different forms of vasculitis. Some are benign and self limiting, while others have the potential to threaten vital organ function and life. It follows that a rational approach is required during evaluation of patients with suspected vasculitis.

Infection-related vasculitis

Infection-related vasculitis constitutes the most common cause of secondary vasculitis. A great variety of microorganisms can induce directly or indirectly inflammatory vascular damage resulting in vascular occlusion, tissue ischemia, and necrosis. In the developed world hepatitis B and C-related vasculitis remain the most common clinical syndromes, while HIV-associated vasculitis remains a concern in developing countries.

Granulomatous vasculitis

Granulomatous vasculitis is a subset of systemic necrotizing vasculitis and has granulomatous inflammation as the main histopathologic feature. Etiopathogenesis remains poorly understood, although recent advances suggest an important role for certain pro-inflammatory cytokines, such as tumor necrosis factor-alpha. They are a heterogeneous group of clinical disorders with protean manifestations. Serologic abnormalities are present, and the presence of granular cytoplasmic staining-antineutrophil cytoplasmic antibodies is most important and is particularly useful for the diagnosis of active Wegener's granulomatosis. Corticosteroids and cyclophosphamide remain very useful in the treatment of most of these disorders.

Infectious etiology of vasculitis: diagnosis and management

Vasculitides are a heterogeneous group of syndromes characterized by inflammation of the vessel wall. Several microbial pathogens have been known or suspected to cause vasculitis, and the development of molecular biology has promoted the search and confirmation of infectious agents in idiopathic vasculitis. Though several agents present primarily as an infectious process with vasculitis as an occasional manifestation, vasculitis may be the major manifestation of disease. Less definitive, and more controversial, is the role of infection and inflammation of the vessel wall in the pathogenesis of atherosclerotic disease. Clinical features can be nonspecific, and a high index of suspicion is required in order to make a diagnosis of vasculitis. Infection should always be excluded based on appropriate cultures and serologic assays, and, if confirmed, early and aggressive treatment should be instituted. However, in many instances, especially if there is a delay in the diagnosis, surgical intervention becomes necessary to treat the associated anatomic and physiologic sequelae.