Leukocyte-endothelial interactions in antineutrophil cytoplasmic antibody-associated systemic vasculitis

A Model of Left Ventricular Dysfunction Complicated by CAWS Arteritis in DBA/2 Mice

It was reported previously that a Candida albicans water-soluble fraction (CAWS), including a mannoprotein and β-glucan complex, has strong potency in inducing fatal necrotizing arteritis in DBA/2 mice. In this study, histopathological changes and cardiac function were investigated in this system. One mg/day of CAWS was given to DBA/2 mice via peritoneal injection for five days. The CAWS-treated DBA/2 mice were induced aortitis and died at an incidence of 100% within several weeks. Histological findings included stenosis in the left ventricular outflow tract (LVOT) and severe inflammatory changes of the aortic valve with fibrinoid necrosis. Cardiomegaly was observed and heart weight increased 1.62 fold (P < 0.01). Echocardiography revealed a severe reduction in contractility and dilatation of the cavity in the left ventricle (LV): LV fractional shortening (LVFS) decreased from 71% to 38% (P < 0.01), and the LV end-diastolic diameter (LVDd) increased from 2.21 mm to 3.26 mm (P < 0.01). The titer of BNP mRNA increased in the CAWS-treated group. Severe inflammatory changes resulting from CAWS brought about lethal LV dysfunction by aortic valve deformation with LVOT stenosis. This system is proposed as an easy and useful experimental model of heart failure because CAWS arteritis can be induced by CAWS injection alone.

Pathogenesis of diseases associated with antineutrophil cytoplasm autoantibodies

Little is known about the etiologies of diseases associated with circulating antineutrophil cytoplasm autoantibodies (ANCA), such as primary vasculitides and inflammatory bowel diseases. However, the understanding of immune mechanisms supposedly involved in the pathogenesis of these diseases is still growing. In the present review, we first focus on the mechanisms triggering the development of ANCA, including the potential role of microbial superantigens and the possible defect(s) in the progression of apoptosis or in the removal of apoptotic cells. We next concentrate on the contribution of ANCA to the clinical symptoms and on the pathogenic role of ANCA, including the accessibility of ANCA antigens as targets for circulating antibodies and the mode of action of ANCA. Mechanisms of neutrophil activation by ANCA include the engagement of Fcgamma receptors, the possible mechanisms of neutrophil-mediated tissue damage, and the neutrophil-endothelial interaction.

The epidemiology of the primary systemic vasculitides in northwest Spain: implications of the Chapel Hill Consensus Conference definitions

OBJECTIVE

To assess the epidemiology of the primary systemic vasculitides (PSV) in a well-defined population of southern Europe over a 14-year period using the Chapel Hill Consensus Conference (CHCC) definitions.

METHODS

The case records of all patients 15 years or older with vasculitis diagnosed between January 1988 and December 2001 at a single reference hospital in the Lugo region of northwest Spain were reviewed. Incidence rates were age- and sex-adjusted to the European standard population. Patients were classified as having PSV according to the CHCC definitions.

RESULTS

Fifty-four Lugo residents (29 men) fulfilled the CHCC definitions for PSV. The mean age was 60.7 +/- 13.5 years (men: 61.0 +/- 13.4; women: 60.4 +/- 13.8 years). The overall annual incidence of PSV was 13.07/million (95% confidence interval [95% CI] 8.89-19.22). PSV were slightly more common in men. The age-specific incidence showed a clear increase with age. A peak in the 55-64 year age group for the whole group of patients with PSV was observed (34.9/million; 95% CI 28.6-42.6). Nonrandom periodical peaks of incidence every 3 years were only observed when the group of PSV was considered as a whole (P = 0.040). The annual incidence was 2.95/million (95% CI 1.44-6.05) for Wegener's granulomatosis (WG) and 7.91/million (95% CI 4.74-13.20) for microscopic polyangiitis (MPA) (P = 0.035). None of the patients with Churg Strauss syndrome (n = 4) lived in a rural area.

CONCLUSION

Our observations support an increasing incidence of PSV with age. In patients from northwest Spain defined by the CHCC definitions, MPA is more common than WG.

Anti-neutrophil cytoplasm antibody associated vasculitis

Anti-neutrophil cytoplasm antibody associated vasculitides are autoimmune diseases that require treatment with powerful immunosuppressants in order to avert life threatening complications, principally renal failure and lung haemorrhage. Their pathogenesis remains unclear but the circulating autoantibodies are almost certainly instrumental in mediating vascular inflammation. Recent insights into leukocyte-autoantibody interactions support this assertion and may direct future therapeutic strategies, perhaps circumventing some of the toxicity associated with currently used drugs.

Systemic vasculitides

The vasculitides are a heterogeneous group of diseases that are characterized by blood vessel inflammation and necrosis. They have a wide spectrum of manifestations due to the involvement of arteries and other vessels of various sizes and locations. Classification criteria are useful in improving our understanding of the epidemiology of these conditions but they are not diagnostic criteria. In recent years a progressive increase in incidence has been reported. Both giant cell arteritis and Wegener's granulomatosis are more common in the Northern hemisphere. Environmental factors have been implicated in the pathogenesis of these syndromes. Recent studies in patients with large and small-sized vasculitides support a genetic influence in disease susceptibility. They have confirmed the association of giant cell arteritis and Henoch-Schönlein purpura with HLA-DRB1 alleles. Moreover, the polymorphisms of other genes, such as interleukin-1 receptor antagonist, seem to be implicated in disease severity in patients with cutaneous vasculitis.