Distinction of inflammatory lupus vasculitis from antiphospholipid syndrome, which may present with similar clinical manifestations, is of major significance in terms of clinical management. Inflammatory vascular disease is triggered by the in situ formation, or the deposition, of immune complexes within the vessel wall.
Vasculitis may manifest in as high as 56% of lupus patients throughout their life, in contrast to antiphospholipid syndrome which has a prevalence of 15%. Patients with vasculitis are mainly male and tend to be of younger age [32
Antibodies against endothelial cells have been identified as a major endothelial cell cytotoxic effector and have been implicated in the pathogenesis of several connective tissue diseases, predominantly vasculitides [33
]. More than 80% of systemic lupus erythematosus patients are positive for antiendothelial cell antibodies (AECAs) [34
]. Antigens that react with AECAs include heparinlike compounds, DNA and DNA-histone complexes, ribosome proteins, elongation factor 1a, adenyl cyclase-associated protein, profilin II, plasminogen activator inhibitor, fibronectin, and b2-glycoprotein. AECA-endothelial cell interaction attracts monocyte adhesion and induces secretion of chemoattractant proteins and cytokines, thus triggering vasculitis.
Besides AECAs, the presence of antineutrophil cytoplasmic autoantibodies (ANCAs), mainly associated with primary systemic vasculitides, has also been reported in 15-20% of SLE patients [36
Other forms of SLE-related vasculitis include drug-induced vasculitis [37
] and infection-induced vasculitis [38
] either through direct compromise of the vascular wall by pathogens, or through antigen-induced autoimmune and inflammatory processes.