Neutrophil Activation Promotes Fibrinogen Oxidation and Thrombus Formation in Behçet Disease.

BACKGROUND: Behçet disease (BD) is a systemic vasculitis with a broad range of organ involvement, characterized by a multisystemic, immune-inflammatory disorder involving vessels of all sizes and often complicated by thrombosis. Systemic redox imbalance and circulating neutrophil hyperactivation have been observed in BD patients and are thought to be responsible for impaired coagulation. We here focused on the pathogenetic mechanisms potentially linking immune cell activation and thrombosis, and specifically examined whether neutrophil activation can affect fibrinogen modifications and consequently elicit thrombosis. METHODS AND RESULTS: Blood samples were collected from 98 consecutive BD patients attending our dedicated Center and from 70 age- and sex-matched healthy controls; in all patients fibrinogen function and structure, fibrin susceptibility to plasmin-lysis, plasma redox status, leukocyte oxidative stress markers, and possible reactive oxygen species sources were examined. Thrombin-catalyzed fibrin formation and fibrin susceptibility to plasmin-induced lysis were significantly impaired in BD patients (P<0.001). These findings were associated with increased plasma oxidative stress markers (P<0.001) and with a marked carbonylation of fibrinogen (P<0.001), whose secondary structure appeared deeply modified. Neutrophils displayed an enhanced NADPH oxidase activity and increased reactive oxygen species production (P<0.001), which significantly correlated with fibrinogen carbonylation level (r(2)=0.33, P<0.0001), residual ß-band intensity (r(2)=0.07, P<0.01), and fibrinogen clotting ability (r(2)=0.073, P<0.01) CONCLUSIONS: In BD patients, altered fibrinogen structure and impaired fibrinogen function are associated with neutrophil activation and enhanced reactive oxygen species production whose primary source is represented by neutrophil NADPH oxidase.

Thrombosis in Autoimmune Diseases: A Role for Immunosuppressive Treatments?

Autoimmune diseases are not infrequently associated with arterial or venous thrombotic events. Chronic inflammation and immune system impairment are considered the main pathogenetic mechanisms. Some of the drugs used in the treatment of such diseases have been associated with an increased risk of thrombosis. On the contrary, their anti-inflammatory and immune modulator activity could correct some mechanisms leading to thrombosis. In this review, recent evidence available on this topic is examined. There is a lack of adequate studies, but available evidence suggests that glucocorticoids and high-dose immunoglobulins are associated with an increased incidence of venous thromboembolism. Although available data do not allow drawing definite conclusions and more data are needed from future studies and registries, physicians should be aware of these associations.

Microparticles: Bridging the Gap between Autoimmunity and Thrombosis.

Microparticles (MPs) are irregularly shaped small vesicles of heterogeneous size released from the plasma membrane in a tightly controlled process, after different stimuli. MPs have been associated with proinflammatory effects and also with autoimmune processes, being a source of autoantigenic nuclear material, which can form immune complexes. In addition, recent reports have linked a large number of autoimmune disorders to an increased risk of thrombosis, and MPs seem to promote the potential for thrombotic events. A growing mass of evidence supports the idea that MPs could contribute to the generation of an inflammation-induced hypercoagulability state, having a relevant role in the pathogenesis of the thrombotic phenomena associated to autoimmune disease, such as systemic lupus erythematosus, antiphospholipid antibody syndrome, and systemic vasculitis. In this review, we focus on the procoagulant properties of circulating MPs and analyze their contribution to the pathogenesis of autoimmune diseases.

Thrombosis in vasculitis: from pathogenesis to treatment.

In recent years, the relationship between inflammation and thrombosis has been deeply investigated and it is now clear that immune and coagulation systems are functionally interconnected. Inflammation-induced thrombosis is by now considered a feature not only of autoimmune rheumatic diseases, but also of systemic vasculitides such as Behçet's syndrome, ANCA-associated vasculitis or giant cells arteritis, especially during active disease. These findings have important consequences in terms of management and treatment. Indeed, Behçet'syndrome requires immunosuppressive agents for vascular involvement rather than anticoagulation or antiplatelet therapy, and it is conceivable that also in ANCA-associated vasculitis or large vessel-vasculitis an aggressive anti-inflammatory treatment during active disease could reduce the risk of thrombotic events in early stages. In this review we discuss thrombosis in vasculitides, especially in Behçet's syndrome, ANCA-associated vasculitis and large-vessel vasculitis, and provide pathogenetic and clinical clues for the different specialists involved in the care of these patients.

An approach to differential diagnosis of antiphospholipid antibody syndrome and related conditions.

The antiphospholipid antibody syndrome is a systemic, acquired, immune-mediated disorder characterized by episodes of venous, arterial, or microcirculation thrombosis and/or pregnancy abnormalities, associated with the persistent presence of autoantibodies, confirmed at least in two occasions 12 weeks apart, directed to molecular complexes consisting of phospholipids and proteins. Antiphospholipid antibody syndrome should always be considered as a potential diagnosis especially for young patients presenting with a history of thrombotic events, in particular when they occur without any obvious external trigger or any inherited thrombophilic mutation (even if 2006 criteria do not exclude antiphospholipid antibody syndrome in patients with other inherited or acquired prothrombotic conditions), or for women with recurrent pregnancy losses or later fetal deaths. Many other disorders are able to mimic antiphospholipid antibody syndrome, so a broad range of alternative diagnoses should be investigated and ruled out during clinical workup.

Lobular panniculitis with small vessel vasculitis associated with ulcerative colitis.

We report a rare case of lobular panniculitis with small vessel vasculitis, presenting with fever, cutaneous lesions, and systemic manifestations involving the visceral fat and associated with ulcerative colitis. The patient was treated with cyclophosphamide and prednisolone, which successfully cured the systemic disease, with resolution of the inflammatory infiltrates.

Cytotoxic Th1 and Th17 cells infiltrate the intestinal mucosa of Behcet patients and exhibit high levels of TNF-α in early phases of the disease.

BACKGROUND: Gastrointestinal involvement is one of the most serious in Behçet disease, potentially leading to severe complications. Aim of this study was to investigate at mucosal level the T-cell responses in Behçet patients with early intestinal involvement. METHODS: We isolated T cells from intestinal mucosa of 8 patients with intestinal symptoms started within 6 months. T lymphocytes were cloned and analyzed for surface phenotype and cytokines production. RESULTS: We obtained 382 T-cell clones: 324 were CD4+ and 58 were CD8+. Within the 324 CD4+ clones, 195 were able to secrete IFN-γ and TNF-α, but not IL-4, nor IL-17 thus showing a polarized Th1 profile, whereas CD4 clones producing both IFN-γ and IL-17 (Th1/Th17 profile) were 79. Likewise, the number of CD8 clones producing type 1 cytokines was higher than those of CD8 clones producing both type 1 and 2 cytokines.Almost all intestinal-derived T-cell clones expressed perforin-mediated cytotoxicity and Fas-Fas Ligand-mediated pro-apoptotic activity. CONCLUSIONS: Our results indicate that in the early stages of the disease, both Th1 and Th17 cells drive inflammation leading to mucosal damage via abnormal and long-lasting cytokines production as well as via both perforin- and Fas-Fas ligand-mediated cytotoxicity. Finally, all the T cells at mucosal level were able to produce large amount of TNF-α, suggesting that its production is a property of intestinal T cells of patients with early active intestinal disease. These results support the therapy with anti-TNF-α agents and suggest the use of anti-IL-17 monoclonal antibodies in Behçet patients with early intestinal involvement.

Off-label use of rituximab for systemic lupus erythematosus in Europe.

OBJECTIVES: Rituximab (RTX) is a biological treatment used off-label in patients with systemic lupus erythematosus (SLE). This survey aimed to investigate the off-label use of RTX in Europe and compare the characteristics of patients receiving RTX with those receiving conventional therapy. METHODS: Data on patients with SLE receiving RTX were taken from the International Registry for Biologics in SLE retrospective registry and complemented with data on patients with SLE treated with conventional therapy. For nationwide estimates of RTX use in patients with SLE, investigators were asked to provide data through case report forms (CRFs). Countries for which no data were submitted through CRFs, published literature and/or personal communication were used, and for European countries where no data were available, estimates were made on the assumption of similarities with neighbouring countries. RESULTS: The estimated off-label use of RTX in Europe was 0.5%-1.5% of all patients with SLE. In comparison with patients with SLE on conventional therapy, patients treated with RTX had longer disease duration, higher disease activity and were more often treated with immunosuppressives. The most frequent organ manifestations for which either RTX or conventional therapy was initiated were lupus nephritis followed by musculoskeletal and haematological. The reason for treatment was, besides disease control, corticosteroid-sparing for patients treated with conventional therapy. CONCLUSIONS: RTX use for SLE in Europe is restrictive and appears to be used as a last resort in patients for whom other reasonable options have been exhausted.

A new cytofluorimetric approach to evaluate the circulating microparticles in subjects with antiphospholipid antibodies.

INTRODUCTION: Growing evidence supports the idea that microparticles (MPs) could contribute to the pathogenesis of the thrombotic phenomena associated with antiphospholipid antibody syndrome (APS), inducing a hypercoagulable state. But, to date, different approaches to evaluate circulating MPs and conflicting results have been reported. MATERIALS AND METHODS: We have characterized the different circulating subpopulations of MPs in APS patients, and in asymptomatic aPL-positive subjects (carriers) by examining the correlation between the amount and phenotype of MPs and the clinical parameters. Forty-eight subjects were enrolled: 16 with primary APS, 16 aPL-positive, but without clinical criteria for APS (carriers), and 16 healthy subjects. The levels of MPs were evaluated using a new cytofluorimetric approach based on BD Horizon Violet Proliferation dye (VPD) 450. RESULTS AND CONCLUSIONS: Using a new detection cytofluorimetric approach, we demonstrated that the AnnV-negative MPs, underestimated/or excluded in the previous studies, are a large subset of circulating MPs. Also, the levels of MPs in the plasma of aPL positive subjects indicate a state of cellular activation, which is much more pronounced in patients with APS compared to aPL carriers. Moreover, the preliminary data of our pilot study suggest that the evaluation of circulating MPs, in particular PMPs and EMPs, could be used as a surrogate biomarker for platelet and vascular damage monitoring and, if confirmed in a more numerous cohort of patients, it could be used as a prognostic factor to identify aPL positive subjects at higher risk of developing thrombosis.

Behçet's syndrome pathophysiology and potential therapeutic targets.

Behçet syndrome is a systemic inflammatory disorder characterized by multiorgan involvement such as oral and genital ulcers, uveitis, skin lesions as well as by less frequent, but often more severe, central nervous system and vascular manifestations. The pathogenetic mechanisms are still incompletely known; however the interaction between a specific genetic background and environmental or infectious factors certainly contributes to the immune dysregulation that characterizes this disease. The discovery of new immunological pathways in Behçet syndrome pathogenesis may help us to set up new treatments. In this review, we will focus our attention on the possible mechanisms underlying Behçet syndrome pathogenesis and their potential role as novel therapeutic targets.