Coagulation and Fibrinolytic Activity in Behçet's Disease

Vascular Behçet syndrome: from pathogenesis to treatment

Behçet syndrome is a rare, chronic inflammatory disease of unknown aetiopathogenesis, most commonly presenting with mucocutaneous and ocular manifestations. Vascular involvement, most frequently superficial vein and deep vein thrombosis, can occur in up to 50% of patients with Behçet syndrome. Venous thrombosis at atypical sites (inferior and superior vena cava, suprahepatic veins with Budd-Chiari syndrome, portal vein, cerebral sinuses and right atrium and/or ventricle) and arterial involvement (mostly in situ thrombosis and aneurysms of the pulmonary arteries, as well as aneurysms of the abdominal aorta, and peripheral and visceral arteries) are also unique features of Behçet syndrome. Behçet syndrome is considered a natural model of inflammation-induced thrombosis in humans, with an impaired immune-inflammatory response rather than traditional cardiovascular risk factors contributing to thrombogenesis. Specifically, neutrophil hyperactivation and neutrophil-mediated mechanisms of damage directly promote endothelial dysfunction, platelet activation and thrombogenesis in Behçet syndrome. This unusual pathogenesis directly determines the treatment approach, which relies mostly on immunosuppressants rather than anticoagulants for treatment of thrombosis and for secondary prevention. This Review discusses the main histopathological, pathogenetic and clinical aspects of vascular Behçet syndrome, addressing their implications for therapeutic management. Future perspectives in terms of pathogenetic studies, disease monitoring and treatment strategies are also discussed.

[Vascular manifestations of Behcet's disease]

Behçet disease is a multi-systemic complex vasculitis with unknown etiology characterized by different clinical involvements, including mucocutaneous, ocular, vascular, articular, neurological and gastrointestinal manifestations. Growing evidence supports that different phenotypes, characterized by clusters of co-existing involvements, can be distinguished. Namely, the vascular phenotype identifies a specific group of patients who suffer from recurrent inflammatory thrombosis and arterial involvement. Vascular disease develops in up to 40% with a definite male preponderance and is usually an early manifestation. It is one of the main causes of death in Behçet's disease. Venous involvement is significantly more common than arterial disease and lower extremity deep vein thrombosis is its most frequent manifestation. Arterial disease involves mostly pulmonary arteries and aorta and manifests mainly in the form of aneurysms. Glucocorticoids and immunosuppressant's are the recommended first-line treatments in vasculo-Behçet. Furthermore, randomized controlled trials are still needed to assess the role of adding anticoagulation to current standard therapy in venous thrombosis in Behçet's disease and to assess the role of anti-TNF alpha therapy in vasculo-Behçet.

Vascular complications of Behçet disease

Behçet disease is a multi-systemic complex vasculitis with unknown etiology characterized by different clinical involvements, including mucocutaneous, ocular, vascular, articular, neurological, and gastrointestinal manifestations. Growing evidence supports that different phenotypes, characterized by clusters of co-existing involvements, can be distinguished. Namely, the vascular phenotype identifies a specific group of patients who suffer from recurrent inflammatory thrombosis and arterial involvement. Vascular disease develops in up to 40% with a definite male preponderance and is usually an early manifestation. Venous involvement is significantly more common than arterial disease, and lower extremity deep vein thrombosis is its most frequent manifestation. Arterial disease involves mostly pulmonary arteries and aorta and manifests mainly in the form of aneurysms. Glucocorticoids and immunosuppressants are the recommended first-line treatments in vasculo-Behçet. Furthermore, controlled trials are still needed to assess the role of adding anticoagulation to the treatment regimen, with an accent on new oral anticoagulants. Treatment with anti-TNF alpha agents seems promising, but the management strategies are not clear yet.

Epidemiology, morbidity and mortality in Behçet’s disease: a cohort study using The Health Improvement Network (THIN)

Objectives

The epidemiology of Behçet’s disease (BD) has not been well characterized in the UK. Evidence on the risk of cardiovascular disease, thromboembolic disease and mortality in patients with BD compared with the general population is scarce.

Methods

We used a large UK primary care database to investigate the epidemiology of BD. A retrospective matched cohort study was used to assess the following outcomes: risk of cardiovascular, thromboembolic disease and mortality. Controls were selected at a 1:4 ratio (age and gender matched). Cox proportional hazard models were used to derive adjusted hazard ratios (aHR).

Results

The prevalence of BD was 14.61 (95% CI 13.35–15.88) per 100 000 population in 2017. A total of 1281 patients with BD were compared with 5124 age- and gender-matched controls. There was significantly increased risk of ischaemic heart disease [aHR 3.09 (1.28–7.44)], venous thrombosis [aHR 4.80 (2.42–9.54)] and mortality [aHR 1.40 (1.07–1.84)] in patients with BD compared with corresponding controls. Patients with BD were at higher risk of pulmonary embolism compared with corresponding controls at baseline [adjusted odds ratio 4.64 (2.66–8.09), P < 0.0001]. The majority of patients with pulmonary embolism and a diagnosis of BD had pulmonary embolism preceding the diagnosis of BD, not after (87.5%; n = 28/32).

Conclusion

BD has a higher prevalence than previously thought. Physicians should be aware of the increased risk of developing ischaemic heart disease, stroke/transient ischaemic attack and deep venous thrombosis in patients with BD at an earlier age compared with the general population. Risk of embolism in patients with BD might vary across the disease course.

Prevalence of antiphospholipid antibodies in Behçet's disease: A systematic review and meta-analysis

Behçet's disease (BD) is a multifactorial systemic inflammatory disease of unknown aetiology characterised by several clinical manifestations including vascular involvements (i.e., both arterial and venous thrombosis). Antiphospholipid antibodies (aPLs)-including anticardiolipin (aCL), anti-β2-glycoprotein I (β2-GPI) antibodies and lupus anticoagulant (LA) are detected in systemic autoimmune diseases which contribute to thrombosis. The aim of this systematic review and meta-analysis was to evaluate the prevalence of aPLs in patients with BD as compared to controls. A protocol was registered in PROSPERO (Registration No. CRD42018088125) and a systematic literature search was conducted through PubMed, Web of Science, Embase, Scopus and ScienceDirect databases. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects model. Quality assessment was carried out by using the modified 9-star Newcastle-Ottawa Scale (NOS). Publication bias was evaluated via visualisation of contour- enhanced and trim and fill funnel plots along with Begg's and Egger's tests. We included ten case-control studies (a total of 999 participants from 380 BD patients and 619 controls) based on the inclusion criteria. The prevalence of aCL (OR: 12.10, 95% CI: 5.15-28.41, p<0.00001) and anti-β2-GPI antibodies (OR: 23.57, 95% CI: 1.31-423.63, p = 0.03) were statistically significant, however, the prevalence of LA was not significant (OR: 13.77, 95% CI: 0.65-293.59, p = 0.09). The results remained statistically significant from different sensitivity analyses which represented the robustness of this meta-analysis. According to the NOS, 50.0% of the studies were considered as of high methodological quality (low risk of bias). No significant publication bias was detected from contour-enhanced and trim and fill funnel plots or Begg's and Egger's tests. This meta-analysis established that there is a significantly high prevalence of aPLs (i.e., aCL and anti-β2-GPI antibodies) in patients with BD when compared to controls.

Diagnostic Value of Neutrophil-Lymphocyte Ratios and Mean Platelet Volumes in the Activation of Recurrent Aphthous Stomatitis

Recurrent aphthous stomatitis (RAS) is associated with endothelial dysfunction and chronic inflammation. The neutrophil-to-lymphocyte ratio (NLR) and mean platelet voume (MPV) are markers of inflammation and endothelial dysfunction, respectively. In the present report, we discuss the NLR and MPV values of patients with active and inactive RAS. In total, 42 patients (24 females and 18 males) with inactive RAS, 19 patients (12 females and 7 males) with active RAS and 40 healthy controls (24 females and 16 males) were enrolled. MPVs were measured and NLRs calculated. We sought correlations among the MPV and NLR findings in the active and inactive RAS groups and compared them with those of healthy controls. The MPV and NLR values were significantly higher in patients with active than inactive RAS (MPV, 10.6 ± 2.9 vs. 7.1 ± 2.4 fL, p < 0.001; NLR, 3.74 ± 1.9 vs. 2.1 ± 1.43, p = 0.015). In addition, both MPV and NLR values in patients with inactive RAS didn't differ significantly compared to values observed in the controls (MPV, 7.1 ± 2.4 vs. 6.9 ± 2.1 fL, p = 0.126; NLR, 2.1 ± 1.43 vs. 2.07 ± 0.96, p = 0.525). Both the NLR and MPV were significantly higher in patients with active RAS, emphasising the importance of inflammation and endothelial dysfunction in the pathophysiology of RAS activation.

Decreased Protein Z Concentrations Complicating the Hypercoagulable State of Behqet's Disease

Protein Z is a vitamin-K-dependent plasma protein that serves as a cofactor for the inhibition of factor Xa. Although the precise physiologic function of protein Z is still unknown, abnornal plasma protein Z concentrations have been associated with a number of thrombotic disease states. There is the evidence of universal activation of the hemostatic system in Behqet's disease (BD), which represents a hypercoagulable/prothrombotic state. Circulating protein Z levels in patients with BD were evaluated. Plasma protein Z concentrations were assayed in 24 patients with BD (male/female: 13/11, mean age 35.4 years) and in 24 healthy controls (males/females: 14/10, mean age 59.8 years). The disease duration was 10.6 years (range, 1-30 years). None of the subjects in either group had received anticoagulants within 3 weeks before the study, and none of them had liver dysfunction. Patients complicated with vascular disease were also excluded from the study. Mean plasma concentrations of protein Z were 141 ng/mL (range, 56.8-257) in healthy controls and 107.8 ng/mL (range, 21.2-202) in BD patients (p<0.05). There was a positive correlation between the disease duration and protein Z levels in the study group (p<0.05, r=0.448). Alterations of protein Z concentrations could complicate the pathobiology of the prothrombotic state of BD. Furthermore, the tendency of increment in the protein Z with the passage of time may reflect the diminution of the disease activity.

Thrombosis in vasculitic disorders-clinical manifestations, pathogenesis and management

Inflammation and coagulation are known to affect each other in many ways. Vasculitis represents a group of disorders where blood vessels (small, medium, large or variable) are infiltrated with inflammatory cells. Accumulating evidence in the literature suggests both clinical and physiological association between vasculitis and thrombosis. Vasculitis-associated thrombosis involves arteries and veins, and a tight connection has been reported between the activity of vasculitis and the appearance of thrombosis. Pathophysiology of these relations is complex and not completely understood. While thrombophilic factors are associated with vasculitis, it remains unclear whether a true association with clinical thrombosis is present. Furthermore, several factors leading to hemostasis, endothelial injury and induction of microparticles were described as possibly accounting for thrombosis. Management of thrombosis in vasculitis patients is challenging and should be further assessed in randomized controlled studies. The current review describes clinical manifestations, pathogenesis and management of thrombosis associated with different vasculitides.

Identification of possible pathogenic pathways in Behçet's disease using genome-wide association study data from two different populations

Behçet's disease (BD) is a multi-system inflammatory disorder of unknown etiology. Two recent genome-wide association studies (GWASs) of BD confirmed a strong association with the MHC class I region and identified two non-HLA common genetic variations. In complex diseases, multiple factors may target different sets of genes in the same pathway and thus may cause the same disease phenotype. We therefore hypothesized that identification of disease-associated pathways is critical to elucidate mechanisms underlying BD, and those pathways may be conserved within and across populations. To identify the disease-associated pathways, we developed a novel methodology that combines nominally significant evidence of genetic association with current knowledge of biochemical pathways, protein-protein interaction networks, and functional information of selected SNPs. Using this methodology, we searched for the disease-related pathways in two BD GWASs in Turkish and Japanese case-control groups. We found that 6 of the top 10 identified pathways in both populations were overlapping, even though there were few significantly conserved SNPs/genes within and between populations. The probability of random occurrence of such an event was 2.24E-39. These shared pathways were focal adhesion, MAPK signaling, TGF-β signaling, ECM-receptor interaction, complement and coagulation cascades, and proteasome pathways. Even though each individual has a unique combination of factors involved in their disease development, the targeted pathways are expected to be mostly the same. Hence, the identification of shared pathways between the Turkish and the Japanese patients using GWAS data may help further elucidate the inflammatory mechanisms in BD pathogenesis.

Mean platelet volume in ocular Behçet's disease

Objective. To determine whether mean platelet volume (MPV) is an indicator of disease severity in ocular Behçet's Disease (BD). Materials and Methods. The study population was 30 newly diagnosed ocular BD patients who presented with active uveitis. These patients had no past history of smoking, drug use, or systemic diseases including diabetes mellitus, hypertension, cardiovascular disease, and renal disease. A control group consisting of 34 healthy individuals was included for comparison. MPV measurements were performed serially upon presentation with active uveitis and at one and three month thereafter in BD group whereas only at presentation in the controls. Results. Upon presentation with active uveitis, the mean MPV levels were 7.88 ± 1.14 femtoliters (fL) for BD group. During the posttreatment follow-up period at first and third months, BD patients demonstrated a mean MPV level of 7.71 ± 1.12 fL and 7.65 ± 1.04 fL, respectively. The mean MPV value of control group, was 8.39 ± 0.66 fL at presentation. Fluctuations in MPV values were not significant in the BD group, while there was a significant difference between the initial measurements of the BD and control groups. Conclusion. MPV measurement in ocular BD is not a predictive laboratory test to determine the clinical improvement in early stages following classical immunosuppressive treatment.

Behçet's disease: new insight into the relationship between procoagulant state, endothelial activation/damage and disease activity

BACKGROUND

Behçet disease (BD) is associated with a prothrombotic state of unknown origin that may lead to life-threatening events. Calibrated Automated Thrombogram (CAT) and Rotational Thromboelastometry (ROTEM) are two global haemostasis assays that may reveal new insights into the physiopathological mechanisms of the disease and its procoagulant condition.

METHODS

23 BD patients who had no signs or symptoms of current thrombosis and 33 age- and sex-matched controls were included in the study. We performed ROTEM and CAT tests and assessed erythrocyte count, platelet count, platelet contribution to clot formation and plasma levels of tissue-type plasminogen activator, plasminogen activator inhibitor type 1 (PAI-1), fibrinogen, C-reactive protein (CRP), thrombin-antithrombin III complex (TAT), D-dimer and E-selectin (ES).

RESULTS

Both ROTEM and CAT tests showed a hypercoagulable state in the BD patients. Plasma levels of PAI-1, fibrinogen, TAT, CRP and ES were significantly increased in this group compared to controls. The disease activity (DA) was significantly correlated with levels of ES and the maximum clot firmness, and this last one, in turn, correlated with rising levels of ES, PAI-1, CRP and fibrinogen. CAT parameters did not correlate with DA or ES.

CONCLUSIONS

Both ROTEM and CAT tests reveal that patients with BD have a procoagulant state even in the absence of thrombosis. ROTEM test indicates that increased levels of fibrinogen and PAI-1 may be involved in the prothrombotic state of this pathology, while platelets do not significantly contribute. Moreover, CAT assay demonstrate that plasma from BD patients is able to generate more thrombin than controls in response to the same stimulus and that this effect is independent of the DA and the endothelial impairment suggesting the involvement of another factor in the hypercoagulable state observed in BD patients. This study also shows that endothelium activation/damage may be a contributing factor in both the procoagulant and clinical conditions of BD, as shown by the direct correlation between ES levels, ROTEM parameters and DA.

Ocular Behçet disease: current therapeutic approaches

PURPOSE OF REVIEW

To alert physician to timely recognition and current treatment of recurrent hypopyon iridocyclitis or panuveitis in ocular Behçet disease (OBD).

RECENT FINDINGS

Interferon-α, rituximab, intravitreal triamcinolone, and biological response modifiers by tumor necrosis factor inhibitors such as infliximab and adalimumab are being used increasingly for the treatment of severe sight-threatening ocular inflammation including retinal vasculitis and cystoid macular edema (CME).

SUMMARY

Biological agents offer tremendous potential in the treatment of OBD. Given that OBD predominantly afflicts the younger adults in their most productive years, dermatologist, rheumatologist, internist, or general practitioners supervising patients with oculo-articulo-oromucocutaneous syndromes should be aware of systemic Behçet disease. Early recognition of ocular involvement is important and such patients should strongly be instructed to visit immediately an ophthalmologist, as uveitis management differs from extraocular involvements with high ocular morbidity from sight-threatening complications due to relapsing inflammatory attacks in the posterior segment of the eye. A single infliximab infusion should be considered for the control of acute panuveitis, whereas repeated long-term infliximab infusions were proved to be more effective in reducing the number of episodes in refractory uveoretinitis with faster regression and complete remission of CME.

New insights into the pathogenesis of Behçet's disease

Behçet's disease (BD) is a recurrent systemic inflammatory disorder of unknown origin characterized by oral and genital mucous ulcer, uveitis, and skin lesions. Involvement of large vessels, central nervous system (CNS), gastrointestinal tract and thrombotic events are less frequent but can be life threatening. The aim of this review is to provide new insights into the pathogenesis of BD. Over the past year substantial advances have been done in the understanding of the genetic [1,2] and immunology [3] of BD. BD is at the crossroad between autoimmune and autoinflammatory syndromes. In common with autoimmune diseases BD shares class I MHC association. However, in contrast to autoimmune disorders, BD has clinical features that seem to be mostly autoinflammatory. The pathogenesis of BD is still unknown, but major determinants of the genetic and immune system abnormalities have been reported recently. Triggering infectious factors are supposed to participate in the outbreak of BD in genetically predisposed patients. Two recent large genome-wide association study (GWAS) conducted in Turkey and Japan reported association between single nucleotide polymorphism (SNP) of interleukin (IL)-10 and IL-23R/IL-12RB2 genes and BD. New insights into the perturbations of T cell homeostasis of BD recently emerged. We have recently demonstrated the promotion of Th17 responses and the suppression of regulatory T cells (Tregs) that were driven by interleukin (IL)-21 production and that correlates with BD activity. Inflammatory cells within BD inflammatory lesions included mostly neutrophils, Th1 and Th17 cells, and cytotoxic CD8+ and γδ T cells. Altogether, the recent progresses in the knowledge of BD pathogenesis pave the way for innovative therapy.

Hyperhomocysteinaemia in Behçet's Disease

Objectives. The aim of this study was to investigate if hyperhomocysteinaemia is a contributive risk factor for the pathogenesis and the activity of Behçet's disease (BD). Design and Methods. Fifty four patients fullfiling the criteria of the International Study Group for BD were enrolled. Fifty healthy volunteers matched for age and sex with the BD group were included as a negative control group. Patients, with any condition that might affect plasma homocysteine concentration, were excluded. Results. Mean serum homocysteine concentration was significantly higher in patients with BD than in the healthy controls (P < .001), in patients with active disease (P = .04), and in masculine gender (P = .05). There was no significant difference between homocysteine level and clinical involvement. Conclusions. We demonstrated that plasma total homocysteine level (tHcy) is increased in BD and correlated with disease activity. No association was found between homocysteine levels and clinical involvement.

Pediatric Behçet’s Disease and Thromboses

Objective.

To describe the characteristics of a group of pediatric patients with Behçet’s disease (BD) who presented at least 1 episode of thrombosis during their disease course.

Methods.

We made a retrospective chart review of the clinical, biological, and radiological data of children with BD who presented at least 1 episode of either arterial or venous thrombosis. Data were extracted from both an international pediatric Behçet cohort and files referred from 7 French centers.

Results.

Twenty-one patients were included. Diagnosis of BD was based on the criteria of the International Study Group for BD. Main locations for thrombosis were the cerebral sinuses, in 11 patients (52.4%); and lower limbs, in 9 patients (40.9%). Recurrent episodes were observed in 4 patients (21%). Thrombophilia measurements were normal in 14 patients out of 21, while anticardiolipin antibodies were positive in 4 patients, and 2 out of 21 had protein C deficiency. One patient had lupus anticoagulant. All patients were treated with colchicine. Corticosteroids were also added for variable periods in 13 patients. Five patients out of 21 were treated with anticoagulants (heparin, then anti-vitamin K) and 3 with antiplatelets (acetylsalicylic acid).

Conclusion.

Thromboses are a serious complication of BD and may occur early in the disease course. The presence of thrombophilic markers could increase the risk of thrombosis in BD, but the size of our population does not allow any conclusion. An international cohort (PED-BD) is currently in place and will allow study of such cases longitudinally, as well as assessment of the elements that correlate with an increased risk of thrombosis in children with BD.

Behçet’s Disease as a Model of Venous Thrombosis

Behçet’s disease (BD) is a chronic inflammatory disease of unknown aetiology characterized by recurrent oral, genital aphthous ulcerations, uveitis, skin lesions and other multisystem affections associated with vasculitis. Different types of vessels, predominantly veins, can be affected in BD. The frequency of vascular lesions in BD, such as superficial and deep venous thromboses, arterial aneurysms and occlusions, ranges between 7-29%.

In this review, various factors of thrombogenesis in BD, particularly pro- and antithrombotic endothelial and non-endothelial factors, factors of coagulation, platelet activation and rheological changes are presented and discussed from positions of Virchow’s triad of venous thrombosis.

Despite advances in understanding of thrombogenesis in BD, still many issues of diagnosis and targeted preventive and therapeutic measures remain unresolved. Further studies are needed to clarify the pathobiology of BD-related thrombosis and to provide the clinicians with recommendations over the utility, safety and effectiveness of the antithrombotic therapy in BD.

Fibrinolytic inhibitor levels and polymorphisms in Behçet disease and their association with thrombosis

This study aimed to assess the fibrinolytic inhibitors and their association with thrombosis in Behçet disease. Thrombin activatable fibrinolysis inhibitor (TAFI) (P < 0.001) and plasminogen activator inhibitor-1 (PAI-1) levels (P = 0.022) were significantly higher in 79 patients than in 84 controls. No significant differences were observed in CPB2 (TAFI) Thr325Ile and SERPINE1 (PAI1) 4G/5G polymorphism distribution between patients and controls. TAFI activity levels were significantly higher in patients with thrombosis than in those without thrombosis (P = 0.024). In conclusion, the increased TAFI levels in Behçet disease could contribute to the increased risk of thrombosis observed in these patients.

Intima-media thickness and arterial stiffness of carotid artery in Korean patients with Behçet's disease

Behçet's disease (BD) is a systemic vasculitis involving diverse sizes of arteries and veins. We performed this study to evaluate the vascular changes by assessment of the arterial stiffness and intima-media thickness (IMT) of carotid artery in Korean patients with BD. Forty-one patients with BD and age-, and sex-matched 53 healthy subjects were recruited in this study. Carotid arterial stiffness and IMT were assessed by using high-resolution B-mode ultrasonography. Arterial stiffness parameters such as carotid arterial distensibility coefficient, stiffness index, and incremental elastic modulus (E(inc)) were significantly increased in BD patients compared with those in healthy subjects, but not in IMT. Positive relationship was noted between age and IMT, whereas age of onset was significantly associated with arterial stiffness in BD. This finding suggests impaired endothelial function before visible structural changes of arterial wall in BD. Age and age of onset may be an independent risk factor for carotid IMT and arterial stiffness, respectively. Further studies in more large populations are required to confirm our results.

Homocysteine: An activity marker in Behçet's disease?

BACKGROUND

Behçet's disease (BD) is a chronic multisystem inflammatory disorder commonly complicated by vascular thrombosis.

OBJECTIVE

In this study, we investigated whether hyperhomocysteinaemia, being a well known risk factor for atherothrombogenesis, is also a contributive risk factor for the pathogenesis and the activation of Behçet's disease.

METHODS

Sixty-four patients fulfilling the criteria of the International Study Group for Behçet's disease (48 males, 16 females, 33+/-8 years) were enrolled. They were separated into two groups with respect to activation features of Behçet's disease. Additionally, we collected the blood samples from 13 patients with BD in both active stage and in inactive stage. Twenty-six healthy individuals were included as a negative control group. Serum total homocysteine (Hcy) levels were determined by chemiluminescence immunoassay.

RESULTS

Mean serum homocysteine concentrations in total BD patients were significantly higher than in the healthy controls (11.7+/-4.6 versus 8.7+/-2.8micromol/L, p<0.01). Mean serum homocysteine concentrations in the active patients were significantly higher than in the inactive patients and the healthy controls (13.3+/-3.6; 10.8+/-5.0; 8.7+/-2.8micromol/L, respectively) (p<0.05 and p<0.001, respectively). There was no significant difference between the patients with inactive disease and the healthy controls. When the active and the inactive stage of 13 patients with BD were compared, we found that mean serum total homocysteine levels were higher in the active stage than in the inactive stage (p<0.05).

CONCLUSION

Hyperhomocysteinaemia may be responsible for the endothelial damage in BD and assumed to be a risk factor and a marker for activation of BD.

Decreased protein S activity is related to the disease activity of Behcet's disease

We wanted to see whether the active inflammation in Behcet's disease (BD) can cause a thrombotic disorder by decreasing the protein S (PS) activity, and we evaluated the relationship between the decreased PS activity and the disease activity of BD. We included 122 patients with BD whose PS activity levels were measured. In 51 patients, the PS activity was measured again when there were changes in the number of items of "The Behcet's Disease Current Activity Form (BDCAF)". The thrombosis rate was 2.5% (3/122), and the PS activity was low in all three of the patients with thrombosis. The incidence of low PS activity in the total 122 BD patients was 27% (33/122). The incidence of the low PS activity in the active BD patients was 33.7% (31/92), and this was significantly more frequent than in the inactive BD patients, (6.7%, 2/30) (chi(2)-test, P value = 0.0038). The decrease of PS activity had good correlation with the increase of the number of BDCAF items (r = -0.351, P value = 0.012). The PS activity decrease is related to the BD activity. The low PS activity can be the risk factor for thrombotic disorder and also the activity marker for BD and other inflammatory diseases.

Characteristics of vascular involvement in Behçet's disease

OBJECTIVE

Behçet's disease (BD) is a multisystemic inflammatory disorder classified among the vasculitides, which can affect all types and sizes of blood vessels. Vascular involvement may be seen in 25-50% of BD patients. In this study, we examined the characteristics of vascular involvement in patients with BD.

METHODS

One hundred and eighty patients with BD were included in the study. The diagnosis of vascular involvement was made on clinical signs, by Doppler ultrasonography and/or angiography using computed tomographic or magnetic resonance techniques where appropriate. Detailed clinical characteristics were recorded for each patient.

RESULTS

Seventy-one patients (39.4%) had vascular involvement. In patients with vascular lesions, the frequency of male sex was significantly higher than in patients without vascular lesions (89.8% vs. 63.3%, respectively; p < 0.001). Of 71 BD patients with vascular involvement, 68 had venous lesions (95.8%). Three patients had arterial lesions without venous thrombosis. Eleven patients had arterial involvement with venous thrombosis. The most frequent type of vascular involvement was deep venous thrombosis in the lower extremities (n = 56, 78.9%). There was a significant association between deep venous thrombosis and superficial thrombophlebitis (r = 0.325, p < 0.01). Twenty-four patients (33.8%) had vena cava thrombosis and two had vena hepatica thrombosis. In patients with vascular involvement, the frequency of erythema nodosum was significantly higher (p = 0.001) and the frequency of ocular involvement was significantly lower (p < 0.05) than in patients without vascular involvement.

CONCLUSION

Our study illustrates the frequency and significance of vascular involvement in BD.

Haemorheological alterations in Behçet's disease are not related to a tendency for venous thrombosis

INTRODUCTION

Behçet's disease is associated with an increased risk of thrombosis, although the prothrombotic mechanisms are unclear. Alterations in blood rheology, particularly increased erythrocyte aggregation, might play a role in the development of such thrombotic events.

MATERIALS AND METHODS

We measured plasma lipids, fibrinogen, haematocrit, erythrocite aggregation, erythrocyte deformability, blood viscosity, plasma viscosity and erythrocyte indexes in patients with a nonactive disease at sampling, and in a well-matched control group. The patient group comprised 42 patients with BD (21 male, 21 female aged 43+/-12 years) and the control group comprised 46 healthy volunteers (23 male, 23 female aged 45+/-13 years). Twelve of the 42 patients with BD had a previous documented history of deep vein thrombosis at least 6 months before entering the study, and the other 30 did not.

RESULTS

Compared with controls, patients showed statistically higher fibrinogen concentrations (P=0.001), plasma viscosity (P=0.002), blood viscosity (P=0.006) and erythrocyte aggregation, both at stasis (P=0.001) and at a low shear rate (P=0.002): the other rheological parameters were not statistically significant. No differences were observed in the rheological parameters when patients with and without previous thrombotic episodes were compared.

CONCLUSIONS

Although patients with BD show a moderate hyperviscosity syndrome, possibly related to chronic inflammation, this does not seem to play a role in the development of thrombotic events.

Thrombin activatable fibrinolysis inhibitor in Behçet's disease

INTRODUCTION

Thrombin activatable fibrinolysis inhibitor (TAFI) is a procarboxypeptidase downregulating plasmin formation, thereby causing a tendency for thrombosis development. Since, Behçet's disease (BD) is a systemic vasculitis, which is commonly complicated by arterial and venous thrombosis, we aimed to find out plasma TAFI levels in BD, compared with healthy controls. We also searched whether plasma TAFI levels were significantly different between Behçet's subgroups with and without thrombosis.

MATERIALS AND METHODS

In this study, 105 BD patients (M/F: 64/41; mean age 36+/-1 years), followed up by Ege University Rheumatology Department were enrolled. The exclusion criteria were hemophilia, hyperlipidemia, diabetes mellitus, hepatic diseases renal failure, antiphospholipid positivity, oral contraceptive use and pregnancy. Age-and sex-matched healthy controls (n=53) were also included. Plasma TAFI levels were measured by ELISA. Since TAFI is also an acute-phase reactant, we also measured other inflammatory markers such as C-reactive protein (CRP).

RESULTS

Plasma TAFI levels were significantly higher in Behçet's patients (91.1+/-7.4 ng/ml) compared with healthy controls (14.3+/-4.5 ng/ml) (P<0.001), but there were no significant difference between the subgroups with and without thrombosis. In BD, there was no correlation between plasma TAFI levels and CRP.

CONCLUSIONS

Regardless of manifest thrombosis, plasma TAFI levels in BD were significantly higher than in healthy controls. High TAFI levels might possibly contribute to the thrombotic tendency in BD. Future studies investigating TAFI gene polymorphism and functional activity are clearly needed, to clarify the exact role of TAFI in Behçet's thrombosis.

Endothelial cell activation and hypercoagulability in ocular Behçet's disease

PURPOSE

To investigate the presence of a hypercoagulable state and vascular endothelial dysfunction in patients with ocular Behçet's disease and relate the results to the activity of ocular and systemic involvement.

DESIGN

Cross-sectional laboratory and clinical study.

METHODS

Prospective study of blood samples of 24 patients diagnosed with ocular Behçet's disease, which were analyzed for factor VIII, factor XI, von Willebrand factor antigen and ristocetin (vWF ag and risto), antithrombin III (ATIII), protein C and S, fibrinogen and activated protein C (APC) resistance. The results were compared with 40 healthy controls and analyzed for association with ocular and systemic clinical features.

RESULTS

The mean values of factor VIII, factor XI, vWF ag, vWF risto, ATIII, and fibrinogen were significantly raised compared to healthy population (for all: P <.001). Most striking were factor VIII activity levels above 130% in 79% (19 of 24) of our patients. 67% (16 of 24) had levels of factor VIII above 150%, which correlates with a fivefold increase in risk of thrombosis. Other prothrombogenic factors were negative in all but 2 patients (1 protein C deficiency, 1 factor V Leiden mutation). Endothelial cell activation, measured by vWF activity, revealed elevated levels in 42% (10/24). Complete/incomplete Behçet's disease patients with present or previous macular edema had significantly higher FVIII levels than complete/incomplete Behçet's disease patients who had never shown any signs of macular edema (P =.04). Further correlations between the laboratory results and clinical symptoms were not found.

CONCLUSIONS

We found a generalized hypercoagulable state with endothelial cell activation in ocular Behçet's disease, irrespectively of current ocular disease activity.

Serum homocysteine level is higher in Behçet’s disease with vascular involvement

OBJECTIVE

Behçet's disease (BD) is a multisystemic inflammatory disorder of unknown etiology that is sometimes associated with thrombosis. However, the mechanism of hypercoagulability is not known. In this study, we investigated whether hyperhomocysteinemia, being a well-known risk factor for thrombosis, is also a contributing risk factor to venous and arterial thromboses of BD.

METHODS

Forty-five patients with BD and 40 healthy subjects were included in the study. Sixteen patients had vascular involvement. Serum homocysteine levels were determined by fluorescence polarization immunoassay.

RESULTS

In male patients, the frequency of vascular involvement was significantly higher than in females (46.7% vs 13.3%, P < 0.05). Serum homocysteine levels were significantly higher in patients with BD than healthy controls (P < 0.01), in patients with vascular involvement than those with mucocutaneous involvement (P < 0.01) and healthy controls (P = 0.001), and in male patients than in female patients (P < 0.001). There was no significant difference in homocysteine levels between the BD patients with mucocutaneous involvement and healthy subjects. In multiple regression analysis, serum homocysteine level was independently associated with thrombosis (odds ratio 1.29, P < 0.01), but male sex was not.

CONCLUSIONS

This preliminary study suggests that elevated serum homocysteine levels may play some role in the development of venous and arterial thromboses in BD.

Coagulation parameters and plasma total homocysteine levels in Behcet's disease

Behcet's disease (BD) is a multisystemic inflammatory disorder of unknown etiology that is sometimes associated with thrombosis in addition to systemic manifestations. However, the mechanism of hypercoagulability is not known. We evaluated the coagulation and fibrinolytic activities and the plasma total homocysteine levels of Korean BD patients in two cross-sectional studies. In the first study regarding coagulation and fibrinolytic activities, the levels of fibrinogen and von Willebrand factor (vWF) antigen were significantly higher in the BD patients than in the healthy controls (387.7+/-24.3 versus 240.6+/-8.8 mg/dl, p<0.001, and 131.9+/-8.8 versus 105.2+/-0.3%, p<0.01, respectively). The level of antithrombin III (AT III) was significantly lower in the BD patients (92.8+/-3.2 versus 106.3+/-2.6%, p<0.005). No differences were observed in the levels of plasminogen, protein C, or protein S activities. Activated protein C (APC) resistance was not observed in any BD patients. In the second study, the plasma total homocysteine levels of patients with a history of thrombosis (11.9+/-3.0 micromol/l) or disease activity (12.5+/-3.8 micromol/l) were found to be significantly higher than those of the controls (9.2+/-2.6 micromol/l, p<0.05, both). The plasma homocysteine concentrations in the thrombosis patients were positively correlated with plasma vWF levels; a relationship which suggests injury of the vascular endothelium (Spearman coefficient=0.857, p<0.01). Therefore, coagulation abnormality did not contribute to thrombotic complications, and higher levels of homocysteine may play a role in the hypercoagulablity of BD patients.

Pathological haemostasis and "prothrombotic state" in Behçet's disease

Behçet's disease (BD) is a widespread occlusive-type vasculitis with life-threatening manifestations. The vasculopathy of BD is unique and any type of vessel can be involved. Moreover, vascular lesions in BD represent an occlusive nature suggesting a hypercoagulable/prothrombotic state. The data concerning the genetic defects of the coagulation cascade are expanding. There is evidence of universal activation of haemostatic system in BD. Procoagulant markers of thrombosis are elevated reflecting intravenous excessive thrombin formation. Defective fibrinolysis with impaired fibrinolytic kinetics may have a role in the hypercoagulable/prothrombotic state of BD. Endothelial cell injury and/or pathological activation is well documented in BD. The aim of this paper is to review current literature knowledge and our experience regarding the unresolved complicated issues of genetic thrombotic defects, in vivo haemostatic markers, coagulation inhibitors, impaired fibrinolysis, and endothelial injury/dysfunction of the hypercoagulable/prothrombotic state of BD. The clinical aspects of vascular thrombosis, the genetic basis of coagulation, coagulation inhibitors, fibrinolysis inhibitors, and endothelial dysfunction are reviewed. Challenges and future prospects regarding the prothrombotic state of BD are discussed together with new promising antithrombotic and antiplatelet treatment strategies. Better understanding of the exact pathogenesis of the hypercoagulable/prothrombotic state of this disease may help to develop novel therapeutic approaches offering a better outcome for Behçet's patients with thrombosis.

Vascular involvement in Behçet's disease: relation with thrombophilic factors, coagulation activation, and thrombomodulin

PURPOSE

Thrombosis, usually venous, occurs in 10% to 25% of patients with Behçet's disease, but its pathogenesis is poorly understood. We evaluated parameters of hemostasis and their relation with thrombosis in a series of patients with Behçet's disease.

SUBJECTS AND METHODS

We studied 38 patients with Behçet's disease (13 with venous thrombosis), 38 patients with venous thrombosis without thrombophilia, and 100 control subjects. Levels or presence of protein C, protein S, antithrombin, methylenetetrahydrofolate reductase C677T, factor V Leiden, prothrombin gene G20210A, antiphospholipid antibodies, plasminogen, tissue-type plasminogen activator (tPA), type-1 tPA inhibitor (PAI-1), PAI-1 4G/5G polymorphism, prothrombin fragment 1+2, plasmin/alpha(2)-antiplasmin complexes, thrombomodulin, and activated factors VII and XII were determined.

RESULTS

There were no deficiencies in protein C, protein S, antithrombin, or factor V Leiden in the patients with Behçet's disease, nor was there evidence of most other thrombotic abnormalities. Compared with control subjects, however, the Behçet's disease group had elevated mean (+/- SD) levels of prothrombin fragment 1+2 (2091 +/- 1323 pmol/L vs. 804 +/- 398 pmol/L, P <0.001), plasmin/alpha2-antiplasmin complexes (410 +/- 220 microg/L vs. 214 +/- 92 microg/L, P <0.001), and thrombomodulin (37 +/- 24 ng/mL vs. 27 +/- 10 ng/mL, P <0.001). These levels did not differ between patients with or without thrombosis.

CONCLUSIONS

Thrombophilic factors do not seem to explain most thromboses in Behçet's disease. There is increased thrombin generation, fibrinolysis, and thrombomodulin in Behçet's disease, but these abnormalities are not related to thrombosis.

Increased levels of tissue factor pathway inhibitor may reflect disease activity and play a role in thrombotic tendency in Behçet's disease

Tissue factor pathway inhibitor (TFPI) is a Kunitz-type proteinase inhibitor that has a crucial role in haemostasis and is primarily synthesized in the vascular endothelium. We investigated plasma total TFPI, antiphospholipid antibodies, and some other coagulation and fibrinolytic system parameters in 30 patients with Behçet's disease and 15 controls by the enzyme-linked immunosorbent assay method. TFPI levels were significantly higher in the Behçet's group (119 +/- 57.5 ng/ml) compared with the control group (74.8 +/- 31.5) (P < 0.009). We also noted a statistical significance in TFPI levels between patients with active disease (n:16) (139 +/- 55) and patients without activation (n:14) (96 +/- 53) (P < 0.03), whereas inactive patients lacked any significance when compared with the control group (P < 0.29). Other parameters disclosed no statistical significance between patients and control group except for elevated fibrinogen and plasminogen activator inhibitor-1 levels in the patient group (P < 0.003). Increased levels of TFPI may reflect a defensive mechanism like in other diseases characterized by thrombotic tendency and represent a parameter of disease activity.

Potential new therapeutic options in Behçet's syndrome

Behçet's syndrome is a multisystem disorder that causes orogenital ulceration, skin lesions and intraocular inflammation with uveitis and retinal vasculitis. A proportion of affected individuals also develop vascular and central nervous system manifestations, with significant morbidity and mortality. Although the aetiopathogenesis of Behçet's syndrome is poorly understood, the condition is considered to be driven, at least in part, by autoimmune mechanisms. Conventional therapy relies on available anti-inflammatory and immunomodulatory agents, and, in view of the paucity of controlled clinical trials, it is to a large extent empirical. Oral ulcers can often be treated by topical application of corticosteroids. In addition to corticosteroids, agents used to treat ocular inflammation and significant systemic manifestations include colchicine, thalidomide, azathioprine, mycophenolate mofetil, cyclosporin, tacrolimus, cyclophosphamide and chlorambucil. The response to these agents is variable and there is a distinct need for more effective rational treatment. Over the last decade, a number of open studies have produced promising results using recombinant interferon-alpha preparations. Evaluating, in a methodical manner, the other new biological agents that are becoming available for the treatment of inflammatory diseases offers great promise, not only for effective management but also for providing insights into aetiopathogenesis.

The multiple faces of Behçet's disease and its aetiological factors

Behçet's disease (BD) is a chronic, inflammatory multisystemic condition of unknown aetiology. It is clinically characterized by recurrent orogenital ulcerations and skin eruptions; ocular manifestations; arthritis; vasculitis and in some cases neurological and large vessel involvement. Aetiology has not been defined, but genetic, environmental, viral, bacterial and immunological factors have been proposed as causative agents. Treatment includes colchicine, thalidomide, steroids and immunosuppressive agents and it is based on the severity of systemic manifestations, such as central nervous system involvement, arterial aneurysms and thrombosis of the major veins. Mortality is related to major system involvement. In this article the different clinical features, the multiple faces of BD and a list of currently suspected aetiological factors of the disease are discussed, and treatment modalities summarized.

Vascular endothelial function and oxidative stress mechanisms in patients with Behçet's syndrome

OBJECTIVES

We sought to test the hypothesis that vascular endothelial function is impaired in Behçet's syndrome and reflects increased levels of oxidative stress.

BACKGROUND

Behçet's syndrome is a multisystem inflammatory disorder commonly complicated by vascular thrombosis and arterial aneurysm formation. The precise mechanisms underlying vascular disease in Behçet's syndrome are not known.

METHODS

We studied 19 patients with Behçet's syndrome (18 to 50 years old, 9 men) and 21 healthy volunteers (18 to 50 years old, 10 men). Brachial artery flow-mediated dilation (endothelium-dependent), and nitroglycerin (NTG)-induced dilation (endothelium-independent) were measured. To investigate oxidative stress mechanisms, vascular studies were repeated 1 h after administration of vitamin C (1 g, intravenous) in 12 patients and 12 control subjects.

RESULTS

Flow-mediated dilation was reduced in patients with Behcet's syndrome as compared with control subjects (0.7 +/- 0.9% vs. 5.7 +/- 0.9%, p = 0.001). In contrast, there were no significant differences in the brachial artery diameter (4.2 +/- 0.2 vs. 4.0 +/- 0.2 mm, p = 0.47) or NTG-induced dilation (19.7 +/- 1.9% vs. 19.7 +/- 1.2%, p = 0.98). In regression analysis, Behçet's syndrome was associated with impaired flow-mediated dilation independent of age, gender, brachial artery diameter, blood pressure, cholesterol and glucose. Vitamin C increased flow-mediated dilation in Behçet's syndrome (0.2 +/- 0.7% to 3.5 +/- 1.0%, p = 0.002), but not in control subjects (4.3 +/- 0.6% to 4.7 +/- 0.4%, p = 0.51). In both groups, NTG-induced dilation and brachial artery diameter were unchanged after vitamin C treatment.

CONCLUSIONS

Vascular endothelial function is impaired in Behcet's syndrome and can be rapidly improved by vitamin C treatment. Our results support a role for oxidative stress in the pathophysiology of Behçet's syndrome and provide a rationale for therapeutic studies aimed at reducing vascular complications in this disorder.

Macular ischaemia in Behçet's disease

PURPOSE

To report macular ischaemia and visual loss in patients with panuveitis due to Behçet's disease.

METHODS

We describe macular ischaemia, a rare finding, in 3 eyes of 3 patients with panuveitis who were diagnosed and treated as having Behçet's disease. The patients underwent fundus fluorescein angiography (FFA) using a digital imaging system and were treated with topical and oral steroids and cyclosporine in 2 cases, and with added azathioprine in the third case.

RESULTS

The 3 eyes showed macular ischaemia associated with peripheral retinal vasculitis on FFA and control of inflammation was achieved in all cases. After an average of 2 years follow-up, visual acuity and macular ischaemia improved in 2 eyes, while no recovery was seen in the third.

CONCLUSION

The presence of macular ischaemia on FFA in Behçet's disease is a predictor of poor visual outcome. Macular ischaemia may show partial recovery with the treatment of the disease.

Fatal pulmonary artery thrombosis in a patient with Behçet's disease, activated protein C resistance and hyperhomocystinemia

Behçet's disease (BD) is known for its tendency for thromboembolism, which is thought to be due to vascular injury. The important role of inherited thrombophilias is now becoming increasingly clear. However, conflicting data exist in terms of the contribution of these factors to the thrombotic risk in BD. In this case report, we describe a patient with BD who presented with severe cor pulmonale due to recurrent chronic venous thromboembolism and pulmonary artery thrombosis. The biochemical evaluation revealed that the patient was homozygotic for the factor V Leiden (R506Q) mutation and had increased levels of homocysteine. His condition deteriorated despite adequate anticoagulation treatment, and he died suddenly after 7 months of follow-up. We assume that the presence of thrombophilic risk factors augments and synergizes with the hypercoagulable state already existing in BD, leading to fatal thrombosis in this patient.

Haemostasis in patients with Behçet's disease

AIM

to determine whether Behçet's disease affects haemostatic function.

SETTING

University Hospital, Turkey.

PATIENTS

one hundred and twenty-seven consecutive patients with Behçet's disease, 34 of whom with a history of vascular involvement.

METHODS

prothrombin fragment 1+2 tissue plasminogen activator, protein S and C, antithrombin, fibrinogen, von Willebrand factor, thrombomodulin and prothrombin time (PT) were measured in patient plasma.

RESULTS

soluble thrombomodulin was significantly lower and von Willebrand factor (vWF) and tissue plasminogen activator (tPA) significantly higher in Behçet's patients. Patients with vascular involvement showed the highest levels of vWF and tPA. There was no activation of coagulation, not even in patients with an active disease at the time of sampling.

CONCLUSION

there were indirect signs of endothelial activity or damage, particularly in patients with vascular involvement. Coagulation was not activated.

Factor V Leiden mutation is associated with ocular involvement in Behçet disease

PURPOSE

Behçet disease is a systemic disease of young adults characterized by venous occlusion in both the deep venous and retinal circulations. In severe ocular disease, blindness may occur despite immunosuppressive treatment. The most common inherited risk factor for the development of idiopathic venous thrombosis is the presence of the Factor V (FV Leiden) mutation, which confers resistance to activated protein C. The association of FV Leiden with Behçet disease has been reported, but its influence on ocular disease is not known. We therefore investigated the prevalence of this mutation in patients with Behçet disease to determine its contribution to the presence and severity of ocular disease.

METHODS

One hundred and six Middle Eastern patients satisfying international criteria, and 120 healthy control subjects without a history of venous thrombosis were included in the study, and patients underwent standard examination by two ophthalmologists with an interest in Behçet disease. Genomic DNA was extracted from peripheral blood leukocytes and screened for the FV Leiden mutation with the polymerase chain reaction method with sequence-specific primers (PCR-SSP).

RESULTS

FV Leiden was detected in 19% (23/120) of the control population compared with 27% (29/106) of all patients with Behçet disease (P = .13). However, among patients with Behçet disease who had ocular disease (75/106), the prevalence of FV Leiden was significantly higher (32%) than it was in control subjects (P = .04). Furthermore, ocular patients with Behçet disease in whom retinal occlusive disease was observed (25/75) had the highest expression of FV Leiden (44%).

CONCLUSIONS

These data suggest that FV Leiden may be an additional risk factor for the development of ocular disease and, in particular, retinal vaso-occlusion, and it may contribute to the poor visual outcome in these patients.

Arterial thrombosis leading to intestinal infarction in a patient with Behçet's disease associated with protein C deficiency

Behçet's disease may be a possible cause of both occlusive and aneurysmal arterial involvement as well as recurrent venous thrombosis. A case of Behçet's disease complicated with vascular involvement leading to intestinal infarction is presented. A 41-yr-old man suffering from Behçet's disease for 15 yr presented with a 2-day history of severe abdominal pain and bloody diarrhea. Intestinal infarction secondary to thrombosis of the superior mesenteric artery had been diagnosed during surgical exploration 3 yr previously. He was started on anticoagulation with nutritional support. The patient was readmitted with severe diarrhea and malabsorption symptoms 3 yr after intestinal resection. A thrombus located in the posterior wall of the infrarenal portion of aorta was detected by aortography and ultrasonography. Although thrombosis is a relatively common complication of Behçet's disease caused by vasculitis, protein C deficiency, which is a pertinent laboratory finding in this case, might be a secondary factor in the thrombotic event. This is the first case reported of mesenteric artery thrombosis leading to bowel infarction and abdominal aorta thrombosis associated with protein C deficiency.

Serum of Behçet's disease enhances superoxide production of normal neutrophils

Using an MCLA-dependent chemiluminescence technique, we evaluated superoxide production by neutrophils isolated from 7 patients with Behçet's disease. After stimulation by phorbol myristate acetate, N-formyl-methionyl-leucyl-phenylalanine or opsonized zymosan, neutrophils from the patients produced significantly more superoxide than those from 20 controls. Pretreatment of control neutrophils with serum prominently enhanced superoxide production, and serum from Behçet's disease patients had a significantly greater effect than that from controls. These findings suggest that serum from patients with Behçet disease contains the priming factor(s) that can enhance enhanced superoxide production by neutrophils in response to stimulation.

Behçet's syndrome presenting with peripheral arterial aneurysms

A case of Behçet's syndrome is described presenting with several peripheral arterial aneurysms. The diagnostic criteria are discussed and the need for increased vigilance of this disease is stressed due to an increasing number of immigrants.

Protein S deficiency and antibodies to protein S in patients with Behçet's disease

Thrombosis occurs in 20 to 30% of patients with Behçet's disease (BD). Most of the reported hemostatic abnormalities are related to the inflammatory syndrome. We have assessed the activity of antithrombin III, protein C and protein S (PS), in 30 patients with BD and in 30 healthy controls. Thrombosis antecedents were found in 16 patients. Antithrombin III and protein C were within the normal range, however free PS and PSactivity were significantly decreased in patients as compared to control group. PS deficiency detected in eight patients, was associated to thrombosis in 6 of them. No correlation was found between free PS/total PS ratio and C4bBP levels. Antibodies to PS were screened by ELISA and were present in 6 patients, associated to PS deficiency in 4, and to thrombosis antecedents in 5 cases. PS deficiency was transient in two patients, associated to a persistent antiPS in one of them. These findings suggest that auto-immune acquired PS deficiency may be involved in the pathogenesis of thrombotic events in BD.