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1.  Antiphospholipid antibodies predict imminent vascular events independently from other risk factors in a prospective cohort 
Thrombosis and haemostasis  2009;101(1):100-107.
Antiphospholipid antibodies (aPL) are associated with vascular events, but the magnitude of this risk, alone, or in combination with other atherogenic and thrombophilic risk factors, remains unclear. A prospective cohort of 415 persons was studied for arterial and venous events (AE and VE) over a median time of 7.4 years. aPL and coagulation abnormalities were measured upon beginning of the study and annually for the first four years. Within the cohort, a nested case-control study was conducted to investigate the role of endothelial and inflammatory markers in predicting new vascular events. Forty-five individuals had new vascular events: 18 occurred during the first year of follow-up. The proportion of event-free survivors at eight years was 90% (95%CI = 87%, 94%) for aPL-negative and 72% (60%, 85%) for aPL-positive individuals, respectively. Predictors for new AE were previous AE (HR=5.7 [2.7, 12.0]), diabetes (5.6 [2.4, 13.2]), aPL positivity (2.6 ([1.2, 5.9]), and age (1.04 [1.01, 1.07]). New VE were predicted by previous VE (6.1 [1.9, 19.9]), anti-β2-glyco-protein I (aβ2GPI) positivity (5.8 [1.4, 24.1]), activated protein C resistance (APCR) (4.1 [1.1, 15.1]), and gender (3.7 [1.1, 12.9]). In the nested case-control study, similar predictors were observed for AE, while abnormal APCR (OR=5.5 [1.1, 26.6]) and elevated von Willebrand factor (vWF) (OR=5.0 [1.2, 19.8]) best predicted VE. We demonstrate that aPL independently predict new vascular events and discriminate between individuals with and without events in the first two years of follow-up, indicating that aPL are associated with a short-term risk of developing new and recurrent vascular events.
PMCID: PMC3435426  PMID: 19132195 CAMSID: cams2314
Antiphospholipid antibodies; thrombosis; anti-beta2-glycoprotein I; activated protein C resistance; von Willebrand factor
2.  High Antiphospholipid Antibody Levels are Associated with Statin Use and May Reflect Chronic Endothelial Damage in Non-Autoimmune Thrombosis: cross-sectional study 
Journal of clinical pathology  2012;65(6):551-556.
Persistently elevated antiphospholipid antibodies (aPL Ab) and positive lupus anticoagulant (LAC) are associated with an increased risk of thrombosis. Our objective was to explore whether aPL Ab and/or LAC positivity were associated with the traditional risk factors for thrombosis or with medication use in patients without autoimmune diseases hospitalized with arterial or venous thrombosis.
Cross-sectional study
Montefiore Medical Center, a large urban tertiary care center
Two hundred and seventy patients (93 with deep vein thrombosis (DVT) or pulmonary embolism (PE), and 177 with non-hemorrhagic stroke (CVA)) admitted between January 2006 and December 2010 with a discharge diagnosis of either DVT, PE or CVA, who had LAC and aPL Abs measured within six months from their index admission. We excluded patients with lupus or antiphospholipid syndrome.
Main Outcome Measures
The main dependant variable was aPL Ab ≥ 40 units (aPL Ab+) and/or LAC+. Independent variables: traditional thrombosis risk factors, statin use, aspirin use, and warfarin use.
Thirty one (11%) patients were LAC+ and/or aPL Ab+ (aPL/LAC+). None of the traditional risk factors at the time of DVT/PE/CVA was associated with aPL/LAC+. Current statin use was associated with an OR of 3.2 (95% CI 1.3, 7.9, p = 0.01) of aPL/LAC+, adjusted for age, ethnicity and gender. Aspirin or warfarin use was not associated with aPL Ab levels.
If statin therapy reflects the history of prior hyperlipidemia, high levels of aPL Abs may be a marker for prior endothelial damage caused by hyperlipidemia.
PMCID: PMC3760969  PMID: 22389514
Antiphospholipid antibodies; statins; endothelial damage; thrombosis
3.  Thromboembolic risk in patients with high titre anticardiolipin and multiple antiphospholipid antibodies 
Thrombosis and haemostasis  2003;90(1):108-115.
Asymptomatic antiphospholipid antibody (aPL) carriers with high risk for thrombosis may benefit from preventive anticoagulation.
It was our objective to test whether the risk of thrombosis increases with: 1) increasing titres of anticardiolipin antibodies (aCL) after adjustment for other cardiovascular risk factors and 2) the number of aPL detected.
In a cross-sectional study, blood was collected from clinics in two teaching hospitals. The study included 208 individuals suspected of having an aPL and 208 age- and sex-matched controls having blood drawn for a complete blood count.
Clinical variables included history of previous arterial (ATE) or venous (VTE) thrombotic events, traditional risk factors for cardiovascular disease, and systemic lupus erythematosus (SLE). Laboratory variables included IgG/IgM aCL, lupus anticoagulant, and IgG/IgM anti-β2-glycoprotein I.
Mean age was 46.5 years and 83% were female. Seventy-five of the 416 participants had ≥ 1 aPL, and 69 had confirmed ≥ 1 ATE or VTE. Family history was positive in 48% of participants, smoking in 28%, hypertension in 16%, diabetes in 6%, and SLE in 20%. A 10-unit increase in aCL IgG titre was associated with an odds ratio (OR) [95% CI] of 1.07 [1.01–1.13] for ATE and 1.06 [1.02 – 1.11] for VTE. The odds of a previous thrombosis increased with each additional aPL detected: 1.5 [0.93–2.3] for ATE and 1.7 [1.1–2.5] for VTE.
These results indicate that increased titres of aCL and multiple aPL were associated with an increased risk of a previous thrombotic event.
PMCID: PMC3482244  PMID: 12876633 CAMSID: cams2357
Antiphospholipid syndrome; antiphospholipid antibodies; anti-cardiolipin antibody; thrombosis
4.  Prevalence of thrombophilic mutations in patients with unprovoked thromboembolic disease. A comparative analysis regarding arterial and venous disease 
Hippokratia  2012;16(3):250-255.
Background: Thromboembolic disease (TED) represents one of the main reasons of morbitity and mortality in Western World. Venous and arterial thrombotic disorders have long been viewed as separate pathophysiological entities. However, in recent times the separate nature of arterial and venous thrombotic events has been challenged. Although inherited thrombophilia’s predominant clinical manifestation is venous thrombosis, its contribution to arterial thrombosis remains controversial. Purpose  of  the  study  was  to  evaluate  the  prevalence  of  the  most common  thrombophilic  mutations, FV Leiden G1691A-FVL and FII G20210A-PTM and to assess  the  differences between venous, arterial and mixed thrombotic events. Testing  for polymorphism MTHFR C677T and  antithrombin,  protein  C  and  protein  S was also performed. Correlations with  dyslipidemia, smoking, obesity, homocysteine and antiphospholipid antibodies were made.
Methods: 515 patients with unprovoked TED, 263 males, median age 44 years, were studied. Patients were divided into three groups: 258 with venous thrombosis (group A), 239 with arterial (group B) and 18 with mixed episodes (group C). All patients were interviewed regarding family history of TED, origin, smoking and dyslipidemia. Body mass index (BMI) had been calculated. Molecular assessment of the FVL, PTM and MTHFR C677T was performed. Antithrombin, protein C, protein S, APCR, homocysteine, antiphospholipid antibodies and lipid profile were also measured.
Results: The population studied was homogenous among three groups as regards age (p=0.943), lipid profile (p=0.271), BMI (p=0.506), homocysteine (p=0.177), antiphospholipid antibodies (p=0.576), and positive family history (p=0.099). There was no difference in the prevalence of FVL between venous and arterial disease (p=0.440). Significant correlation of PTM with venous TED was found (p=0.001). The number of positive and negative for MTHFR presented statistically significant difference with a support in arterial disease (p=0.05). Moreover, a 2-fold increase in the risk of venous thrombosis in FVL positive patients (odds ratio: 2.153) and a positive correlation of homocysteine levels with MTHFR C677T (p<0.001) was found.
Conclusions: Correlation of PTM with venous thrombosis was established. Analysis showed no difference in prevalence of FVL between venous and arterial thrombosis, indicating that FVL might be a predisposing factor for arterial disease. A significant increase in MTHFR C677T prevalence in arterial disease was found. In conclusion, young patients with unprovoked arterial disease should undergo evaluation for thrombophilic genes. Identification of these mutations is important in the overall assessment and management of patients at high risk. Findings will influence the decisions of stratified approaches for antithrombotic therapy either primary or secondary thromboprophylaxis, the duration of therapy, the potential for avoiding clinical thrombosis by risk factor modification and the genetic counselling of family members. However, further studies are needed to clarify the nature of the association regarding venous and arterial thrombotic events.
PMCID: PMC3738733  PMID: 23935293
thrombophilic mutations; unprovoked thromboembolic disease; arterial thromboembolic disease; venous thromboembolic disease
5.  Antiphospholipid antibodies (aPL) in systemic lupus erythematosus. Are they specific tools for the diagnosis of aPL syndrome? 
Annals of the Rheumatic Diseases  1994;53(2):140-142.
OBJECTIVE--Antiphospholipid antibody (aPL) specificity for aPL-related events was evaluated in systemic lupus erythematosus (SLE). METHODS--A study was carried out on 105 patients affected with SLE comparing the prevalence of lupus anticoagulant (LA) and IgG and IgM anticardiolipin antibodies (aCL) between patients with and without features of antiphospholipid syndrome (APS). Antiphospholipid antibody profile was subsequently evaluated in the aPL positive patients with and without aPL-related events, thus excluding the patients with complications of APS possibly due to factors other than aPL. RESULTS--LA showed a strong association with thrombosis and livedo reticularis, and IgG aCL with thrombosis and neurological disorders, while no clinical features were associated with IgM aCL. A considerable number of aPL positive patients with no aPL-related manifestations was also observed, suggesting the low specificity of aPL assays (54.4%). When studying the 60 aPL positive patients, LA was specific (91.3%) for the diagnosis of aPL-related thrombosis, whereas aCL were not specific, although IgG aCL mean levels were higher in patients with arterial thrombosis than in those without APS features. CONCLUSIONS--LA but not aCL positivity is a specific tool for the diagnosis of thrombotic complications due to aPL in SLE.
PMCID: PMC1005268  PMID: 8129460
6.  Value of Isolated IgA anti-β2GPI Positivity in the Diagnosis of the Antiphospholipid Syndrome 
Arthritis and rheumatism  2013;65(12):3186-3193.
To examine the prevalence of isolated IgA anti-β2Glycoprotein I (anti-β2GPI) positivity and the association of these antibodies, and a subgroup that bind specifically to domain IV/V of β2GPI, with clinical manifestations of the Antiphospholipid Syndrome (APS) in three patients groups. The pathogenicity of IgA anti-β2GPI was also evaluated in a mouse model of thrombosis.
Patients with systemic lupus erythematosus (SLE) from a multiethnic, multicenter cohort (LUpus in MInorities, NAture versus nurture [LUMINA]) (n=558), patients with SLE from the Hopkins Lupus Cohort (n=215), and serum samples referred to the Antiphospholipid Standardization Laboratory (APLS) (n=5,098) were evaluated. IgA anti-β2GPI titers and binding to domain IV/V of β2GPI were examined by enzyme-linked immunosorbent assay (ELISA). CD1 mice were inoculated with purified IgA anti- β2GPI antibodies, and surgical procedures and ELISAs were performed to evaluate thrombus development and tissue factor (TF) activity.
A total of 198 patients were found to be positive for IgA anti-β2GPI isotype, and 57 patients were positive exclusively for IgA anti-β2GPI antibodies. Of these, 13 of 23 patients (56.5%) in the LUMINA cohort, 17 of 17 patients (100%) in the Hopkins cohort, and 10 of 17 patients (58.9%) referred to APLS had at least one APS-related clinical manifestation. Fifty-four percent of all the IgA anti-β2GPI positive serum samples reacted with domain IV/V of anti-β2GPI, and 77% of those had clinical features of APS. Isolated IgA anti-β2GPI positivity was associated with an increased risk for arterial thrombosis (p<0.001), venous thrombosis (p=0.015) and all thrombosis (p<0.001). The association between isolated IgA anti-β2GPI and arterial thrombosis (p=0.0003) and all thrombosis (p=0.0003) remained significant after adjusting for other risk factors for thrombosis. In vivo mouse studies demonstrated that IgA anti-β2GPI antibodies induced significantly larger thrombi and higher TF levels compared to controls.
Isolated IgA anti-β2GPI positive titers may identify additional patients with clinical features of APS. Testing for these antibodies when other antiphospholipid (aPL) tests are negative and APS is suspected is recommended. IgA anti-β2GPI antibodies directed to domain IV/V of β2GPI represent an important subgroup of clinically relevant antiphospholipids.
PMCID: PMC4048705  PMID: 23983008
7.  Prevention of fetal loss in experimental antiphospholipid syndrome by in vivo administration of recombinant interleukin-3. 
Journal of Clinical Investigation  1993;91(4):1834-1837.
Antiphospholipid antibodies are strongly associated with arterial and venous thrombosis and with fetal loss. Recently an experimental model for antiphospholipid syndrome (APLS) was established in our laboratory. In this model, mice are immunized passively or actively with anticardiolipin antibodies and acquire the syndrome, which is characterized by prolonged activated partial thromboplastin time (APTT), thrombocytopenia, low fecundity rate, and fetal loss. In a normal process of pregnancy, lymphokines affect fetal implantation and development. Cytokines from the colony stimulating factor family, like GM-CSF and IL-3, were shown to be positive signals for implantation and to promote placental development and fetal growth. Given our preliminary findings of low IL-3 in mice with APLS and the efficacy of IL-3 in preventing fetal loss in a strain of mice prone to fetal resorption, our aim in the present study was to examine the effect of murine recombinant IL-3 (mrIL-3) on pregnant mice induced with experimental APLS. Mice were passively transfused to the tail vein, 24 h following mating, with anticardiolipin antibodies. The mice were divided into two groups: one group was injected intraperitoneally with mrIL-3 on days 6.5, 8.5, and 10.5 after mating, while the control group was injected with PBS. When the mice were killed on day 15 of pregnancy a 32% +/- 4.2 resorption rate was observed in the anti-cardiolipin-immunized group, which was reduced to 4% +/- 0.3 following treatment with mrIL-3. The thrombocytopenia associated with the experimental APLS was also corrected following lymphokine administration. IL-3 may be effective in prevention of recurrent fetal loss in APLS.
PMCID: PMC288166  PMID: 8473523
8.  Patent foramen ovale, cardiac valve thickening and antiphospholipid antibodies as risk factors for subsequent vascular events: The PICSS-APASS Study 
(1) Estimate risk of recurrent stroke/TIA/death in the subgroup of the Patent foramen ovale in the Cryptogenic Stroke Study (PICSS) cohort with patent foramen ovale (PFO) and antiphospholipid antibodies (aPL) and (2) Estimate risk of recurrent stroke/TIA/death in aPL positive patients who have thickened left-sided heart valves (VaT).
PFO is associated with cryptogenic ischemic stroke. Also, the presence of aPL is associated with ischemic cerebrovascular disease.
Combined data from 2 major sub studies of the Warfarin Aspirin Recurrent Stroke Trial (WARSS) were evaluated. PICSS subjects were included if they were enrolled in the Antiphospholipid Antibodies and Stroke Study (APASS) and had a baseline aPL test (lupus anticoagulant, anticardiolipin antibodies, or both) within one month of the stroke. All patients in PICSS underwent transesophageal echocardiography for PFO as well as VaT, which was performed blinded to aPL status and treatment arm (325mg/d aspirin or adjusted dose warfarin, target INR 1.4–2.8). The primary outcome event was the 2-year risk of recurrent stroke/TIA/death and was evaluated using Cox proportional hazards model. As there was no treatment effect, warfarin and aspirin groups were combined to increase power. For the combined endpoint, power to detect a HR of 2 was 47.8% for the PFO and aPL positive group, and 75.3% for the valve thickening and aPL positive group, assuming two-sided type I error of 0.05
525 subjects were tested for the combined presence of PFO and aPL and were available for evaluation. The primary outcome event rate was 23.9% (HR 1.39, 95% CI 0.75–2.59) in the PFO positive/aPL positive group, compared to 13.9% (HR 0.83, 95% CI 0.44–1.56) in the PFO positive/aPL negative group and 19.9% (HR 1.16 95% CI 0.68–1.90) in the PFO negative/aPL positive group.
545 subjects tested for combined presence of aPL and left sided cardiac VaT were available for evaluation. The primary event rate was 22.6% (HR1.65, 95% CI 0.88–3.09) in the VaT positive/aPL positive group, compared to 19.4% (HR 1.50, 95% CI 0.82–2.75) in the VaT positive/aPL negative group and 20.2% (HR 1.63, 95% CI 0.81–3.25) in the VaT negative /aPL positive group.
The combined presence of aPL with either a PFO or with left sided cardiac VaT did not significantly increase risk of subsequent cerebrovascular events in this PICCS/APASS cohort of patients.
PMCID: PMC2761081  PMID: 19498198
patent foramen ovale; anti-phospholipid antibodies; cardiac valve thickening; stroke recurrence risk; stroke risk factors; Risk Factors
9.  Hydroxychloroquine Use is Associated with Lower Odds of Persistently Positive Antiphospholipid Antibodies and/or Lupus Anticoagulant in SLE 
The Journal of rheumatology  2012;40(1):30-33.
Antiphospholipid antibodies (aPL Abs) play an active role in the pathogenesis of the antiphospholipid syndrome (APLS). Primary prevention in APLS may be aimed at decreasing existing elevated aPL Ab levels, or preventing high aPL titers and/or lupus anticoagulant (LAC) from developing in the first place. Hydroxychloroquine (HCQ) has been shown to decrease aPL titers in laboratory studies, and to decrease thrombosis risk in systemic lupus erythematosus (SLE) patients in retrospective studies. We investigated an association between HCQ use and persistent aPL Abs and/or LAC in SLE.
We identified all patients over 21 years old with SLE, from an urban tertiary care center, who had aPL Abs and LAC measured on at least 2 occasions, at least 12 weeks apart. We defined the presence of persistent LAC+ and/or at least one aPL Ab ≥ 40 units (IgA, IgG or IgM) as the main outcome variable.
Among 90 patients included in the study, 17 (19%) had persistent LAC+ and/or at least one aPL Ab ≥ 40 units. HCQ use was associated with significantly lower odds of having persistent LAC+ and/or aPL Abs ≥ 40 U, OR 0.21 (95% CI 0.05, 0.79) p=0.02, adjusted for age, ethnicity, and gender.
This is the first study to show that HCQ use is associated with lower odds of having persistently positive LAC and/or aPL Abs. Data from this study provides a basis for the design of future prospective studies investigating the role of HCQ in primary and secondary prevention of APLS.
PMCID: PMC3768146  PMID: 22859353
Lupus Erythematosus, Systemic; Antiphospholipid Antibodies; Lupus Anticoagulant; Hydroxychloroquine
10.  Antiphospholipid syndrome; its implication in cardiovascular diseases: a review 
Antiphospholipid syndrome (APLS) is a rare syndrome mainly characterized by several hyper-coagulable complications and therefore, implicated in the operated cardiac surgery patient. APLS comprises clinical features such as arterial or venous thromboses, valve disease, coronary artery disease, intracardiac thrombus formation, pulmonary hypertension and dilated cardiomyopathy. The most commonly affected valve is the mitral, followed by the aortic and tricuspid valve. For APLS diagnosis essential is the detection of so-called antiphospholipid antibodies (aPL) as anticardiolipin antibodies (aCL) or lupus anticoagulant (LA). Minor alterations in the anticoagulation, infection, and surgical stress may trigger widespread thrombosis. The incidence of thrombosis is highest during the following perioperative periods: preoperatively during the withdrawal of warfarin, postoperatively during the period of hypercoagulability despite warfarin or heparin therapy, or postoperatively before adequate anticoagulation achievement. Cardiac valvular pathology includes irregular thickening of the valve leaflets due to deposition of immune complexes that may lead to vegetations and valve dysfunction; a significant risk factor for stroke. Patients with APLS are at increased risk for thrombosis and adequate anticoagulation is of vital importance during cardiopulmonary bypass (CPB). A successful outcome requires multidisciplinary management in order to prevent thrombotic or bleeding complications and to manage perioperative anticoagulation. More work and reporting on anticoagulation management and adjuvant therapy in patients with APLS during extracorporeal circulation are necessary.
PMCID: PMC2987921  PMID: 21047408
11.  Platelet Activation and Anti-Phospholipid Antibodies Collaborate in the Activation of the Complement System on Platelets in Systemic Lupus Erythematosus 
PLoS ONE  2014;9(6):e99386.
Anti-phospholipid (aPL) antibodies are important contributors to development of thrombosis in patients with the autoimmune rheumatic disease systemic lupus erythematosus (SLE). The underlying mechanism of aPL antibody-mediated thrombosis is not fully understood but existing data suggest that platelets and the complement system are key components. Complement activation on platelets is seen in SLE patients, especially in patients with aPL antibodies, and has been related to venous thrombosis and stroke. The aim of this study was to investigate if aPL antibodies could support classical pathway activation on platelets in vitro as well as in SLE patients. Furthermore, we investigated if complement deposition on platelets was associated with vascular events, either arterial or venous, when the data had been adjusted for traditional cardiovascular risk factors. Finally, we analyzed if platelet complement deposition, both C1q and C4d, was specific for SLE. We found that aPL antibodies supported C4d deposition on platelets in vitro as well as in SLE patients (p = 0.001 and p<0.05, respectively). Complement deposition on platelets was increased in SLE patients when compared with healthy individuals (p<0.0001). However, high levels of C4d deposition and a pronounced C1q deposition were also seen in patients with rheumatoid arthritis and systemic sclerosis. In SLE, C4d deposition on platelets was associated with platelet activation, complement consumption, disease activity and venous (OR = 5.3, p = 0.02), but not arterial, thrombosis, observations which were independent of traditional cardiovascular risk factors. In conclusion, several mechanisms operate in SLE to amplify platelet complement deposition, of which aPL antibodies and platelet activation were identified as important contributors in this investigation. Complement deposition on platelets was identified as a marker of venous, but not arterial thrombosis, in SLE patients independently of traditional risk factors and aPL antibodies. Further studies are needed to elucidate the role of complement deposition on platelets in development of venous thrombosis.
PMCID: PMC4055750  PMID: 24922069
12.  Review on Effectiveness of Primary Prophylaxis in aPLs with and without Risk Factors for Thrombosis: Efficacy and Safety 
ISRN Rheumatology  2014;2014:348726.
Context. Antiphospholipid antibodies syndrome is an autoimmune disorder that is characterized by the association between presence of antiphospholipid antibodies and risk of thrombosis and/or pregnancy morbidity. Objectives. To systematically review the evidence for primary prophylaxis in patients with antiphospholipids antibodies syndrome or APS with or without other traditional risk factors of thrombosis when they did not have any thrombotic event yet. Methods. PubMed, the Cochrane Library, and Allied Health Literature were searched for studies that examined the efficacy and safety of primary prophylaxis in aPL patients from 1990 to February 2013. We examined literature looking at patients with aPLs with other risk factors for thrombosis and aPLs with no additional risk factors for thrombosis. Conclusion. We concluded that, in patients with aPLs, primary prophylaxes with HCQ and aspirin have been observed to reduce the frequency of thrombotic events in the case of asymptomatic aPL-positive patients with SLE. We also in this study concluded that LDA was effective in patients with autoimmune diseases. Independent cardiovascular risk factors include autoimmune defects such as SLE, rheumatoid arthritis, and atherosclerosis, where overall venous thrombosis will be induced by systemic inflammation. This review concludes that HCQ is an effective primary approach when compared to aspirin.
PMCID: PMC4040209  PMID: 24944829
13.  Association of Autoantibodies to Heat-Shock Protein 60 With Arterial Vascular Events in Patients With Antiphospholipid Antibodies 
Arthritis and rheumatism  2011;63(8):2416-2424.
Anti–heat shock protein 60 autoantibodies (anti-Hsp60) are associated with cardiovascular disease and are known to affect endothelial cells in vitro, and we have recently shown that anti-Hsp60 promote thrombosis in a murine model of arterial injury. Based on those findings, we undertook the present study to investigate the hypothesis that the presence of anti-Hsp60, alone or in combination with other thrombogenic risk factors, is associated with an elevated risk of vascular events.
The study population was derived from 3 ongoing cohort studies: 2 independent systemic lupus erythematosus (SLE) registries and 1 cohort comprising SLE patients and non-SLE patients. Data from a total of 402 participants were captured; 199 of these participants had had confirmed vascular events (arterial vascular events in 102, venous vascular events in 76, and both arterial and venous vascular events in 21). Anti-Hsp60 were detected by enzyme-linked immunoassay, and association with vascular events was assessed by regression analysis.
Multiple regression analysis revealed that arterial vascular events were associated with male sex, age, and hypertension. Analyses of the vascular events according to their origin showed an association of anti-Hsp60 with arterial vascular events (odds ratio 2.26 [95% confidence interval 1.13–4.52]), but not with venous vascular events. Anti-Hsp60 increased the risk of arterial vascular events (odds ratio 5.54 [95% confidence interval 1.89–16.25]) in antiphospholipid antibody (aPL)–positive, but not aPL-negative, individuals.
We demonstrate that anti-Hsp60 are associated with an increased risk of arterial vascular events, but not venous vascular events, in aPL-positive individuals. These data suggest that anti-Hsp60 may serve as a useful biomarker to distinguish risk of arterial and venous vascular events in patients with aPL.
PMCID: PMC3465366  PMID: 21506099 CAMSID: cams2354
14.  Antiphospholipid antibodies in black south africans with hiv and acute coronary syndromes: prevalence and clinical correlates 
BMC Research Notes  2011;4:379.
HIV infection is associated with a high prevalence of antiphospholipid antibodies (aPL) and increased thrombotic events but the aetiopathogenic link between the two is unclear.
Prospective single centre study from Soweto, South Africa, comparing the prevalence of aPL in highly active anti-retroviral therapy (HAART) naïve HIV positive and negative patients presenting with Acute Coronary Syndromes (ACS). Between March 2004 and February 2008, 30 consecutive black South African HIV patients with ACS were compared to 30 black HIV negative patients with ACS. The HIV patients were younger (43 ± 7 vs. 54 ± 13, p = 0.004) and besides smoking (73% vs. 33%, p = 0.002) and lower HDL levels (0.8 ± 0.3 vs. 1.1 ± 0.4, p = 0.001) had fewer risk factors than the control group. HIV patients had a higher prevalence of anticardiolipin (aCL) IgG (47% vs. 10%, p = 0.003) and anti-prothrombin (aPT) IgG antibodies (87% vs. 21%, p < 0.001) but there was no difference in the prevalence of the antiphospholipid syndrome (44% vs. 24%, p = N/S) and aPL were not predictive of clinical or angiographic outcomes.
Treatment naïve black South African HIV patients with ACS are younger with fewer traditional coronary risk factors than HIV negative patients but have a higher prevalence and different expression of aPL which is likely to be an epiphenomenon of the HIV infection rather than causally linked to thrombosis and the pathogenesis of ACS.
PMCID: PMC3199261  PMID: 21970576
15.  Antiphospholipid Antibodies and Multiple Organ Failure in Critically Ill Cancer Patients 
Clinics (Sao Paulo, Brazil)  2009;64(2):79-82.
To describe the clinical outcomes and thrombotic events in a series of critically ill cancer patients positive for antiphospholipid (aPL) antibodies.
Retrospective case series study.
Medical-surgical oncologic intensive care unit (ICU).
Patients and Participants: Eighteen patients with SIRS/sepsis and multiple organ failure (MOF) and positive for aPL antibodies, included over a 10-month period.
aPL antibodies and coagulation parameters were measured up to 48 hours after the occurrence of acrocyanosis or arterial/venous thrombotic events. When current criteria for the diagnosis of aPL syndrome were applied, 16 patients met the criteria for “probable” and two patients had a definite diagnosis of APL syndrome in its catastrophic form (CAPS). Acrocyanosis, arterial events and venous thrombosis were present in eighteen, nine and five patients, respectively. Sepsis, cancer and major surgery were the main precipitating factors. All patients developed MOF during the ICU stay, with a hospital mortality rate of 72% (13/18). Five patients were discharged from the hospital. There were three survivors at 90 days of follow-up. New measurements of lupus anticoagulant (LAC) antibodies were performed in these three survivors and one patient still tested positive for these antibodies.
In this small series of patients, we observed a high frequency of auto-antibodies and micro- and macro-vascular thrombotic events in critically ill cancer patients. The coexistence of sepsis or SIRS and aPL antibodies was often associated with MOF and death. More studies are necessary to determine the pathophysiological significance of antiphospholipid antibodies in severely ill cancer patients.
PMCID: PMC2666481  PMID: 19219311
Antiphospholipid syndrome; Multiple organ failure; Cancer; Thrombosis; Sepsis; Lupus anticoagulant
16.  Long-Term Survival in a Large Cohort of Patients with Venous Thrombosis: Incidence and Predictors 
PLoS Medicine  2012;9(1):e1001155.
Linda Flinterman and colleagues report on the long-term mortality rate for individuals who have experienced a first venous thrombosis or pulmonary embolism. They describe an ongoing elevated risk of death for individuals who had experienced a venous thrombosis or pulmonary embolism as compared to controls, for up to eight years after the event.
Venous thrombosis is a common disease with a high mortality rate shortly after the event. However, details on long-term mortality in these patients are lacking. The aim of this study was to determine long-term mortality in a large cohort of patients with venous thrombosis.
Methods and Findings
4,947 patients from the Multiple Environmental and Genetic Assessment study of risk factors for venous thrombosis (MEGA study) with a first nonfatal venous thrombosis or pulmonary embolism and 6,154 control individuals without venous thrombosis, aged 18 to 70 years, were followed up for 8 years. Death and causes of death were retrieved from the Dutch death registration. Standardized mortality ratios (SMRs) were calculated for patients compared with control individuals. Several subgroups were studied as well.
736 participants (601 patients and 135 controls) died over a follow-up of 54,948 person-years. The overall mortality rate was 22.7 per 1,000 person-years (95% CI 21.0–24.6) for patients and 4.7 per 1,000 person-years (95% CI 4.0–5.6) for controls. Patients with venous thrombosis had a 4.0-fold (95% CI 3.7–4.3) increased risk of death compared with controls. The risk remained increased up to 8 years after the thrombotic event, even when no additional comorbidities were present. The highest risk of death was found for patients with additional malignancies (SMR 5.5, 95% CI 5.0–6.1). Main causes of death were diseases of the circulatory system, venous thrombosis, and malignancies. Main limitation was a maximum age of 70 at time of inclusion for the first event. Therefore results can not be generalized to those in the highest age categories.
Patients who experienced a first venous thrombosis had an increased risk of death which lasted up to 8 years after the event, even when no comorbidities were present at time of thrombosis. Future long-term clinical follow-up could be beneficial in these patients.
Please see later in the article for the Editors' Summary
Editors' Summary
The term venous thrombosis describes the clinical situation—more common during pregnancy, after surgery, or serious illness—in which a blood clot lodges in a vein. One specific type, which is more serious, involves the clot forming in a major vein in the lower leg and thigh and is termed a deep venous thrombosis. The clot can block blood flow and cause swelling and pain, but more seriously, can break off and move through the bloodstream, causing an embolism. An embolism can get stuck in the brain (and cause a stroke), lungs (and cause a pulmonary embolism), heart (to cause a heart attack), and/or other areas of the body, leading to severe damage.
Venous thrombosis is known to be associated with considerable short-term morbidity and mortality: the mortality rate after venous thrombosis is about 20% within one year and studies to date have suggested that the mortality rate is two to four times higher for patients with pulmonary embolism, of whom 10%–20% die within three months after the event. Many factors are associated with venous thrombosis, and the underlying cause of the thrombosis affects survival; for example, those with thrombotic events provoked by surgery or trauma have a lower mortality risk than patients with thrombosis caused by malignancy. Furthermore, about 10%–20% of patients who have had a venous thrombosis develop a recurrence within five years and up to 50% develop post-thrombotic syndrome—long-term swelling, pain, and changes in skin color.
Why Was This Study Done?
It is currently unknown whether the poor prognosis associated with venous thrombosis is limited to the months following the thrombotic event, or persists for years afterwards. So in this study, the researchers sought to answer this question by analyzing the long-term survival in a large cohort of patients who had experienced a first venous thrombosis and who were all followed for up to eight years.
What Did the Researchers Do and Find?
The researchers used the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis study (MEGA study), which was a case-control study involving 4,965 consecutive patients aged 18 to 70 years who were objectively diagnosed with a deep venous thrombosis or pulmonary embolism and recruited from six anticoagulation clinics in the Netherlands between March 1999 and September 2004. The control group consisted of partners of patients (n = 3,297) and a random control group matched on age and sex (n = 3,000). The researchers obtained causes of death from the Central Bureau of Statistics and for the observation period (30 days after the venous thrombosis, to either death or end of follow-up between February 2007 and May 2009) compared cause-specific death rates of the patients to those of the general Dutch population. The researchers devised specialist survival models (called Kaplan-Meier life-tables) and calculated standardized mortality ratios (SMRs—the ratio of the observed number of deaths over the number of deaths expected) to estimate relative rates of all cause mortality by type of the initial thrombosis and the underlying cause.
Using these methods, the researchers found that the overall mortality rate in patients with thrombosis was substantially greater than in the control group (22.7 per 1,000 person-years compared to 4.7 per 1,000 person-years). Apart from malignancies, the researchers found that the main causes of death were diseases of the circulatory and respiratory system. Patients with venous thrombosis and malignancy had the highest risk of mortality: 55% died during follow-up. Patients with venous thrombosis without malignancy had an overall 2-fold increased risk of mortality compared to the control group and this risk was comparable for patients with different forms of thrombosis (such as deep venous thrombosis and pulmonary embolus). According to the researchers' calculations, the relative risk of death was highest during the first three years after thrombosis, but for those with thrombosis of unknown cause, the risk of death increased by two-fold up to eight years after the thrombosis. Furthermore, the researchers found that the highly increased risk of death for those with pulmonary embolism is mainly only for the first month as long-term survival is similar to that of patients with a deep venous thrombosis.
What Do These Findings Mean?
These findings show that patients who have experienced a venous thrombosis for the first time have an increased risk of death, which may last up to eight years after the event. These findings have important clinical implications and suggest that long-term clinical follow-up could be beneficial in patients who have experienced a venous thrombosis for the first time.
Additional Information
Please access these Web sites via the online version of this summary at
Wikipedia provides information about venous thrombosis note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
Medline has patient-friendly information about deep venous thrombosis and pulmonary embolism
PMCID: PMC3254666  PMID: 22253578
17.  Clinical Implications of Elevated Antiphospholipid Antibodies in Adult Patients with Primary Immune Thrombocytopenia 
Antiphospholipid antibodies (aPL) have been detected in various proportions of patients with primary immune thrombocytopenia (ITP), but the clinical significance of this is debatable. The present study aimed to determine the frequency and clinical implications of elevated aPL in adult patients with ITP.
We prospectively studied newly diagnosed adult patients with ITP who were enrolled between January 2003 and December 2008 at Chungnam National University Hospital. They were evaluated for the presence of lupus anticoagulant (LA) and anticardiolipin antibodies (aCL) at diagnosis and were followed for the development of thrombosis.
Seventy consecutive patients with ITP (median age, 48 years; range, 18 to 79) were enrolled. Twenty patients (28.5%) were positive for aPL at the time of diagnosis: aCL alone in 15 (75%), aCL and LA in two (10%), and LA alone in three (15%). Patients who had platelet counts < 50,000/µL were administered oral prednisolone with or without intravenous immune globulin. No difference was found between the aPL-positive and -negative groups regarding gender, initial platelet count, and response to the therapy. After a median follow-up of 20 months (range, 2 to 68), two of 20 patients who were aPL-positive (10%) developed thrombosis, whereas no thrombotic event was found among those who were aPL-negative.
Our data suggest that aPL levels should be determined at the initial presentation of ITP and that patients found to be aPL-positive should receive closer follow-up for thrombotic events.
PMCID: PMC3245394  PMID: 22205846
Antibodies, anticardiolipin; Antiphospholipid syndrome; Purpura, thrombocytopenic, idiopathic; Lupus coagulation inhibitor; Thrombosis
18.  Factor V Leiden and Thrombosis in Patients with Systemic Lupus Erythematosus (SLE): A Meta-analysis 
Genes and immunity  2009;10(5):495-502.
To perform a meta-analysis of the association between the factor V Leiden polymorphism (FVL) and thrombosis among patients with SLE and/or antiphospholipid antibody (aPL) positivity. Included studies recruited patients based on SLE or aPL positive status, confirmed subjects' SLE diagnosis as defined by the American College of Rheumatology, and documented thrombotic events. Excluded studies were non-English or considered only arterial thrombosis. Individual patient data, available from five studies, together with unpublished data from 1210 European-American SLE patients from the UCSF Lupus Genetics Collection genotyped for FVL, were further analyzed. Seventeen studies (n=2090 subjects) were included in the initial meta-analysis. Unadjusted odds ratios (OR) were calculated to assess association of FVL with thrombosis. The OR for association of thrombosis with FVL was 2.88 (95% C.I. 1.98-4.20). In the secondary analysis with our individual patient dataset (n=1447 European-derived individuals), SLE subjects with the FVL polymorphism still had more than two times the odds of thrombosis compared to subjects without this polymorphism, even when adjusting for covariates such as gender, age, and aPL status. SLE and/or aPL positive patients with the FVL variant have more than two times the odds of thrombosis compared to those without this polymorphism.
PMCID: PMC2766554  PMID: 19421222
Systemic lupus erythematosus; factor V Leiden polymorphism; thrombosis; risk factors; antiphospholipid antibodies
19.  Assessment of the 2006 revised antiphospholipid syndrome classification criteria 
Annals of the Rheumatic Diseases  2007;66(7):927-930.
To analyse antiphospholipid (aPL) antibody‐positive patients using the 2006 revised antiphospholipid syndrome (APS) classification criteria.
A descriptive study of 200 aPL‐positive patients identified in a local, hospital‐based registry, analysing demographic, clinical and aPL characteristics. Patients were analysed for (1) fulfilment of the 1999 original (Sapporo) and 2006 revised APS classification criteria; (2) non‐criteria aPL features (for all aPL‐positive patients, based on the 2006 revised criteria definitions); and (3) non‐aPL thrombosis risk factors at the time of the clinical events (for patients with APS, based on the 2006 revised criteria stratifications).
Of the 200 patients, 183 patients had sufficient data for analysis. Of these, 39 (21%) patients did not meet the laboratory requirement of the original 1999 criteria. Of 81 patients with APS who met the 1999 classification criteria, 47 (58%) also met the 2006 revised criteria. Of 63 asymptomatic (no vascular or pregnancy events) aPL‐positive patients who met the laboratory requirement of the 1999 classification criteria, 38 (60%) also met the laboratory requirement of the 2006 revised criteria. More than 50% of the patients with APS with vascular events had identifiable non‐aPL thrombosis risk factors at the time of clinical events.
Only 59% of the patients meeting the 1999 APS Sapporo classification criteria met the 2006 APS classification criteria. The revised criteria will have positive implications in APS research by way of limiting the inclusion of a heterogeneous group of patients and also by way of providing a risk‐stratified approach.
PMCID: PMC2497429  PMID: 17337473
20.  A Case Series of HIV-Seropositive Patients and Hypercoagulable State—Is It Difficult to Treat Even with Therapeutic Anticoagulation? 
Patients with human immunodeficiency virus (HIV) are at risk of developing thrombosis and are 8 to 10 times more likely to develop thrombosis than the general population. Moreover, if they have hypercoagulable state they can have severe thrombosis and life-threatening thrombotic events. The purpose of this retrospective study is to analyze hypercoagulable state in HIV-seropositive patients who have been diagnosed with venous thromboembolism (VTE). This study is a subgroup study of a larger cohort group of HIV-seropositive patients with VTE followed up with our vascular medicine outpatient clinic. The patients included for this study were HIV-seropositive patients with hypercoagulable state, analyzed over the past 3 years, and followed prospectively. HIV-seropositive patients with arterial thrombosis were excluded. These patients had minimum, regular follow-up of 3 months, with a Doppler scan in the beginning and last follow-up. All the patients were analyzed for hypercoagulable state and the patients selected in this study were those who were tested positive for hypercoagulable state. All patients were analyzed for age, gender, race, site of thrombosis, coagulation factors, lipid panel, type of antiretroviral treatment, past or present history of infections or malignancy, CD4 absolute and helper cell counts at the beginning of thrombosis, and response to treatment and outcome. Patients with HIV with arterial thrombosis were excluded. The study was approved by the ethics committee. Five patients were included in this study. The mean age was 47.8 years (range 38 to 58 years). All were male patients with lower limb thrombosis. Most common venous thrombosis was popliteal vein thrombosis, followed by common femoral, superficial femoral, and external iliac thrombosis. Two patients had deficiency of protein S, two had high homocysteine levels, one had deficiency of antithrombin 3, and one had increase in anticardiolipin immunoglobulin G antibody. All the patients were taking nucleoside and nonnucleoside inhibitors but only one patient was taking protease inhibitors. There was no history of malignancy but two patients had past history of tuberculosis. The mean absolute CD4 counts were 244 cells/UL (range 103 to 392 cells/UL) and helper CD4 counts were 19.6 cells/UL (range 15 to 30 cells/UL). All were anticoagulated with warfarin or enoxaparin. There was complete resolution of deep vein thrombosis only in one patient on long-term anticoagulation but there was no resolution of thrombosis in the other four patients despite of therapeutic anticoagulation for more than 6 months. All the patients are alive and on regular follow-up. Thrombosis in HIV patients is seen more commonly in middle aged, community ambulant male patients. The most common hypercoagulable state was noted as deficiency of protein S and hyperhomocysteinemia. Eighty percent of the patients did not respond to therapeutic anticoagulation.
PMCID: PMC3709978  PMID: 24436593
deep vein thrombosis; duplex; DVT; enoxaparin; factor V Leiden; low molecular weight heparin; proximal
21.  Synergistic Effects of Hypofibrinolysis and Genetic and Acquired Risk Factors on the Risk of a First Venous Thrombosis 
PLoS Medicine  2008;5(5):e97.
Previously, we demonstrated that hypofibrinolysis, a decreased capacity to dissolve a blood clot as measured with an overall clot lysis assay, increases the risk of venous thrombosis. Here, we investigated the combined effect of hypofibrinolysis with established risk factors associated with hypercoagulability.
Methods and Findings
Fibrinolytic potential was determined with a plasma-based clot lysis assay in 2,090 patients with venous thrombosis and 2,564 control participants between 18 and 70 y of age enrolled in the Multiple Environmental and Genetic Assessment (MEGA) of risk factors for venous thrombosis study, a population-based case-control study on venous thrombosis. Participants completed a standardized questionnaire on acquired risk factors.
Hypofibrinolysis alone, i.e., clot lysis time (CLT) in the fourth quartile (longest CLT) (in absence of the other risk factor of interest) increased thrombosis risk about 2-fold relative to individuals with CLT in the first quartile (shortest CLT). Oral contraceptive use in women with CLT in the first quartile gave an odds ratio (OR) of 2.6 (95% confidence interval [CI] 1.6 to 4.0), while women with hypofibrinolysis who used oral contraceptives had an over 20-fold increased risk of venous thrombosis (OR 21.8, 95% CI 10.2 to 46.7). For immobilization alone the OR was 4.3 (95% CI 3.2 to 5.8) and immobilization with hypofibrinolysis increased the risk 10.3-fold (95% CI 7.7 to 13.8). Factor V Leiden alone increased the risk 3.5-fold (95% CI 2.3 to 5.5), and hypofibrinolysis in factor V Leiden carriers gave an OR of 8.1 (95% CI 5.3 to 12.3). The combination of hypofibrinolysis and the prothrombin 20210A mutation did not synergistically increase the risk. All ORs and 95% CIs presented are relative to individuals with CLT in the first quartile and without the other risk factor of interest.
The combination of hypofibrinolysis with oral contraceptive use, immobilization, or factor V Leiden results in a risk of venous thrombosis that exceeds the sum of the individual risks.
Frits Rosendaal and colleagues show that the combination of hypofibrinolysis with oral contraceptive use, immobilization, or factor V Leiden results in a risk of venous thrombosis that exceeds the sum of the individual risks.
Editors' Summary
When a blood vessel is injured, proteins in the blood called clotting factors “coagulate” (solidify) the blood at the injury site. The resultant clot (thrombus) plugs the wound and prevents blood loss. When the injury has healed, other proteins dissolve the clot, a process called “fibrinolysis.” Sometimes, however, a thrombus develops inside an undamaged blood vessel and partly or completely blocks the blood flow. A clot that occurs in one of the veins (vessels that take the blood to the heart) deep within the body (usually in the leg) is a deep vein thrombosis (DVT). Some DVTs have no symptoms; others cause pain, swelling, and tenderness in one leg. They are usually treated with heparin and warfarin, anticoagulant drugs that stop the clot growing. If left untreated, part of the clot (an embolus) can break off and travel to the lungs, where it can cause a life-threatening condition called a pulmonary embolism (PE).
Why Was This Study Done?
Most people are very unlikely to develop venous thrombosis (the collective term for DVT and PE), but anything that makes blood “hypercoagulable” (prone to clotting) increases this risk. Genetic risk factors can be inherited changes in blood clotting proteins (for example, a mutation in a gene coding for one protein, factor V, which is involved in clotting, is known as factor V Leiden—Leiden, The Netherlands, was where it was first described). There are also acquired risk factors such as taking oral contraceptives or being immobilized (for example, during bed rest). These risk factors often act in such a way that the risk of developing venous thrombosis for a person with multiple risk factors is greater than the sum of the individual risks. Another recently identified but little studied risk factor for venous thrombosis is “hypofibrinolysis,” a decreased capacity to dissolve blood clots. In this study (part of the “MEGA” study on risk factors for venous thrombosis), the researchers investigate the combined effect of hypofibrinolysis and established risk factors associated with hypercoagulability on the risk of developing venous thrombosis.
What Did the Researchers Do and Find?
The researchers collected blood from more than 2,000 individuals after their first DVT or PE and from a similar number of persons without venous thrombosis (controls). For each blood sample, they measured the time it took to dissolve a clot generated from that blood in a test tube (the clot lysis time or CLT) and determined which participants had the factor V Leiden mutation or a genetic change in the clotting factor prothrombin that also increases blood coagulability. The study participants also completed a questionnaire about acquired risk factors for venous thrombosis. The researchers divided the participants into four equal-sized groups (quartiles) based on their CLT and used the quartile with the lowest CLT as the reference group for their statistical analyses; hypofibrinolysis was defined as a CLT in the highest quartile (the longest times). Participants with hypofibrinolysis alone were twice as likely to develop venous thrombosis as those with a CLT in the lowest quartile (the shortest times). Oral contraceptive use alone increased the risk of venous thrombosis 2.5-fold, whereas the combination of oral contraceptive use and hypofibrinolysis increased the risk 20-fold. The researchers also found synergistic effects on thrombosis risk for hypofibrinolysis combined with immobilization or with the factor V Leiden mutation but not with the prothrombin mutation.
What Do These Findings Mean?
These findings confirm that persons with hypofibrinolysis and hence longer CLTs have a greater risk of developing venous thrombosis than those with short CLTs. Because CLTs were measured after venous thrombosis had occurred, hypofibrinolysis could be an effect rather than a cause of this condition. However, this is unlikely because there was no association between how long after the venous thrombosis the blood sample was taken and the measured CLT. These findings also show that the combination of hypofibrinolysis with immobilization, the factor V Leiden mutation, and oral contraceptive use greatly increases the risk of venous thrombosis. This new information about the risk factors for venous thrombosis should help physicians to advise patients about reducing their chances of developing this life-threatening condition.
Additional Information.
Please access these Web sites via the online version of this summary at
The MedlinePlus encyclopedia has pages on blood clots, deep vein thrombosis, and pulmonary embolism (in English and Spanish)
The US National Heart Lung and Blood Institute provides information on deep vein thrombosis, including an animation about how DVT causes pulmonary embolisms
The UK National Health Service Direct health encyclopedia provides information for patients on deep vein thrombosis (in several languages)
More information about the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA) study is available on the Leiden University Medical Center Web site
Wikipedia has pages on coagulation and on fibrinolysis (note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
PMCID: PMC2365975  PMID: 18462012
22.  Antiphospholipid Antibodies Predict Progression of Abdominal Aortic Aneurysms 
PLoS ONE  2014;9(6):e99302.
Antiphospholipid antibodies (aPLs) frequently occur in autoimmune and cardiovascular diseases and correlate with a worse clinical outcome. In the present study, we evaluated the association between antiphospholipid antibodies (aPLs), markers of inflammation, disease progression and the presence of an intra-aneurysmal thrombus in abdominal aortic aneurysm (AAA) patients.
APLs ELISAs were performed in frozen serum samples of 96 consecutive AAA patients and 48 healthy controls yielding positive test results in 13 patients (13.5%) and 3 controls (6.3%; n.s.). Nine of the 13 aPL-positive AAA patients underwent a second antibody testing >12 weeks apart revealing a positive result in 6 cases. APL-positive patients had increased levels of inflammatory markers compared to aPL-negative patients. Disease progression was defined as an increase of the AAA diameter >0.5 cm/year measured by sonography. Follow-up was performed in 69 patients identifying 41 (59.4%) patients with progressive disease. Performing multipredictor logistic regression analysis adjusting for classical AAA risk factors as confounders, the presence of aPLs at baseline revealed an odds ratio of 9.4 (95% CI 1.0–86.8, p = 0.049) to predict AAA progression. Fifty-five patients underwent a computed tomography in addition to ultrasound assessment indicating intra-aneurysmal thrombus formation in 82.3%. Median thrombus volume was 46.7 cm3 (1.9–377.5). AAA diameter correlated with the size of the intra-aneurysmal thrombus (corrcoeff = 0.721, p<0.001), however neither the presence nor the size of the intra-aneurysmal thrombus were related to the presence of aPLs.
In conclusion, the presence of aPLs is associated with elevated levels of inflammatory markers and is an independent predictor of progressive disease in AAA patients.
PMCID: PMC4076179  PMID: 24979700
23.  The dual role of innate immunity in the antiphospholipid syndrome 
Lupus  2010;19(4):347-353.
The antiphospholipid syndrome (APS), as both a primary syndrome and a syndrome in association with systemic lupus erythematosus (SLE), can be a devastating disease. It is unclear what factors (genetic and/or environmental) lead to the generation of antiphospholipid antibodies (aPL). It is equally unclear why only certain individuals with aPL develop clinical events. We hypothesize that innate immune activation plays a critical role at two distinct stages of APS, namely, the initiation phase, in which aPL first appear, and the effector phase, in which aPL precipitate a thrombotic event. According to the model we propose, aPL alone are insufficient to cause thrombosis and a concomitant trigger of innate immunity, e.g. a toll-like receptor (TLR) ligand, must be present for thrombosis to occur. Here, we discuss our findings that mice immunized with β2-glycoprotein I (β2GPI) and lipopolysaccharide (LPS), a TLR ligand, produce high levels of aPL and other SLE-associated autoantibodies, and develop lupus-like glomerulonephritis. We also discuss our data showing that autoantibodies to heat shock protein 60 (HSP60), an ‘endogenous TLR ligand’, promote thrombus generation in a murine model of arterial injury. Thus, both pathogen-derived TLR ligands (e.g. LPS) and endogenous TLR ligands (e.g. HSP60) may contribute to the pathogenesis of APS. This putative dual role of innate immunity provides new insight into the generation of aPL as well as the enigma of why some individuals with aPL develop APS, while others do not.
PMCID: PMC3440308  PMID: 20353968 CAMSID: cams2352
antiphospholipid syndrome; β2-glycoprotein I; heat shock protein 60; innate immunity; lipopolysaccharide; toll-like receptor ligands
24.  Serum complement activation on heterologous platelets is associated with arterial thrombosis in patients with systemic lupus erythematosus and antiphospholipid antibodies 
Lupus  2009;18(6):530-538.
Complement plays a major role in inflammation and thrombosis associated with systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS). A cross-sectional retrospective analysis was performed to evaluate serum complement fixation on platelets and thrombotic incidence using banked sera and clinical data from patients with SLE (n = 91), SLE with antiphospholipid antibodies (aPL) or APS (n = 78) and primary aPL (n = 57) or APS (n = 96). In-situ complement fixation was measured as C1q and C4d deposition on heterologous platelets using an enzyme-linked immunosorbent assay approach. Platelet activation by patient serum in the fluid phase was assessed via serotonin release assay. Enhanced in-situ complement fixation was associated with the presence of IgG aPL and IgG anti-β2 glycoprotein 1 antibodies (P < 0.05) and increased platelet activation (P < 0.005). Moreover, enhanced complement fixation, especially C4d deposition on heterologous platelets, was positively associated with arterial thrombotic events in patients with SLE and aPL (P = 0.039). Sera from patients with aPL possess an enhanced capacity for in-situ complement fixation on platelets. This capacity may influence arterial thrombosis risk in patients with SLE.
PMCID: PMC2707931  PMID: 19395455
antiphospholipid syndrome; systemic lupus erythematosus; thrombosis
25.  The persistence of anticardiolipin antibodies is associated with an increased risk of the presence of lupus anticoagulant and anti-β2-glycoprotein I antibodies 
Rheumatology (Oxford, England)  2006;45(9):1116-1120.
We studied antiphospholipid antibodies (aPL) in blood samples from a cohort of individuals followed for thrombosis to determine whether the persistent presence of anticardiolipin antibodies (aCL) is associated with a greater likelihood of having lupus anticoagulant and/or anti-β2-glycoprotein I antibodies (LA/aβ2GPI).
Blood samples from 353 individuals who had been tested for aCL on at least two occasions were tested for aβ2GPI and LA. Two groups were defined: aCL-persistent, who tested aCL-positive on at least two occasions, and aCL non-persistent, who tested aCL-positive on fewer than two occasions. Multivariate logistic regressions were performed using LA/aβ2GPI, LA and aβ2GPI as outcome variables and the percentage of aCL-positive tests as the predictor variable, adjusted for age, gender, family history of cardiovascular disease (CVD), systemic lupus erythematosus (SLE), smoking and number of venous (VT) and arterial thromboses (AT).
Sixty-eight (19%) individuals were aCL persistent and 285 (81%) were aCL non-persistent. LA/aβ2GPI was found in 36 (53%) of the aCL persistent group and 38 (13%) of the aCL non-persistent group. The two groups were similar for age, gender and smoking. Family history of CVD, SLE, VT and AT were more frequent in the aCL persistent group. Multivariate analyses revealed that odds ratios for LA/aβ2GPI, LA and aβ2GPI were 1.34 [95% confidence interval (CI)=1.22–1.47], 1.36 (95% CI=1.24–1.50) and 1.47 (95% CI=1.31–1.65) respectively for each 10% increase in aCL-positive tests vs 0% positive tests.
Persistence of aCL positivity is associated with an increased risk of LA/aβ2GPI.
PMCID: PMC3435425  PMID: 16510527 CAMSID: cams2311
Antiphospholipid antibodies; Anticardiolipin antibodies; Lupus anticoagulant; Anti-β2-glycoprotein I antibodies

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