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Rheumatology Advance Access published online on October 17, 2008
Rheumatology, doi:10.1093/rheumatology/ken382
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© The Author 2008. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org

Primary antiphospholipid syndrome: a low-grade auto-inflammatory disease?

P. R. J. Ames1,2, I. Antinolfi3, A. Ciampa4, J. Batuca5, G. Scenna3, L. R. Lopez6, J. Delgado Alves5, L. Iannaccone3 and E. Matsuura7

1Immunoclot Ltd, Leeds, 2Royal Preston Hospital, Preston, UK, 3Coagulation Unit, Cardarelli Hospital, Naples, 4Coagulation Unit, Moscati Hospital, Avellino, Italy, 5Pharmacology Department, New University of Lisbon, Lisbon, Portugal, 6Corgenix Inc., Broomfield, CO, USA and 7Biochemistry Department, University of Okayama, Okayama, Japan.

Correspondence to: P. R. J. Ames, 3 Malden Road, Leeds LS6 4QT, UK. E-mail: paxmes{at}aol.com


   Abstract
Top
 Abstract
Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 
Objective. To test the inflammation and immune activation hypothesis in primary thrombotic APS (PAPS) and to identify clinical and laboratory factors related to inflammation and immune activation.

Methods. PAPS (n = 41) patients were compared with patients with inherited thrombophilia (IT, n = 44) and controls (CTR, n = 39). IgG aCL, IgG anti-β2-glycoprotein I (β2GPI), high-sensitivity CRP (hs-CRP), serum amyloid A (SAA), CRP bound to oxidized low-density lipoprotein–β2GPI complex (CRP–oxLDL–β2GPI) (as inflammatory markers) neopterin (NPT), soluble CD14 (sCD14) (as immune activation markers) were measured by ELISA.

Results. After correction for confounders, PAPS showed higher plasma levels of hs-CRP (P = 0.0004), SAA (P < 0.01), CRP–oxLDL–β2GPI (P = 0.0004), NPT (P < 0.0001) and sCD14 (P = 0.007) than IT and CTR. Two regression models were applied to the PAPS group: in the first, IgG aCL and IgG β2GPI were included amongst the independent variables and in the second they were excluded. In the first model, SAA (as the dependent variable) independently related to thrombosis number (P = 0.003); NPT (as the dependent variable) independently related to thrombosis type (arterial, P = 0.03) and number (P = 0.04); sCD14 (as the dependent variable) independently related to IgG β2GPI (P = 0.0001), age (0.001) and arterial thrombosis (P = 0.01); CRP–oxLDL–β2GPI (as the dependent variable) independently related to IgG β2GPI (P = 0.0001). In the second model, sCD14 and NPT independently related to each other (P = 0.002) (this was noted also in the IT group, P < 0.0001) and CRP–oxLDL–β2GPI independently predicted SAA (P = 0.002).

Conclusion. Low-grade inflammation and immune activation occur in thrombotic PAPS and relate to clinical features and aPL levels.

KEY WORDS: Anti-phospholipid syndrome, C-reactive protein, Serum amyloid A, Neopterin, Soluble CD14


   Introduction
Top
 Abstract
 Introduction
Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 
The primary APS (PAPS) is characterized by the occurrence of single- or multiple-vessel occlusion in the presence and persistence of aPLs tested by immune or by clotting assays in isolation or in combination over a minimum period of 3 months [1].

The presence of antibodies and T-cell clones against β2-glycoprotein I (β2GPI) in the peripheral blood of affected patients define PAPS as an autoimmune disorder [1–3]. Antibodies against β2GPI promote endothelial cell, monocyte and coagulation activation: the vessel wall shifts to a pro-adhesive and pro-thrombotic phenotype [4], monocytes express and release TNF and tissue factor [5] and thrombosis may ensue.

Circulating levels of pro-inflammatory cytokines are elevated in APS [6–8] and some novel pro-inflammatory genes are up-regulated in endothelial cells stimulated with IgG β2GPI [9], but PAPS is not an inflammatory disorder in the traditional sense as only modest increases of CRP have been detected [10–13]. Despite the presence of auto-reactive T-cell clones [2, 3] in vivo markers of immune activation have not been investigated in PAPS. Stimulated T helper cells release IFN-{gamma} [14] that activates monocytes with the release of neopterin (NPT) and modulation of their surface component CD14 [15]. Therefore, NPT is a specific marker of immune cooperation, whereas soluble CD14 (sCD14) may also reflect monocyte activation in the absence of IFN-{gamma} as it can behave as an acute-phase reactant [16].

Moreover, the observation that β2GPI is a ligand for oxidized low-density lipoprotein (oxLDL) [17] and that the resulting oxLDL–β2GPI complex binds CRP [18] prompted us to evaluate the clinical relevance of CRP, serum amyloid A (SAA) (inflammatory markers), NPT and sCD14 (immune activation markers) and their relationship with oxLDL–β2GPI–CRP in thrombotic patients with PAPS.


   Materials and methods
Top
 Abstract
 Introduction
 Materials and methods
Results
 Discussion
 Acknowledgements
 References
 
Patients and blood sampling
The study was conceived as a cross-sectional case double-control to serve as a baseline for an interventional trial. Consecutive thrombotic patients fulfilling recent criteria for PAPS [1] and patients with IT attending the Coagulation Unit of the Cardarelli Hospital (Naples, Italy) were invited to participate in the study that was carried out according to the revised Declaration of Helsinki, with approval of the Ethics Board of the Hospital and the written consent of all participants. Exclusion criteria were acute or chronic hepatic, renal, lung disease, diabetes, a recent history of acute infection (within 6 weeks), post-thrombotic syndrome with venous ulcerations, a positive urinary dipstick for nitrates on the day of sampling, treatment with steroids, statins and fibrates. Patients are seen on average every 3–4 weeks for their oral anti-coagulation monitoring and are instructed to self-report any illness they might incur during the intervening periods. Every year, their lipid profile, kidney and liver function tests are checked. Of the PAPS attendees (n = 50), two were excluded because they had gradually developed AS and SLE, one had developed kidney cancer, two were pregnant, one had suffered a recent recurrent event, one had post-thrombotic syndrome and two were evasive regarding their smoking and contraceptive status. Of the IT (n = 46) attendees, two were excluded for venous ulcerations in lower limbs. The study therefore included 41 thrombotic PAPS patients, 44 IT patients and 39 control subjects. The laboratory criteria for diagnosis of APS define Category IIa as lupus anti-coagulant (LA) alone, IIb as aCL alone, IIc as anti-β2GPI alone and Category I as any combination of the previous [1]: of our PAPS patients, eight were in laboratory Category IIa and the remaining in Category I. From the therapeutic viewpoint, all were taking warfarin, three were on carbamezapine for post-ischaemic epilepsy, two on β-blockers six on folic acid. Of the IT patients, all were on warfarin, two were on β-blockers five on folic acid and two on angiotensin-converting enzyme inhibitors. The control group included 19 blood donors, 9 healthy hospital personnel and 11 subjects on warfarin for mitral valve replacement (mitral valve prolapse, n = 4; childhood rheumatic fever, n = 4; ventricular septal defects with congenital mitral incompetence, n = 3) that occurred on average 22 ± 8 yrs earlier. This partially accounts for the lifelong warfarin intake of the other two groups. Demographics and clinical features of all participants are shown in Table 1. Blood samples were drawn between 8:00 and 10:00 a.m. by neat venepuncture into 5 ml citrate vacutainers, spun immediately at room temperature at 4000 r.p.m. x 6 min; supernatant plasma was spun again at room temperature at 12 000 r.p.m. x 4 min to obtain platelet-poor plasma: aliquots of the latter were frozen at –80°C and thawed on the day of the testing: markers were measured from different aliquots of the same sample.


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  		TABLE 1. Demographics of participants

 
aPLs
All PAPS patients had their LA screened by activated partial thromboplastin time (aPTT), dilute Russell's viper venom time (DRVVT) and kaolin clotting time (KCT) according to established guidelines [1]. A clotting time ratio between sample and control plasma >1.2 for aPTT, >1.18 for DRVVT and >1.3 for KCT indicated an abnormal result. After demonstrating the presence of an inhibitor by mixing studies, the platelet neutralization procedure confirmed the presence of a lupus inhibitor in aPTT and DRVVT and high phospholipid concentration in KCT. During follow-up, persistence of LA in aPTT was confirmed by comparing sensitive and insensitive reagents to LA [19]. IgG aCL (Cambridge Life Sciences, UK) and IgG anti-β2GPI (Corgenix, Westminster, CO, USA) were measured according to the manufacturer instructions by ELISA. IgG aCL was measured yearly since inception of the PAPS cohort (1994) whereas IgG anti-β2GPI has been measured yearly since 2004.

ELISA for oxLDL–β2GPI complexes
Capture anti-β2GPI mAb, WB-CAL-1, was adsorbed on a microtitre plate (Immulon 2HB, Dynex Technologies, Inc., Chantily, VA, USA) by incubating at 8 µg/ml (dissolved in Hepes buffer, 50 µl/well) at 4°C overnight. The plate was blocked with 1% skim milk for 1 h. Serum samples (100-fold diluted) were added to the wells (100 µl/well) and incubated for 2 h. The wells were subsequently incubated with biotinyl-anti-apoB-100 antibody (1D2) for 1 h and HRP-labelled avidin for 30 min. Colour was developed with o-phenylenediamine and H2O2. The reaction was terminated by 2N sulphuric acid, and the OD at 490 nm was measured. Between each step, extensive washing was performed using Hepes buffer containing 0.05% Tween-20. The mean OD of blank wells corrected the raw OD of samples in individual assays. When 1.0 U/ml was adjusted to 3 S.D. above the mean of serum samples from 50 normal subjects, 1.0 U/ml of the oxLDL12 h–β2GPI16 h complex was equilibrated to ~4.5 µg/ml of apoB equivalent. A sample was considered positive when its reactivity was >1.0 U/ml.

ELISA for CRP–oxLDL–β2GPI complexes
Capture anti-βGPI mAb, WB-CAL-1, was adsorbed onto microtitre plates (Immulon 2HB; Thermo Labsystems) by incubating at 8 µg/ml (dissolved in Hepes buffer, 50 µl/well) at 4°C overnight. After blocking with 10 mM Tris, 150 mM NaCl, 1.25 mM CaCl2, pH7.4, (Tris buffer) containing 0.5% BSA, samples diluted 1 : 100 with Tris buffer containing 0.2% BSA were added to each well and incubated for 2 h. The wells were subsequently incubated with HRP-labelled anti-CRP antibodies for 1 h. Extensive washing between steps was performed with Tris buffer containing 0.05% Tween-20. Further steps were performed as described above for oxLDL–β2GPI complexes.

Measurement of inflammatory and immune parameters
The hs-CRP, NPT (Biosupply Ltd, Bradford, UK), SAA (Europa Bioproducts, Ely, UK) and sCD14 (R&D Systems, Abingdon, UK) were measured by ELISA according to the manufacturer's instructions. The cut-off for the upper normal level of all variables in the study was set at the mean + 5 S.E.M of the control group. Throughout the manuscript, CRP stands for the high-sensitivity measurement.

Statistical analyses
Data are shown as mean ± S.D. Analysis of variance (ANOVA), analysis of covariance (ANCOVA) and Student's t-test assessed differences between groups where appropriate, multiple regression models assessed associations between variables and chi-square analysis assessed differences between proportions. Sensitivity was calculated as true positives divided by the sum of true positives and false negatives multiplied by 100. Specificity was calculated as true negatives divided by the sum of true negatives and false positives multiplied by 100. All statistical analyses were done using SPSS (Chicago, Illinois, USA).


   Results
Top
 Abstract
 Introduction
 Materials and methods
 Results
Discussion
 Acknowledgements
 References
 
Comparison of inflammatory and immune markers across groups
Average plasma levels of CRP, SAA, NPT, sCD14, CRP–oxLDL–β2GPI and oxLDL–β2GPI were higher in PAPS than other groups considered (Fig. 1). Amongst age, gender, menopause, oral contraception, smoking and obesity, ANCOVA identified only age as a significant confounder for NPT (P = 0.007), sCD14 (P = 0.0001), oxLDL–β2GPI (P = 0.02) and SAA (P = 0.04). Age-adjusted significances between groups were P < 0.01 for SAA, P < 0.0001 for NPT, P = 0.007 for sCD14, P = 0.0001 for oxLDL–β2GPI. Within PAPS, IT and CTR, the proportion of participants positive for CRP was 31, 13 and 10%, respectively (P = 0.02), for SAA 31, 6 and 2%, respectively (P < 0.0001), for NPT 68, 27 and 15%, respectively (P < 0.0001), for sCD14 48, 34 and 23%, respectively (0.054), for CRP–oxLDL–β2GPI 53, 31 and 18%, respectively (P < 0.003), oxLDL–β2GPI 41, 9 and 10%, respectively (P = 0.0002). Sensitivity and specificity of CRP–oxLDL–β2GPI was 51 and 100%, respectively with regards to thrombotic PAPS, but 53 and 64%, respectively with regards to arterial thrombosis.


Figure 1
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  		FIG. 1. Average levels of (A) hs-CRP, (B) SAA, (C) NPT, (D) sCD14, (E) CRP bound to the oxLDL–β2GPI and (F) oxLDL–β2GPI complex in PAPS, IT and CTR. The long horizontal bar is the cut-off level for each variable arbitrarily set at the mean +5 S.E.M. The P-value represents the overall ANOVA significance. Bonferroni's multiple comparison revealed: for hs-CRP, PAPS vs IT and PAPS vs CTR, both P ≤ 0.01; for SAA, PAPS vs CTR, P < 0.01; for NPT, PAPS vs IT and PAPS vs CTR, both P < 0.001; for CRP–oxLDL–β2GPI, PAPS vs IT and PAPS vs CTR, both P < 0.01; for oxLDL–β2GPI PAPS vs IT and PAPS vs CTR, both P < 0.01. No post hoc values were derived for sCD14.

 
Relationship amongst variables in the PAPS group
Two regression models were employed: the first assessed the predictive effect of IgG aCL, IgG β2GPI, gender, event type, event number, age at event and smoking status on plasma levels of CRP, SAA, NPT, sCD14, CRP–oxLDL–β2GPI and oxLDL–β2GPI; the second assessed the relationship between immune activation markers and inflammatory markers after correction for gender, event type, event number, age at event, smoking status in the absence of IgG aCL and IgG β2GPI.

Remarkably, in the first model, IgG β2GPI was an independent predictor of SAA, NPT, sCD14 and CRP–oxLDL–β2GPI. The number of thrombotic events predicted SAA and NPT, whereas arterial thrombosis predicted NPT and sCD14 (Table 2). Indeed, the average plasma concentration of NPT was greater in patients with arterial than venous thrombosis (16.7 ± 2.4 vs 11 ± 0.9 nmol/ml, P = 0.02) but that of sCD14 did not reach significance (data not shown). On the other hand, average plasma concentration of SAA was almost 50% higher in patients with arterial than venous thrombosis (85 ± 18 vs 45 ± 9 mg/ml, P = 0.04). In the second regression model, NPT and sCD14 correlated with each other as did CRP–oxLDL–β2GPI and SAA (Table 3).


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  		TABLE 2. Independent predictors of inflammatory and immune activation markers in PAPS including IgG aCL and IgG β2GPI as independent variables

 

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  		TABLE 3. Independent predictors of inflammatory and immune activation markers in PAPS excluding IgG aCL and IgG β2GPI from the regression model

 
Relationship amongst variables in the IT group
Multiple regression analysis strongly revealed interrelations between SAA and CRP as well as between NPT and sCD14 (Table 4).


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  		TABLE 4. Independent predictors of inflammatory and immune activation markers in inherited thrombophilia

 
Relationship amongst variables in the control group
Multiple regression analysis identified oxLDL–β2GPI as an independent predictor of CRP, SAA and sCD14, whereas the inflammatory markers were strongly related (Table 5).


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  		TABLE 5. Independent predictors of inflammatory and immune activation markers in normal controls

 

   Discussion
Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
Acknowledgements
 References
 
CRP and SAA are acute-phase plasma proteins principally expressed and induced in the liver under the regulation of the pro-inflammatory cytokines IL-1, IL-6 and TNF-{alpha} though non-acute-phase elevations may occur in several chronic inflammatory diseases such as RA and atherosclerosis [20]. The current survey reveals that a significant number of thrombotic PAPS patients display a low-grade inflammatory state that must be due to the disease itself, as IT patients did not show similar elevations of CRP and SAA. Thus, we support a relationship independent of thrombosis between LA and the inflammatory markers, CRP [12], factor VIII and fibrinogen [11], but failed to confirm our previous data on higher CRP in PAPS with arterial occlusions, probably due to the larger sample and different patients herein [10]. However, elevated levels of CRP independently predicted residual or recurrent symptoms in a cohort of aPL-positive patients with neurological manifestations, mostly cerebral infarctions and transient ischaemic attacks [13].

Contrary to the lack of clinical relevance of SAA in a very small PAPS group [21], SAA was elevated in our patients particularly in relation to multiple thrombotic events. Unfortunately, the cross-sectional nature of the study cannot define whether elevated SAA and CRP are cause or effect of previous occlusive events since both molecules are involved in the expression of tissue factor on monocytes and endothelial cells [22, 23]. Therefore, their value as thrombotic risk markers in PAPS may only be assessed with regards to re-thrombosis as most PAPS patients will be on oral anti-coagulation after their first occlusive event.

Compared with IT and controls, our PAPS patients displayed higher plasma concentrations of NPT and of sCD14 that correlated strongly in both patient groups. In PAPS, NPT was higher in patients with multiple thromboses and both markers related to arterial occlusions: monocytes are more likely to be involved in the pathogenesis of arterial than venous thrombosis [24]. The independent predictive power of IgG β2GPI vs sCD14 and NPT reflects the in vitro work describing monocyte activation including tissue factor expression by IgG β2GPI [5, 25] that adds to the T-helper activation pathway.

In a similar context, monocytes may differentiate into foam cells after the uptake of an immune complex consisting of β2GPI, oxLDL and a monoclonal aPL [25]. Though oxLDL–β2GPI complex is formed as an attempt by β2GPI to prevent LDL oxidation and its uptake by monocyte scavenger receptors, it is recognized by specific antibodies and up-taken by monocytes via Fc receptors [26]. Monocytes play a pivotal role in APS: the direct effect of IgG β2GPI promotes tissue factor expression [5, 25] and hence clotting in the bloodstream, whereas phagocytosis of oxLDL–β2GPI bound to their specific antibody probably favours atherosclerosis [27].

OxLDL–β2GPI complexes are found in primary and secondary APS, SLE [27] and chronic nephritis [28], disorders characterized by enhanced oxidative stress [29, 30]. In PAPS, we and others had noted a correlation between plasma IgG aCL and isoprostanes, sensitive markers of in vivo oxidative stress [31, 32], and in the light of the above this could explain the relationship between IgG aCL and oxLDL–β2GPI in the present PAPS population.

Experimental work reveals that in analogy with certain natural antibodies and scavenger receptors, CRP binds phosphorylcholine (PC) moieties on apoptotic cells and on oxLDL in what appears a very primitive form of innate immunity [17]. More recent in vitro data demonstrate that over a 24-h incubation period CRP can bind oxLDL–β2GPI via PC in a ternary complex [8]. Given the very short half-life (10 min) oxLDL when injected into mice and the co-localization of CRP, oxLDL and β2GPI with foamy macrophages in carotid artery plaques CRP–oxLDL–β2GPI would fulfil the requirements for a specific marker of atherosclerosis [8], a hot topic in APS.

In this study CRP–oxLDL–β2GPI was 100% specific for PAPS but did not differentiate arterial and venous thrombosis. Interestingly, higher CRP–oxLDL–β2GPI was predicted by elevated IgG β2GPI, indicating that an enhanced level of LDL oxidation requires buffering from both β2GPI and CRP. LDL oxidation is prevented by paraoxonase (PON), the enzyme that accounts for most of the anti-oxidant activity of HDL: in PAPS, decreased PON activity associates with elevated IgG β2GPI titres and a monoclonal aPL inhibited PON activity (PONa) in vitro [33]. On the other hand, β2GPI buffering of oxLDL would lead to exposure of cryptic auto-antigenic epitopes on β2GPI with persisting antibody stimulation [34]. In the case of the oxLDL–βß2GPI complex, the antibody response would be mostly IgG aCL; once the CRP–oxLDL–β2GPI is formed, the highly specific IgG β2GPI would be stimulated.

In the control group, no patient had elevated CRP–oxLDL–β2GPI, but some had elevated oxLDL–β2GPI that was an independent predictor of CRP, SAA and sCD14: a possibility is that CRP–oxLDL–β2GPI and oxLDL–β2GPI are formed at high and low LDL oxidation levels, as would occur in PAPS and normal subjects, respectively. In the latter case, only β2GPI is required to buffer oxLDL though the resulting oxLDL–β2GPI complex still associates with CRP.

In conclusion, immune activation and low-grade inflammation occur in PAPS. The former was not unexpected but the latter raises further issues: are the inflammatory markers measured of liver or vascular origin? Endothelial cells, smooth muscle cells and monocytes can produce CRP as well as SAA in atherosclerotic lesions [35–37]. Indeed, CRP–oxLDL–β2GPI related to SAA in this survey. Outside the acute setting, mild plasma elevations of CRP, SAA and NPT represent an inflammatory signature of advanced atherosclerosis [38, 39] but do not add discriminatory diagnostic power over established cardiovascular risk factors [40]. The picture may be different in PAPS where atherosclerosis may not necessarily involve traditional cardiovascular risk factors [41]: as number and type of events were linked to plasma levels of CRP, SAA and NPT these may represent useful markers alongside CRP–oxLDL–β2GPI to predict vascular disease progression and to monitor monocyte and vascular activity in interventional trials [42–44].

Formula


   Acknowledgements
Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
References
 
We are grateful to Brunella Capano for her continuing nursing and organizational support throughout a difficult period of equipment transfer.

Funding: The financial support of Senit Foundation, Scotland, UK is greatly appreciated.

Disclosure statement: L.R.L. is employed by Corgenix Inc., Broomfield, CO, USA. All other authors have declared no conflicts of interest.


   References
Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 

  1. Miyakis S, Lockshin MD, Atsumi T, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost (2006) 4:295–306.[CrossRef][Web of Science][Medline]
  2. Hattori N, Kuwana M, Kaburaki J, Mimori T, Ikeda Y, Kawakami Y. T cells that are autoreactive to beta2-glycoprotein I in patients with antiphospholipid syndrome and healthy individuals. Arthritis Rheum (2000) 43:65–75.[CrossRef][Web of Science][Medline]
  3. Arai T, Yoshida K, Kaburaki J, et al. Autoreactive CD4(+) T-cell clones to beta2-glycoprotein I in patients with antiphospholipid syndrome: preferential recognition of the major phospholipid-binding site. Blood (2001) 98:1889–96.[Abstract/Free Full Text]
  4. Meroni PL, Raschi E, Testoni C, et al. Statins prevent endothelial cell activation induced by antiphospholipid (anti-beta2-glycoprotein I) antibodies: effect on the proadhesive and proinflammatory phenotype. Arthritis Rheum (2001) 44:2870–78.[CrossRef][Web of Science][Medline]
  5. Sorice M, Longo A, Capozzi A, et al. Anti-beta2-glycoprotein I antibodies induce monocyte release of tumour necrosis factor alpha and tissue factor by signal transduction pathways involving lipid rafts. Arthritis Rheum (2007) 56:2687–97.[CrossRef][Web of Science][Medline]
  6. Ahmed K, Vianna JL, Khamashta MA, Hughes GRV. IL-2, IL-6 and TNF levels in primary antiphospholipid syndrome. Clin Exp Rheumatol (1992) 10:503.[Web of Science][Medline]
  7. Bertolaccini ML, Atsumi T, Lanchbury JS, et al. Plasma tumor necrosis factor alpha levels and the -238*A promoter polymorphism in patients with antiphospholipid syndrome. Thromb Haemost (2001) 85:198–203.[Web of Science][Medline]
  8. Forastiero RR, Martinuzzo ME, de Larrañaga GF. Circulating levels of tissue factor and proinflammatory cytokines in patients with primary antiphospholipid syndrome or leprosy related antiphospholipid antibodies. Lupus (2005) 14:129–36.[Abstract/Free Full Text]
  9. Hamid C, Norgate K, D’Cruz DP, et al. Anti-beta2-GPI-antibody-induced endothelial cell gene expression profiling reveals induction of novel pro-inflammatory genes potentially involved in primary antiphospholipid syndrome. Ann Rheum Dis (2007) 66:1000–7.[Abstract/Free Full Text]
  10. Ames PRJ, Tommasino C, Brancaccio V, Ciampa A. C-reactive protein in primary antiphospholipid syndrome. J Rheumatol (2007) 34:650.[Free Full Text]
  11. Sailer T, Vormittag R, Pabinger I, et al. Inflammation in patients with lupus anticoagulant and implications for thrombosis. J Rheumatol (2005) 32:462–8.[Abstract/Free Full Text]
  12. Sidelmann JJ, Sjoland JA, Gram J, et al. Lupus anticoagulant is significantly associated with inflammatory reactions in patients with suspected deep vein thrombosis. Scand J Clin Lab Invest (2007) 67:270–9.[CrossRef][Web of Science][Medline]
  13. Miesbach W, Gokpinar B, Gilzinger A, Claus D, Scharrer I. Predictive role of hs-C-reactive protein in patients with antiphospholipid syndrome. Immunobiology (2005) 210:755–60.[CrossRef][Web of Science][Medline]
  14. Hoffmann G, Wirleitner B, Fuchs D. Potential role of immune system activation-associated production of neopterin derivatives in humans. Inflamm Res (2003) 52:313–21.[CrossRef][Web of Science][Medline]
  15. Bazil V, Strominger JL. Shedding as a mechanism of down-modulation of CD14 on stimulated human monocytes. J Immunol (1991) 147:1567–74.[Abstract]
  16. Bas S, Gauthier BR, Spenato U, Stingelin S, Gabay C. CD14 is an acute-phase protein. J Immunol (2004) 172:4470–9.[Abstract/Free Full Text]
  17. Chang M, Binder CJ, Torzewski M, Witztum JL. C-reactive protein binds to both oxidized LDL and apoptotic cells through recognition of a common ligand: phosphorylcholine of oxidized phospholipids. Proc Natl Acad Sci USA (2002) 99:13043–8.[Abstract/Free Full Text]
  18. Tabuchi M, Inoue K, Usui-Kataoka H, et al. The association of C-reactive protein with an oxidative metabolite of LDL and its implication in atherosclerosis. J Lipid Res (2007) 48:768–81.[Abstract/Free Full Text]
  19. Brancaccio V, Ames PRJ, Glynn J, Iannaccone L, Mackie IJ. A rapid screen for lupus anticoagulant (LA) by comparing a sensitive and insensitive aPTT reagent provides also good discrimination from oral anticoagulants, congenital factor deficiency and heparin. Blood Coagul Fibrin (1997) 8:155–60.[Web of Science][Medline]
  20. Zhang N, Ahsan MH, Purchio AF, West DB. Serum amyloid A-luciferase transgenic mice: response to sepsis, acute arthritis, and contact hypersensitivity and the effects of proteasome inhibition. J Immunol (2005) 174:8125–34.[Abstract/Free Full Text]
  21. Sodin-Semrl S, Zigon P, Cucnik S, et al. Serum amyloid A in autoimmune thrombosis. Autoimmun Rev (2006) 1:21–7.
  22. Cai H, Song C, Endoh I, et al. Serum amyloid A induces monocyte tissue factor. J Immunol (2007) 178:1852–60.[Abstract/Free Full Text]
  23. Cai H, Song C, Lim IG, Krilis SA, Geczy CL, McNeil HP. Importance of C-reactive protein in regulating monocyte tissue factor expression in patients with inflammatory rheumatic diseases. J Rheumatol (2005) 32:1224–31.[Abstract/Free Full Text]
  24. Burnand KG, Gaffney PJ, McGuinness CL, Humphries J, Quarmby JW, Smith A. The role of the monocyte in the generation and dissolution of arterial and venous thrombi. Cardiovasc Surg (1998) 6:119–25.[CrossRef][Web of Science][Medline]
  25. López-Pedrera C, Buendía P, Cuadrado MJ, et al. Antiphospholipid antibodies from patients with the antiphospholipid syndrome induce monocyte tissue factor expression through the simultaneous activation of NF-kappaB/Rel proteins via the p38 mitogen-activated protein kinase pathway, and of the MEK-1/ERK pathway. Arthritis Rheum (2006) 54:301–11.[CrossRef][Web of Science][Medline]
  26. Hasunuma Y, Matsuura E, Makita Z, Katahira T, Nishi S, Koike T. Involvement of β2-glycoprotein I and anticardiolipin antibodies in oxidatively modified low-density lipoprotein uptake by macrophages. Clin Exp Immunol (1997) 7:569–73.
  27. Kobayashi K, Kishi M, Atsumi T, et al. Circulating oxidized LDL forms complexes with beta2-glycoprotein I: implication as an atherogenic autoantigen. J Lipid Res (2003) 44:716–26.[Abstract/Free Full Text]
  28. Kasahara J, Kobayashi K, Maeshima Y, et al. Clinical significance of serum oxidized low-density lipoprotein/beta2-glycoprotein I complexes in patients with chronic renal diseases. Nephron Clin Pract (2004) 98:15–24.[CrossRef]
  29. Ames PRJ, Alves J, Inanc M, Isenberg DA, Nourooz-Zadeh J. Oxidative stress in systemic lupus erythematosus and allied disorders with vascular involvement. Rheumatology (1999) 38:529–34.[Abstract/Free Full Text]
  30. Cottone S, Lorito MC, Riccobene R, et al. Oxidative stress, inflammation and cardiovascular disease in chronic renal failure. J Nephrol (2008) 21:175–9.[Web of Science][Medline]
  31. Ames PRJ, Nourooz-Zadeh J, Tommasino C, Alves J, Brancaccio V, Anggard EE. ‘Oxidative stress’ in primary antiphospholipid syndrome. Thromb Haemost (1998) 79:447–9.[Web of Science][Medline]
  32. Iuliano L, Praticò D, Ferro D, et al. Enhanced lipid peroxidation in patients positive for antiphospholipid antibodies. Blood (1997) 90:3931–5.[Abstract/Free Full Text]
  33. Delgado Alves J, Ames PRJ, Donohue S, Norouz-Zadeh J, Isenberg DA. Antibodies towards high-density lipoprotein, Apo-A-I and cardiolipin inversely correlate to paraoxonase activity in systemic lupus erythematosus and primary antiphospholipid syndrome. Possible atherogenic mechanisms. Arthritis Rheum (2002) 46:2686–94.[CrossRef][Web of Science][Medline]
  34. Yamaguchi Y, Seta N, Kaburaki J, Kobayashi K, Matsuura E, Kuwana M. Excessive exposure to anionic surfaces maintains autoantibody response to beta-2-glycoprotein I in patients with antiphospholipid syndrome. Blood (2007) 110:4312–8.[Abstract/Free Full Text]
  35. Venugopal SK, Devaraj S, Jialal I. Macrophage conditioned medium induces the expression of C-reactive protein in human aortic endothelial cells: potential for paracrine/autocrine effects. Am J Pathol (2005) 166:1265–71.[Abstract/Free Full Text]
  36. Sun H, Koike T, Ichikawa T, et al. C-reactive protein in atherosclerotic lesions. Its origin and pathophysiological significance. Am J Pathol (2005) 167:1139–48.[Abstract/Free Full Text]
  37. Meek RL, Urieli-Shoval S, Benditt EP. Expression of apolipoprotein serum amyloid A mRNA in human atherosclerotic lesions and cultured vascular cells: implications for serum amyloid A function. Proc Natl Acad Sci USA (1994) 91:3186–90.[Abstract/Free Full Text]
  38. Aboyans V, Criqui MH, Denenberg JO, Knoke JD, Ridker PM, Fronek A. Risk factors for progression of peripheral arterial disease in large and small vessels. Circulation (2006) 113:2623–9.[Abstract/Free Full Text]
  39. Johnson BD, Kip KE, Marroquin OC, et al. Serum amyloid A as a predictor of coronary artery disease and cardiovascular outcome in women: the national heart, lung, and blood institute-sponsored women's ischemia syndrome evaluation (WISE). Circulation (2004) 109:726–32.[Abstract/Free Full Text]
  40. Erren M, Reinecke H, Junker R, et al. Systemic inflammatory parameters in patients with atherosclerosis of the coronary and peripheral arteries. Arterioscler Thromb Vasc Biol (1999) 19:2355–63.[Abstract/Free Full Text]
  41. Ames PRJ, Margarita A, Delgado Alves J, Tommasino C, Iannaccone L, Brancaccio V. Anticardiolipin antibody titre and plasma homocysteine independently predict intima-media thickness of carotid arteries in subjects with idiopathic antiphospholipid antibodies. Lupus (2002) 11:208–14.[Abstract/Free Full Text]
  42. Margarita A, Batuca J, Scenna G, et al. Subclinical atherosclerosis in primary antiphospholipid syndrome. Ann NY Acad Sci (2007) 1108:475–80.[CrossRef][Web of Science][Medline]
  43. Ames PRJ, Tommasino C, Alves J, et al. Antioxidant susceptibility of pathogenic pathways in subjects with antiphospholipid antibodies. A pilot study. Lupus (2000) 9:1–8.
  44. Zhou H, Wolberg AS, Roubey RA. Characterization of monocyte tissue factor activity induced by IgG antiphospholipid antibodies and inhibition by dilazep. Blood (2004) 104:2353–8.[Abstract/Free Full Text]
Submitted 26 June 2008; revised version accepted 29 August 2008.
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