LDLR and PCSK9 Are Associated with the Presence of Antiphospholipid Antibodies and the Development of Thrombosis in aPLA Carriers

Introduction The identification of the genetic risk factors that could discriminate non-thrombotic from thrombotic antiphospholipid antibodies (aPLA) carriers will improve prognosis of these patients. Several human studies have shown the presence of aPLAs associated with atherosclerotic plaque, which is a known risk factor for thrombosis. Hence, in order to determine the implication of atherosclerosis in the risk of developing thrombosis in aPLA positive patients, we performed a genetic association study with 3 candidate genes, APOH, LDLR and PCSK9. Material & Methods For genetic association study we analyzed 190 aPLA carriers -100 with non-thrombotic events and 90 with thrombotic events-and 557 healthy controls. Analyses were performed by chi(2) test and were corrected by false discovery rate. To evaluate the functional implication of the newly established susceptibility loci, we performed expression analyses in 86 aPLA carrier individuals (43 with thrombotic manifestations and 43 without it) and in 45 healthy controls. Results Our results revealed significant associations after correction in SNPs located in LDLR gene with aPLA carriers and thrombotic aPLA carriers, when compared with healthy controls. The most significant association in LDLR gene was found between SNP rs129083082 and aPLA carriers in recessive model (adjusted P-value = 2.55 x 10(-3); OR = 2.18; 95% CI = 1.49-3.21). Furthermore, our work detected significant allelic association after correction between thrombotic aPLA carriers and healthy controls in SNP rs562556 located in PCSK9 gene (adjusted P-value = 1.03 x 10(-2); OR = 1.60; 95% CI = 1.24-2.06). Expression level study showed significantly decreased expression level of LDLR gene in aPLA carriers (P-value < 0.0001; 95% CI 0.16-2.10; SE 0.38-1.27) in comparison to the control group. Discussion Our work has identified LDLR gene as a new susceptibility gene associated with the development of thrombosis in aPLA carriers, describing for the first time the deregulation of LDLR expression in individuals with aPLAs. Besides, thrombotic aPLA carriers also showed significant association with PCSK9 gene, a regulator of LDLR plasma levels. These results highlight the importance of atherosclerotic processes in the development of thrombosis in patients with aPLA.

The epitopes for some antiphospholipid antibodies are adducts of oxidized phospholipid and β2 glycoprotein 1 (and other proteins)

Circulating autoantibodies to phospholipids (aPLs), such as cardiolipin (CL), are found in patients with antiphospholipid antibody syndrome (APS). We recently demonstrated that many aPLs bound to CL only after it had been oxidized (OxCL), but not to a reduced CL analogue that could not undergo oxidation. We now show that the neoepitopes recognized by some aPLs consist of adducts formed between breakdown products of oxidized phospholipid and associated proteins, such as β2 glycoprotein 1 (β2GP1). Addition of human β2GP1, polylysine, native low-density lipoprotein, or apolipoprotein AI to OxCL-coated wells increased the anticardiolipin antibody (aCL) binding from APS sera that first had been diluted so that no aCL binding to OxCL could be detected. No increase in aCL binding was observed when these proteins were added to wells coated with reduced CL. The ability of β2GP1, polylysine, or low-density lipoprotein to be a “cofactor” for aCL binding to OxCL was greatly reduced when the proteins were methylated. Incubation of β2GP1 with oxidized 1-palmitoyl-2-linoleyl-[1-14C]-phosphatidylcholine (PC), but not with dipalmitoyl-[1-14C]-PC, led to formation of covalent adducts with β2GP1 recognized by APS sera. These data suggest that the reactive groups of OxCL, such as aldehydes generated during the decomposition of oxidized polyunsaturated fatty acids, form covalent adducts with β2GP1 (and other proteins) and that these are epitopes for aCLs. Knowledge that the epitopes recognized by many aPLs are adducts of oxidized phospholipid and associated proteins, including β2GP1, may give new insights into the pathogenic events underlying the clinical manifestations of APS.

Arterial disease and thrombosis in the antiphospholipid syndrome (APS): A pathogenic role for endothelin-1 (ET-1)

Objective To explore a possible correlation between endothelin 1 (ET-1), the most potent endothelium-derived contracting factor that modulates vascular smooth muscle tone, and arterial disease in patients with the antiphospholipid syndrome (APS). Methods Plasma levels of ET-1 were measured in APS patients with (n = 16) and without (n = 11) arterial thrombosis and in non-APS patients with arterial thrombosis (n = 9). In addition, steady-state prepro-ET-1 messenger RNA (mRNA) levels were determined in endothelial cells treated with a range of human monoclonal anticardiolipin antibodies (aCL) (as anti-β2-glycoprotein I antibodies) by semiquantitative 32P-dCTP-labeled reverse transcription-polymerase chain reaction. Results Compared with healthy controls, markedly increased plasma levels of ET-1 were found in APS patients with arterial thrombosis (2.00 ± 0.87 versus 0.96 ± 0.37 pg/ml; P = 0.0001) but not in other groups. Three human monoclonal aCL induced prepro-ET-1 mRNA levels significantly more than did control monoclonal antibody lacking aCL activity. Conclusion Plasma ET-1 levels correlated significantly with a history of arterial thrombosis in patients with APS. Prepro-ET-1 mRNA was induced by human monoclonal aCL in the in vitro experimental system. The induction of ET-1 by antiphospholipid antibodies might contribute to increased arterial tone, leading to vasospasm and, ultimately, to arterial occlusion.

Pediatric Antiphospholipid Syndrome: Clinical and Immunologic Features of 121 Patients in an International Registry

OBJECTIVES. The purpose of this study was to obtain data on the association of antiphospholipid antibodies with clinical manifestations in childhood and to enable future studies to determine the impact of treatment and long-term outcome of pediatric antiphospholipid syndrome.PATIENTS and METHODS. A European registry extended internationally of pediatric patients with antiphospholipid syndrome was established as a collaborative project of the European Antiphospholipid Antibodies Forum and Lupus Working Group of the Pediatric Rheumatology European Society. To be eligible for enrollment the patient must meet the preliminary criteria for the classification of pediatric antiphospholipid syndrome and the onset of antiphospholipid syndrome must have occurred before the patient's 18th birthday.RESULTS. As of December 1, 2007, there were 121 confirmed antiphospholipid syndrome cases registered from 14 countries. Fifty-six patients were male, and 65 were female, with a mean age at the onset of antiphospholipid syndrome of 10.7 years. Sixty (49.5%) patients had underlying autoimmune disease. Venous thrombosis occurred in 72 (60%), arterial thrombosis in 39 (32%), small-vessel thrombosis in 7 (6%), and mixed arterial and venous thrombosis in 3 (2%). Associated nonthrombotic clinical manifestations included hematologic manifestations (38%), skin disorders (18%), and nonthrombotic neurologic manifestations (16%). Laboratory investigations revealed positive anticardiolipin antibodies in 81% of the patients, anti-beta(2)-glycoprotein I antibodies in 67%, and lupus anticoagulant in 72%. Comparisons between different subgroups revealed that patients with primary antiphospholipid syndrome were younger and had a higher frequency of arterial thrombotic events, whereas patients with antiphospholipid syndrome associated with underlying autoimmune disease were older and had a higher frequency of venous thrombotic events associated with hematologic and skin manifestations.CONCLUSIONS. Clinical and laboratory characterization of patients with pediatric antiphospholipid syndrome implies some important differences between antiphospholipid syndrome in pediatric and adult populations. Comparisons between children with primary antiphospholipid syndrome and antiphospholipid syndrome associated with autoimmune disease have revealed certain differences that suggest 2 distinct subgroups. Pediatrics 2008; 122: e1100-e1107

The Ped-APS registry: The antiphospholipid syndrome in childhood

In recent years, antiphospholipid syndrome (APS) has been increasingly recognised in various paediatric autoimmune and nonautoimmune diseases, but the relatively low prevalence and heterogeneity of APS in childhood made it very difficult to study in a systematic way. The project of an international registry of paediatric patients with APS (the Ped-APS Registry) was initiated in 2004 to foster and conduct multicentre, controlled studies with large number of paediatric APS patients. The Ped-APS Registry is organised as a collaborative project of the European Forum on Antiphospholipid Antibodies and Juvenile Systemic Lupus Erythematosus Working Group of the Paediatric Rheumatology European Society. Currently, it documents a standardised clinical, laboratory and therapeutic data of 133 children with antiphospholipid antibodies (aPL)-related thrombosis from 14 countries. The priority projects for future research of the Ped-APS Registry include prospective enrolment of new patients with aPL-related thrombosis, assessment of differences between the paediatric and adult APS, evaluation of proinflammatory genotype as a risk factor for APS manifestations in childhood and evaluation of patients with isolated nonthrombotic aPL-related manifestations. © The Author(s), 2009.

Systemic sclerosis sine scleroderma associated with antiphospholipid syndrome

The antiphospholipid syndrome (APS) can be primary, when it occurs alone, or secondary, when it is associated with another autoimmune disease, mainly systemic lupus erythematosus and rarely other autoimmune diseases. Cases described in literature (Medline 1966 to December 2009) associate the presence of antiphospholipid antibodies with the presence of APS and systemic sclerosis (SS). Currently, however, no cases of the SS variant sine scleroderma with APS have been described. In this study, the authors describe the case of a patient with APS characterised by thrombosis of the retinal veins, in May 2006, the presence of lupus anticoagulant and an anticardiolipin IgG antibody. In May 2007, this patient developed Raynaud's phenomenon, a lack of oesophageal motility and nailfold capillaroscopy with a scleroderma pattern. The patient was positive for the anti-centromere antibody but lacked any evidence of cutaneous thickening or involvement. In summary, the authors describe the first case of a patient with APS associated with SS sine scleroderma.

Chorea in primary antiphospholipid syndrome is associated with rheumatic fever

The aim of the study is to evaluate the frequency of chorea in a cohort of primary antiphospholipid syndrome (PAPS) patients and their possible clinical and laboratory associations. The records of 88 PAPS patients, fulfilling Sapporo criteria, followed up at the rheumatology outpatient clinic, were analyzed in order to determine the frequency of chorea. Risk factors for chorea, clinical manifestations, associated comorbidities, serologic features and treatment strategies were analyzed. Eighty-eight PAPS patients were evaluated. Mean age was 40.6 +/- A 11.1 years, and 91% of them were Caucasian and 91% women. Four (4.5%) patients with chorea were identified: 2 of them (50%) had only one chorea episode and 2 (50%) had recurrent chorea. All patients had chorea onset before PAPS diagnosis. Mean age, gender and ethnical distribution were comparable in groups with or without seizures (P > 0.05). Interestingly, the comparison of the 4 PAPS patients with chorea with those without this abnormality (n = 84) demonstrated a lower BMI [21.1 (18-24.2) vs. 27.5 (17.5-40.9) kg/m(2), P = 0.049] and frequency of venous events (0 vs. 63.1%, P = 0.023) in the first group. A higher frequency of rheumatic fever (75% vs. 0, P < 0.001) and thrombocytopenia (75 vs. 21.4%, P = 0.041) was observed in PAPS individuals with chorea. Both groups were alike regarding the other clinical APS manifestations, disease duration, risk factors for cerebrovascular diseases, use of drugs and antiphospholipid antibodies (P > 0.05). This study demonstrated that 4.5% of PAPS patients had chorea, predominately before PAPS diagnosis, and this neurological abnormality was associated with rheumatic fever and thrombocytopenia. These data reinforce the need for RF diagnosis in those PAPS patients with chorea.

Moderate/severe erectile dysfunction in patients with antiphospholipid syndrome

Purpose: To evaluate sexual function of antiphospholipid syndrome (APS) patients using the Brazilian version of the validated International Index of Erectile Function (IIEF). Materials and methods: Eleven APS male patients (Sapporo criteria) were age and race-matched with 22 healthy controls. Demographic and clinical data, drug use and antiphospholipid antibodies were evaluated. The IIEF was also self-applied. Results: Mean age (p = 0.114), frequency of Caucasian race (p = 1.00) and married status (p = 0.438) were similar in APS and controls. Mean disease duration was 8.8 +/- 4.6 years. Erectile dysfunction (ED) was frequently observed in APS versus controls (45.5 vs. 4.5%, p = 0.0096), especially moderate/severe ED (p = 0.0081). The total IIEF score (49.6 vs. 67.1, p = 0.019), erectile function (19.6 vs. 28.1, p = 0.005) and intercourse satisfaction (7.8 vs. 11.9, p = 0.009) were lower in patients than in controls. No differences were seen in orgasmic function (p = 0.114), sexual desire (p = 0.123) or overall satisfaction (p = 0.097) between the groups. The comparison between APS patients with ED (n = 5) and without ED (n = 6) revealed more arterial events in APS with ED (100 vs. 16.7%, p = 0.0152), and also longer disease duration (12 [7-16] vs. 5.5 [2-13] years, p = 0.031). A trend towards lower venous events (20 vs. 83.3%, p = 0.0801) and higher renal thrombotic microangiopathy (60% vs. 0, p = 0.0606) was observed in APS patients with ED. Demographics, clinical manifestations, smoking and antiphospholipid antibodies positivity were similar in both groups. Conclusion: To our knowledge, this was the first study that demonstrated moderate/severe ED in almost 50% of cases of a rare autoimmune disease. This alteration was linked to arterial events and longer disease duration. Lupus (2012) 21, 319-323.

Seizures in Primary Antiphospholipid Syndrome: The Relevance of Smoking to Stroke

Objectives. To evaluate the frequency of seizures in primary antiphospholipid syndrome (PAPS) and their possible clinical and laboratory associations. Methods. Eighty-eight PAPS patients (Sydney's criteria) were analyzed by a standard interview, physical examination and review of medical charts. Risk factors for seizures, clinical manifestations, associated comorbidities, and antiphospholipid antibodies were evaluated. Results. Nine (10.2%) patients with seizures were identified, 77.8% had convulsions onset after PAPS diagnosis. Mean age, gender, and race were comparable in groups with or without seizures. Interestingly, a higher frequency of current smoking (44.4 versus 10.1%, P = 0.019) was observed in the first group. Stroke, Sneddon's syndrome, and livedo reticularis were more frequent in PAPS patients with seizures than those without seizures, although not statistically significant (P > 0.05). Comparison between patients with seizures onset after PAPS diagnosis (n = 7) and those without convulsions (n = 79) demonstrated a higher frequency of current smoking (42.9 versus 10%, P = 0.042) and stroke in the first group (71.4 versus 30.4%, P = 0.041). Regression analysis confirmed that smoking (P = 0.030) and stroke (P = 0.042) were independently associated to seizures. Conclusion. About 10.2% of PAPS patients had convulsions, predominantly after PAPS diagnosis, and seizures were associated to current smoking and stroke.

Signaltransduktion von IgG-Antiphospholipid-Antikörpern in plasmazytoiden Dendriten und Monomac1 Zellen

Das Antiphospholipid-Syndrom (APS) ist eine Autoimmunerkrankung die sich durch venöse und arterielle Thrombosen und/oder Spontanaborte bei gleichzeitigem Nachweis von persistierenden, erhöhten Antiphospholipid-Antikörper (aPL)-Titern charakterisieren lässt. Die zugrunde liegenden Mechanismen, über die aPL Pathogenität vermitteln, sind bislang wenig verstanden. Im Rahmen dieser Arbeit konnte gezeigt werden, dass drei humane monoklonale IgG aPL sowie IgG Fraktionen von APS Patienten eine Überexpression von TLR7 und TLR8 in plasmazytoiden dendritischen Zellen bzw. monozytären Zellen induzieren. Gleichzeitig erfolgt die Induktion der TLR7/8 Translokation vom endoplasmatischen Retikulum (ER) ins Endosom. Diese Effekte werden durch die Internalisierung der aPL und die nachfolgende Aktivierung einer NADPH Oxidase sowie durch endosomale Superoxid Produktion vermittelt. Als Folge dessen werden die Zellen extrem für TLR7/8 Liganden sensibilisiert. Diese Beobachtungen beschreiben einen neuen Signalmechanismus der innaten Immunität, der seinen Ursprung im Endosom nimmt. Da die Überexpression von TLR7 auch in pDCs von APS Patienten detektiert werden konnte, bieten unsere Ergebnisse eine Erklärung für die proinflammatorischen und prokoagulanten Effekte von aPL. rnWeiterhin führte die kombinierte Stimulation mit aPL und TLR7 Liganden in pDCs zu einem signifikant verstärkten Potential zur CD4+ Th2 Zell Aktivierung bzw. zur Regulation der B-Zell Differenzierung und Immunglobulin Produktion. Die Anwesenheit der pDCs erhöhte dabei synergistisch die CD40/86 Expression, die Proliferation sowie die Plasmazell-Differenzierung von isolierten peripheren B-Zellen, die mit aPL und TLR Liganden stimuliert wurden. Dieser Stimulationsansatz war außerdem ausreichend um naive B-Zellen zur IgM/IgG Produktion anzuregen und die Synthese neuer IgG aPL durch Gedächtnis-B-Zellen einzuleiten. Die Beteiligung der pDCs an diesem Prozess erfolgte durch Zytokin Sekretion sowie direktem Zell-Zell-Kontakt. Die Anwesenheit von Th2-Helferzellen war dabei nicht obligatorisch, konnte jedoch die B-Zell Aktivierung zusätzlich fördern. Eine Hochregulierung von TLR7 oder TLR9 innerhalb der B-Zell Population war nicht involviert. rnrnDiese Ergebnisse zeigen erstmalig die Relevanz einer pDC Aktivierung im Hinblick auf die Aufrechterhaltung der pathogenen Aktivität im Rahmen des APS. Da eine Dysregulierung von TLR7 bereits als ursächlich für die Ausbildung einer systemischen Autoimmunität erachtet wird, sollten unsere Ergebnisse für das generelle Verständnis von Autoimmunität von großer Relevanz sein.rn

A monoclonal IgG anticardiolipin antibody from a patient with the antiphospholipid syndrome is thrombogenic in mice.

Antiphospholipid antibodies, including anticardiolipin antibodies (ACA), are strongly associated with recurrent thrombosis in patients with the antiphospholipid syndrome (APS). To date, reports about the binding specificities of ACA and their role(s) in causing and/or sustaining thrombosis in APS are conflicting and controversial. The plasmas of patients with APS, usually containing a mixture of autoantibodies, vary in binding specificity for different phospholipids/cofactors and vary in in vitro lupus anticoagulant activity. Although in vivo assays that allow assessment of the pathogenic procoagulant activity of patient autoantibodies have recently been developed, the complex nature of the mixed species prevented determination of the particular species responsible for in vivo thrombosis. We have generated two human IgG monoclonal ACA from an APS patient with recurrent thrombosis. Both bound to cardiolipin in the presence of 10% bovine serum, but not in its absence, and both were reactive against phosphatidic acid, but were nonreactive against purified human beta-2 glycoprotein 1, DNA, heparan sulfate, or four other test antigens. Both monoclonal autoantibodies lacked lupus anticoagulant activity and did not inhibit prothrombinase activity. Remarkably, one of the monoclonal antibodies has thrombogenic properties when tested in an in vivo mouse model. This finding provides the first direct evidence that a particular antiphospholipid antibody specificity may contribute to in vivo thrombosis.

EULAR Recommendations for Women's Health and the Management of Family Planning, Assisted Reproduction, Pregnancy and Menopause in Patients with Systemic Lupus Erythematosus and/or Antiphospholipid Syndrome

OBJECTIVES: Develop recommendations for women's health issues and family planning in systemic lupus erythematosus (SLE) and/or antiphospholipid syndrome (APS). METHODS: Systematic review of evidence followed by modified Delphi method to compile questions, elicit expert opinions and reach consensus. RESULTS: Family planning should be discussed as early as possible after diagnosis. Most women can have successful pregnancies and measures can be taken to reduce the risks of adverse maternal or fetal outcomes. Risk stratification includes disease activity, autoantibody profile, previous vascular and pregnancy morbidity, hypertension and the use of drugs (emphasis on benefits from hydroxychloroquine and antiplatelets/anticoagulants). Hormonal contraception and menopause replacement therapy can be used in patients with stable/inactive disease and low risk of thrombosis. Fertility preservation with gonadotropin-releasing hormone analogues should be considered prior to the use of alkylating agents. Assisted reproduction techniques can be safely used in patients with stable/inactive disease; patients with positive antiphospholipid antibodies/APS should receive anticoagulation and/or low-dose aspirin. Assessment of disease activity, renal function and serological markers is important for diagnosing disease flares and monitoring for obstetrical adverse outcomes. Fetal monitoring includes Doppler ultrasonography and fetal biometry, particularly in the third trimester, to screen for placental insufficiency and small for gestational age fetuses. Screening for gynaecological malignancies is similar to the general population, with increased vigilance for cervical premalignant lesions if exposed to immunosuppressive drugs. Human papillomavirus immunisation can be used in women with stable/inactive disease. CONCLUSIONS: Recommendations for women's health issues in SLE and/or APS were developed using an evidence-based approach followed by expert consensus.

Variability in the international normalised ratio (INR) in patients with antiphospholipid syndrome and positive lupus anticoagulant: should the INR targets be higher?

El síndrome antifosfolípido es un desorden autoinmune caracterizado por hipercoagulabilidad que requiere terapia anticoagulante como pilar fundamental, siendo la warfarina el tratamiento de elección en los casos que requieren manejo por largos periodos. Sin embargo, los pacientes con anticoagulante lúpico positivo representan un reto porque tienen mayor riesgo de presentar eventos trombóticos, sumado a que el seguimiento con el International Normalized Ratio (INR) no es confiable, ya que estos anticuerpos generan interferencia con las pruebas de laboratorio basadas en fosfolípidos, como es el caso del tiempo de protrombina (PT) con INR basal prolongado, incluso antes del inicio de la terapia anticoagulante. Por tal razón, se ilustra el caso de una paciente con síndrome antifosfolípido primario y anticoagulante lúpico positivo quien ha presentado múltiples episodios trombóticos, a pesar de recibir terapia anticoagulante. Además se hace una revisión de la literatura disponible y se postulan nuevas metas de INR en estos pacientes diferentes de las que se plantean actualmente.

Lupus Myelopathy in a Child

A 5-year-old female developed, after a 7-month period of fever, anorexia, weight loss, and a transitory cutaneous erythematous eruption, a severe acute transverse myelopathy, with a partial recovery of motor and sensory function. She had positive antinuclear and antidouble-stranded DNA antibodies but no antiphospholipid antibodies. Six months later she had massive proteinuria and restarted treatment with steroids and cyclophosphamide. Our patient is one of the youngest reported with lupus myelopathy. We discuss the clinical presentation, the magnetic resonance imaging findings, and other relevant laboratory studies of this rare but serious complication of systemic lupus erythematosus.