Although antiphospholipid antibodies (aPL) are associated with thrombosis, it is not known who with aPL is at higher risk for thrombosis. It was the aim of this cross-sectional study to investigate how thrombophilic factors contribute to venous or arterial thrombosis in aPL-positive individuals. In outpatient test centres at two tertiary care hospitals, two hundred and eight (208) persons requiring aPL testing were matched by age, gender and centre to 208 persons requiring a complete blood count. Persons were classified as aPL-positive (having anticardiolipin, lupus anticoagulant and/or anti-β2-glycoprotein I antibodies) or aPL-negative. Several thrombophilic factors were studied using logistic regression modelling. Results showed that the aPL-positive group had three-fold more events (37%) than the aPL-negative group (12%). In unadjusted analyses, clinically important associations were observed between factor V Leiden and venous thrombosis, hyperhomocysteinemia and arterial thrombosis, and activated protein C resistance (APCR) and venous thrombosis (OR, 95% CI = 4.00, 1.35–11.91; 4.79, 2.03–11.33; and 2.03, 1.03–3.97, respectively). After adjusting for recruitment group, persons with both APCR and aPL had a three-fold greater risk (OR, 95% CI = 3.31, 1.30–8.41) for venous thrombosis than those with neither APCR nor aPL. Similarly, after adjusting for hypertension, family history of cardiovascular disease, gender and recruitment group, persons with both hyperhomocysteinemia and aPL had a five-fold increased risk (OR, 95% CI = 4.90, 1.37–17.37) for arterial thrombosis compared to those with neither risk factor. In conclusion, APCR phenotype and hyperhomocysteinemia are associated with a higher risk of venous and arterial thrombosis, respectively, in the presence of aPL.
PMID: 15583739 CAMSID: cams2359
Antiphospholipid antibodies; antiphospholipid syndrome; thrombosis; activated protein C resistance; hyperhomocysteinemia
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.
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.
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.
Lupus Erythematosus, Systemic; Antiphospholipid Antibodies; Lupus Anticoagulant; Hydroxychloroquine
Objective: To determine the stability and the degree of variation of antiphospholipid antibody (aPL) results over time in a large cohort of well evaluated aPL positive patients; and to analyse factors contributing to aPL variation and the validity of aPL in a real world setting in which aPL tests are done in multiple laboratories.
Methods: The clinical characteristics, drug treatment, and 1652 data points for lupus anticoagulant (LA), anticardiolipin antibodies (aCL), and anti-ß2 glycoprotein I antibodies (anti-ß2GPI) were examined in 204 aPL positive patients; 81 of these met the Sapporo criteria for antiphospholipid syndrome (APS) and 123 were asymptomatic bearers of aPL.
Results: 87% of initially positive LA results, 88% of initially negative to low positive aCL results, 75% of initially moderate to high positive aCL results, 96% of initially negative to low positive anti-ß2GPI results, and 76% of initially moderate to high positive anti-ß2GPI results subsequently remained in the same range regardless of the laboratory performing the test. Aspirin, warfarin, and hydroxychloroquine use did not differ among patients whose aCL titres significantly decreased or increased or remained stable. On same day specimens, the consistency of aCL results among suppliers ranged from 64% to 88% and the correlation ranged from 0.5 to 0.8. Agreement was moderate for aCL IgG and aCL IgM; however, for aCL IgA agreement was marginal.
Conclusions: aPL results remained stable for at least three quarters of subsequent tests, regardless of the laboratory performing the test; the small amount of variation that occurred did not appear to be caused by aspirin, warfarin, or hydroxychloroquine use.
Conventional risk factors for coronary artery disease fail to explain the increased frequency or cardiovascular morbidity in systemic lupus erythematosus (SLE) patients. This study was conducted to determine the possible influence of autoimmune and inflammatory phenomena markers on coronary artery calcifications and myocardial perfusion abnormalities in SLE patients.
Materials and methods
Multi-detector computed tomography (MDCT)-based coronary calcium scoring and single photon emission computerized tomography (SPECT) studies (Tc-99m sestamibi) were performed in 60 SLE patients in stable clinical condition, without a prior history of coronary artery disease. Laboratory evaluation included serum C-reactive protein (CRP), complement C3c and C4 components and antiphospholipid antibodies (aPL). The latter included anticardiolipin (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies, of both IgG and IgM classes, and lupus anticoagulant (LA) in plasma.
SPECT revealed persistent perfusion defects in 22 (36.7%) patients and exercise-induced defects in eight (13.3%), while MDCT revealed coronary calcifications in 15 (25%). Calcium scores ranged from 1 to 843.2 (mean 113.5 ± 259.7). No association was found between conventional coronary artery disease risk factors (obesity, hypertension, tobacco use, hyperlipidaemia, diabetes) nor CRP, C3c or C4 levels and coronary calcifications or myocardial perfusion defects. On the contrary, in patients with these pathologies, augmented autoimmunization was found, reflected by increased aCL IgG and antiβ2GPI IgG levels. In patients with aCL IgG >20 RU/ml or antiβ2GPI IgG >3 RU/ml, the relative risk of coronary calcification formation was 4.1 compared to patients with normal values. Accordingly, in LA-positive patients the relative risk of coronary calcification formation was 4.4 compared to LA-negative patients.
Conventional risk factors for coronary artery disease as well as markers of an ongoing inflammation did not show any association with perfusion defects and/or coronary artery calcifications in SLE patients. On the contrary, calcified atherosclerotic plaques and myocardial perfusion defects were observed mainly in patients with elevated levels of anticardiolipin and aβ2GPI antibodies of the IgG class. It might be speculated that coronary artery calcifications and perfusion defects are a result of antiphospholipid antibodies-induced coronary artery microthrombosis.
Systemic lupus erythematosus; Autoimmune diseases; Coronary calcification; Atherosclerosis; MDCT; SPECT; Perfusion scintigraphy
Objective: To examine the hypothesis that testing for new antiphospholipid antibody specificities may help to identify the antiphospholipid syndrome (APS) in patients with systemic lupus erythematosus (SLE) with thrombosis who are repeatedly negative for anticardiolipin antibodies (aCL) and/or lupus anticoagulant (LA).
Methods: Three groups of patients with SLE were studied: (a) SLE/APS (n = 56): 51 female, mean (SD) age 46 (11) years, fulfilling 1999 Sapporo criteria for the APS; (b) SLE/thrombosis (n = 56): 53 female, age 42.6 (12) years, all with a history of thrombosis and persistently negative for aCL and/or LA; (c) SLE only (n = 56): 53 female, age 40 (11) years, without a history of thrombotic events. aCL and LA were retested in all samples. All patients were tested for anti-ß2-glycoprotein I (anti-ß2GPI) and antiprothrombin antibodies (aPT) by coating prothrombin on irradiated plates or using phosphatidylserine-prothrombin complex as the antigen (aPS-PT).
Results: Anti-ß2GPI were only present in patients from the SLE/APS group, all of whom were also positive for aCL. aPT and aPS-PT were also more commonly found in SLE/APS than in SLE/thrombosis or SLE only groups (54% v 5%, p<0.0001 or v 16%, p<0.0001 for aPT and 63% v 2%, p<0.0001 or v 11%, p<0.0001 for aPS-PT, respectively). No differences were found between SLE/thrombosis and SLE only groups (p = 1.5 for ß2GPI, p = 0.1 for aPT, and p = 0.1 for aPS-PT).
Conclusion: Testing for aPT in patients with SLE with thrombosis, but persistently negative for aCL and LA, may be helpful in some selected cases. Anti-ß2GPI are not present in patients who are negative for aCL.
Currently, 3 antiphospholipid assays are widely used clinically [lupus anticoagulant (LAC), anticardiolipin (aCL), and anti-β2-glycoprotein I (anti-β2-GPI)]. LAC is the most specific assay, conferring the highest risk of thrombosis and pregnancy loss, but it cannot be validly performed in an anticoagulated patient. We investigated the usefulness of antiphosphatidyl-serine/prothrombin (anti-PS/PT) and its association with thrombosis. Anti-PS/PT is strongly associated with the presence of LAC. We also studied the association of IgA antiphospholipid isotypes and specific domains of β2-GPI with thrombosis in systemic lupus erythematosus (SLE).
Stored samples from patients with SLE, with and without past thrombosis, were assayed for antibodies to the whole β2-GPI protein (IgG/IgM/IgA), to β2-GPI domain 1 (IgG), to β2-GPI domain 4/5 (IgA), aCL (IgG/IgM/IgA), and anti-PS/PT (IgG, IgM, and IgG/M). LAC was detected using the dilute Russell’s viper venom time (dRVVT) with confirmatory testing.
Anti-PS/PT IgG and IgG/M and anti-β2-GPI IgG, IgM, and IgA were highly associated with a history of LAC by dRVVT (p < 0.0001). For all thrombosis, of the traditional ELISA assays, anti-β2-GPI IgA, IgG, and aCL IgA were most associated. Anti-PS/PT IgG and IgG/M had a similar magnitude of association to the traditional ELISA. For venous thrombosis, of the traditional ELISA, anti-β2-GPI (IgG and IgA), anti-PS/PT (IgG and IgG/M), and aCL IgA were associated. Again, anti-PS/PT (IgG and IgG/M) had the same magnitude of association as the traditional ELISA. For stroke, significant association was seen with anti-β2-GPI IgA D4/5.
In anticoagulated patients, where LAC testing is not valid, anti-PS/PT, either IgG or IgG/IgM, might serve as useful alternative tests to predict a higher risk of thrombosis. Anti-PS/PT antibodies were associated with all thrombosis and with venous thrombosis. IgA isotypes in secondary antiphospholipid syndrome are associated with thrombosis. Anti-β2-glycoprotein domain 1 was not shown to be associated with thrombosis in SLE.
ANTI-PHOSPHATIDYLSERINE/PROTHROMBIN; ANTI-β2-GLYCOPROTEIN I; DOMAIN 4/5 IgA; ANTICARDIOLIPIN
Antiphospholipid syndrome (APLS) is characterized by thrombocytopenia, thromboembolic phenomena, and recurrent fetal loss, associated with anticardiolipin antibodies (ACA) and/or lupus anticoagulant. The syndrome may be primary or may be associated with other conditions such as systemic lupus erythematosus. We have previously shown the ability to induce APLS in naive mice following passive transfer of serum and monoclonal ACAs. Similarly we generated the secondary APLS in BALB/c mice following immunization with a pathogenic anti-DNA antibody. In the current study we report on the induction of primary APLS following immunization of BALB/c mice with a human monoclonal ACA (H-3). The mice developed high persistent titers of ACA. The APLS was characterized by prolonged activated partial thromboplastin time, low fecundity rate (21% vs. 48% of control immunized mice), high resorption index of fetuses (25% vs. 3%), and low weights of embryos and placentae. Our study points to the ability of inducing primary APLS in naive mice. The induction of various presentations of APLS by different ACA may explain the diversity of clinical manifestations seen in patients with APLS.
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.
PMID: 16510527 CAMSID: cams2311
Antiphospholipid antibodies; Anticardiolipin antibodies; Lupus anticoagulant; Anti-β2-glycoprotein I antibodies
Which serologic and clinical findings predict adverse pregnancy outcome (APO) in patients with antiphospholipid antibody (aPL) is controversial.
PROMISSE is a multicenter, prospective observational study of risk factors for APO in patients with aPL (lupus anticoagulant [LAC], anticardiolipin antibody [aCL] and/or antibody to β2 glycoprotein I [anti-β2-GP-I]). We tested the hypothesis that a pattern of clinical and serological variables can identify women at highest risk for APO.
Between 2003 and 2011 we enrolled 144 pregnant patients, of whom 28 had APO. Thirty-nine percent of patients with LAC had APO, compared to 3% who did not have LAC (p < 0.0001). Only 8% of women with IgG aCL ≥40 u/mL but not LAC suffered APO, compared to 43% of those with LAC (p = 0.002). IgM aCL or IgG or IgM anti-β2-GP-I did not predict APO. In bivariate analysis, APO occurred in 52% of patients with and 13% of patients without prior thrombosis (p = 0.00005), and in 23% with SLE compared to 17% without SLE (not significant); SLE was a predictor in multivariate analysis. Prior pregnancy loss did not predict APO, nor did maternal race. Simultaneous aCL, anti-β2-GP-I, and LAC did not predict APO better than did LAC alone.
LAC is the primary predictor of APO after 12 weeks gestation in aPL-associated pregnancies. ACL and anti-β2-GP-I, if LAC is not also present, do not predict APO.
The antiphospholipid (APS or Hughes') syndrome, anticardiolipin antibodies (aCL), and the lupus anticoagulant (LA) are associated with systemic lupus erythematosus, malignancy, infection, and drugs. It has been described in patients with primary systemic vasculitis (PSV).
To determine the prevalence of APS in patients with PSV attending a vasculitis clinic and the prevalence of patients with positive aCL and/or the LA who do not fulfil the classification criteria for APS.
All case notes of patients attending the vasculitis clinic over a 12 month period were reviewed. Outpatients and inpatients were both included and were assessed for features of the APS and presence of aPL. Patients with positive aCL or LA tests were classified according to the significance of these results.
Of 144 patients with PSV, 25 had positive aCL or LA on at least one occasion, representing a point prevalence of 17%. Of these, nine had definite APS (classified by the Sapporo criteria) and a further four patients had clinical and serological features of APS, although insufficient to satisfy the Sapporo criteria. Twelve had only positive aPL.
The antiphospholipid syndrome, aCL, and the LA may occur in association with PSV.
antiphospholipid antibodies; systemic vasculitis; Hughes' syndrome
Persistent levels of antiphospholipid (aPL) antibodies [lupus anticoagulant (LA), anticardiolipin (aCL), anti-beta 2 glycoprotein I (aβ2GPI) IgG and/or IgM] in association with clinical features of thrombosis and/or pregnancy associated morbidity are indicative of antiphospholipid syndrome (APS). Of the aPL antibodies, aCL is the most sensitive for APS, however, their lack of specificity constitute a laboratory and clinical challenge. IgG/IgM antibodies directed against APhL (a mixture of phospholipids) has been reported to predict APS more reliably than aCL tests. The main objective of this study was to evaluate the performance characteristics of the APhL IgG/IgM ELISA, relative to the aCL and aβ2GPI tests.
Sixteen (16) clinically confirmed APS and 85 previously tested serum (PTS) samples for aCL and aβ2GPI IgG/IgM antibodies were evaluated with the APhL IgG/IgM ELISA. Clinical specificity was determined in 100 serum samples (50 healthy and 50 infectious disease controls [parvo- and syphilis-IgG/IgM positive]).
The IgG antibody prevalence for aCL and APhL in the APS and PST groups was comparable with marginal differences in clinical specificities. In contrast to the aCL IgM ELISA, the APhL test showed improved clinical specificities (72% aCL vs 94% APhL in the healthy controls; 38% aCL vs 78% APhL in the infectious disease controls) with implications for increased reliability in the diagnosis of APS. The overall agreement of the APhL with the aCL or aβ2GPI for the IgG tests was 89% and 85% respectively, and that of the APhL IgM to the aCL or aβ2GPI IgM tests was 72% and 86% respectively.
Routine use of the APhL IgG/IgM ELISA may substantially reduce the high number of false positives associated with the aCL test without loss in sensitivity for APS.
Anticardiolipin; APhL; antiphospholipid antibodies; method comparison
(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.
patent foramen ovale; anti-phospholipid antibodies; cardiac valve thickening; stroke recurrence risk; stroke risk factors; Risk Factors
BACKGROUND—Avascular necrosis of bone (AVN) is a well known complication in patients with systemic lupus erythematosus (SLE).
OBJECTIVE—To investigate the role of antiphospholipid antibody status (IgM and IgG anticardiolipin antibodies and lupus anticoagulant) with adjustment for corticosteroid use as risk factors for the development of AVN.
METHODS— A cohort of 265 patients receiving long term follow up in our SLE clinic from 1978 to 1998 was analysed. Patients with AVN complications were detected and then matched for age, sex, ethnicity, duration of disease, and organ disease with two other patients with SLE. A further 31 patients were chosen at random for the analysis.
RESULTS—Eleven patients had AVN, giving a point prevalence of 4%. There were no significant differences demonstrable in the presence of individual antiphospholipid antibodies (aPL) or their combination between the group with AVN or the two control groups.
CONCLUSION—Incorporating an adjustment for corticosteroid use we were unable to show a link between the presence of aPL and the development of AVN in patients with SLE.
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.
PMID: 20353968 CAMSID: cams2352
antiphospholipid syndrome; β2-glycoprotein I; heat shock protein 60; innate immunity; lipopolysaccharide; toll-like receptor ligands
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.
Antibodies, anticardiolipin; Antiphospholipid syndrome; Purpura, thrombocytopenic, idiopathic; Lupus coagulation inhibitor; Thrombosis
Antiphospholipid syndrome (APS) is primarily considered to be an autoimmune pathological condition that is also referred to as "Hughes syndrome". It is characterized by arterial and/or venous thrombosis and pregnancy pathologies in the presence of anticardiolipin antibodies and/or lupus anticoagulant. APS can occur either as a primary disease or secondary to a connective tissue disorder, most frequently systemic lupus erythematosus (SLE). Damage to the nervous system is one of the most prominent clinical constellations of sequelae in APS and includes (i) arterial/venous thrombotic events, (ii) psychiatric features and (iii) other non-thrombotic neurological syndromes. In this overview we compare the most important vascular ischemic (occlusive) disturbances (VIOD) with neuro-psychiatric symptomatics, together with complete, updated classifications and hypotheses for the etio-pathogenesis of APS with underlying clinical and laboratory criteria for optimal diagnosis and disease management.
Antiphospholipid syndrome; antiphospholipid antibodies; ischemic; occlusive; neurological; classifications; etio-pathogenesis; criteria
OBJECTIVE--To investigate whether beta 2-glycoprotein I antibody (aGPI) exists in sera that are positive for antiphospholipid antibodies (aPL). METHODS--Thirty six patients with systemic lupus erythematosus (SLE) and 20 healthy volunteers were recruited. GPI independent and dependent aPL (anticardiolipin (aCL), antiphosphatidylserine, antiphosphatidylinositol, antiphosphatidic acid) were measured using a conventional enzyme linked immunosorbent assay (ELISA). aGPI was measured by an ELISA using a gamma irradiated plate coated with purified GPI. RESULTS--Twenty of 36 SLE patients were positive for at least one of the GPI-dependent aPL. Five of these 20 were also positive for aGPI. Another five of the 20 showed low GPI dependency aCL antibodies; however, three of these patients required GPI for binding to phosphatidylserine, phosphatidylinositol, or both. CONCLUSION--We confirmed the existence of aGPI in patients with true GPI dependent aPL. From these results, we recommend the use of a gamma irradiated plate with GPI as antigen for the detection of true GPI dependent aPL or aGPI.
Many infections are associated with antiphospholipid antibodies (aPLs). The purpose of this study was to investigate the prevalence, persistence, clinical significance, and characteristics of aPLs in hepatitis B virus (HBV)-infected patients.
This study included 143 patients with HBV infection and 32 healthy individuals as controls. The presence of anticardiolipin antibodies (aCL Ab), anti-β2-glycoprotein I antibodies (β2GPI Ab), and lupus anticoagulant (LA) was assessed.
The total prevalence of aPLs in HBV-infected patients was 12.6% (18 of 143). Of these 18 patients, 15 had low to medium titers of aCL Ab (10 with IgM, 4 with IgG, and 1 with both isotypes). β2GPI Ab and LA were detected in 3 (2.1%) and 2 (1.4%) patients with HBV infection, respectively. In follow-up specimens from 14 patients with elevated levels of aCL Ab or β2GPI Ab, 10 (71.4%) showed the persistent presence of aPLs. No clinical manifestations related to aPLs were identified.
In HBV-infected patients, the most frequently detected antiphospholipid antibodies were IgM aCL Ab, which have a weak association with the clinical manifestations of APS. Unlike the transient presence reported for other infection-associated aPLs, most aPLs were persistently detected over a 12-week period in patients with HBV infection.
Anticardiolipin antibodies; Anti-β2-glycoprotein I antibodies; Lupus coagulation inhibitor; Hepatitis B virus
Few studies have examined thrombosis in systemic lupus erythematosus (SLE), none have included Asian-Americans, and most have had small sample sizes. We analysed risk factors for thrombosis in a large, multiethnic SLE cohort.
We studied 1930 SLE subjects, including Caucasians, African-Americans, Asian-Americans and Hispanics. Data were derived from questionnaires and medical records. Documented history of thrombosis was the primary outcome. Explanatory variables included age at SLE diagnosis, gender, ethnicity, disease duration, smoking, antiphospholipid antibody (aPL) status, nephritis and specific medications.
Smoking (OR 1.26, p = 0.011), longer disease duration (OR 1.26 per 5 years p = 0.027×10-7), nephritis (OR 1.35, p = 0.036), aPL positivity (OR 3.22, p<10-9) and immunomodulating medication use (OR 1.40, p = 0.011) were statistically significant risk factors for thrombosis. Younger age at SLE onset was protective (OR 0.52 for age ≤20, p = 0.001). After adjusting for disease severity and incorporating propensity scores, hydroxychloroquine use remained significantly protective for thrombosis (OR 0.62, p = 4.91×10-4).
This study confirms that older age at onset, longer disease duration, smoking, aPL positivity, history of nephritis and immunomodulating medication use are risk factors for thrombosis in SLE. These data are the first to confirm in a large and ethnically diverse SLE cohort that hydroxychloroquine use is protective for thrombosis.
Antiphospholipid syndrome is a multisystem autoimmune disease characterized by arterial and/or venous thrombosis and persistent presence of antiphospholipid antibodies. It can be a primary disease or secondary when associated with other autoimmune diseases.
We present a case of a 16-year-old Caucasian boy with a massive arterial and venous thrombosis in his lower limbs as well as in his central nervous system with clinical symptoms such as headaches and chorea. He did not present any clinical or laboratory signs of a systemic inflammatory connective tissue disease, including systemic lupus erythematosus. Based on the clinical picture and results of the diagnostic tests (positive antibodies against β2-glycoprotein and a high titre of anticardiolipin antibodies) we finally diagnosed primary antiphospholipid syndrome. During a 9-month follow up after the acute phase of the disease, he was treated with low-molecular-weight heparin. Neurological symptoms were relieved. Features of recanalization in the vessels of his lower limbs were observed. After a subsequent 6 months, because of the failure of preventive treatment – an incident of thrombosis of the vessels of his testis – treatment was modified and heparin was replaced with warfarin.
Although the preventive treatment with warfarin in our patient has continued for 1 year of follow up without new symptoms, further observation is needed.
Antiphospholipid syndrome; Arterial thrombosis; Systemic lupus erythematosus; Venous thrombosis
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.
antiphospholipid syndrome; systemic lupus erythematosus; thrombosis
HIV infection has been recognized as a prothrombotic condition and this association has now been proven by a large number of studies with a reported VTE frequency among HIV-infected patients ranging from 0.19% to 7,63 %/year. HIV infection is associated with a two to tenfold increased risk of venous thrombosis in comparison with a general population of the same age. Some risk factors demonstrated a strongest association with VTE such as, low CD4+ cell count especially in the presence of clinical AIDS, protein S deficiency, and protein C deficiency. Whereas other risk factors are still controversial like protease inhibitor therapy, presence of active opportunistic infections and presence of antiphospholipid antibodies, including anticardiolipin antibodies and lupus anticoagulant. Physicians caring for HIV positive patients should be able to recognize and treat not only the well-known opportunistic infections and malignancies associated with this chronic disease, but also be alert to the less well-known complications such as thromboses. Pulmonary embolism should be included in the differential diagnosis when patients with HIV/AIDS have unexplained dyspnea or hypoxemia. In younger individuals with VTE, especially men, without other identifiable risk factors for VTE, HIV should be considered. Because interactions between warfarin and antiretrovirals is possible, health care providers should also be alert to the potential of dangerously high or low INRs when they are giving anticoagulants to patients with HIV infection who are undergoing antiretroviral therapy.
Background: Antiphospholipid antibodies (aPLs) have been associated with thrombosis in the antiphospholipid antibody syndrome (APS) and with atherosclerotic vascular events in patients without APS. We examined the significance of aPLs in transient ischemic attack (TIA). Patients/methods: Patients with TIA <48 h from symptom onset were prospectively enrolled. Traditional aPLs, including anticardiolipin and β2-glycoprotein-I (β2GPI), and newer aPLs, including anti-phosphatidylserine/prothrombin (aPS/PT), β2GPI Domain 4/5 and β2GPI Domain 1 were measured. Primary outcome was a composite of stroke or death within 90 days or identification of a high risk stroke mechanism. Secondary outcomes were stroke or death and the presence of clinical/sub-clinical atherosclerosis. Results: Over 4.5 years, 167 patients were enrolled. Forty one patients (25%) had the composite endpoint. Antibodies were measured in 158 subjects. aPS/PT IgG antibodies were significantly associated with stroke/death (OR 16.3, 95% CI 2.3–116.7, p = 0.005) and were non-significantly associated with the composite endpoint (OR 4.7, 95% CI 0.8–29.2, p = 0.10). In multivariate analysis adjusting for ABCD2 risk score, aPS/PT IgG remained associated with stroke/death (OR 15.7, 95% CI 2.0–125.6, p = 0.009). Other aPLs were not associated with clinical outcome and no association between APLs and atherosclerosis was identified. Conclusion: In contrast to other aPLs, aPS/PT IgG antibodies are independently associated with stroke or death in patients with TIA.
anticardiolipin; antiphospholipid; biomarker; infarction; thrombosis; transient ischemic attack; aPS/PT antibodies