Guidelines on the investigation and management of the antiphospholipid syndrome

Evaluation of new commercial enzyme-linked immunosorbent assay kits in the laboratory diagnosis of antiphospholipid syndrome in view of the revised classification criteria of the antiphospholipid syndrome

Amendments to the Sapporo criteria for the diagnosis of the antiphospholipid syndrome (APS) have recently be published and include testing for the presence of IgG and IgM beta2-glycoprotein I (beta(2)GPI) antibodies. The Asserachrom Antiphospholipid antibodies line (Diagnostica Stago) with a monoclonal based standardisation, was evaluated in a Lupus anticoagulant (LAC) positive (n = 138) and a LAC negative (n = 134) populations. The ELISA line consists of the Asserachrom APA Screen, the Asserachrom APA IgG,M and the Asserachrom anti-beta(2)GPI IgG and IgM. Anti-prothrombin antibodies (APT), not being included in the updated laboratory criteria, have been tested by the Asserachrom anti-prothrombin IgG,M. Imprecision characteristics showed coefficients of variation (CV) ranging from 4.9% to 13.9%. Cut-off values were calculated with the 99 percentile. The Asserachrom APA Screen showed 1,5% false positive and 0,7% false negative results in correlation with the Asserachrom APA IgG,M. 14.7% of the patients were positive for beta2GPI antibodies, 30,0% of them showed a negative Asserachrom APA Screen. beta(2)GPI antibodies may be the only test positive in a minority of patients, so the Asserachrom APA Screen and the Asserachrom anti-beta(2)GPI IgG and IgM should be performed in parallel when APS is suspected. LAC and APA assays, however, remain essential in the laboratory diagnosis of APS.

Internal jugular vein thrombosis associated with acute mastoiditis in a pediatric age

OBJECTIVE

To discuss the clinical aspects and management of internal jugular vein thrombosis associated with acute otitis media.

STUDY DESIGN

Case reports and review of the literature.

SETTING

University hospital, tertiary referral center.

PATIENT

The authors describe two cases of internal jugular vein thrombosis, without sigmoid sinus thrombosis, secondary to acute otomastoiditis.

INTERVENTION

Jugular vein thrombosis was diagnosed in both cases by observation of filling defects of the involved jugular bulb on contrast-enhanced computed tomography and confirmed by conventional magnetic resonance and magnetic resonance venography.

RESULTS

Both patients recovered after recanalization of the vessel concomitant to anticoagulation and antibiotic treatment associated with a simple mastoidectomy.

CONCLUSION

Internal jugular vein thrombosis may be a complication of acute otitis media, without involvement of the sigmoid sinus and with a starting point in the jugular bulb. Anticoagulation associated with antibiotic therapy can be considered a safe and effective treatment. Surgery should only be performed to eliminate the source of infection from the middle ear and mastoid.

Antiphospholipid syndrome: a series of surgical emergencies and the current evidence for its management

It is generally accepted that antiphospholipid syndrome remains a major medical problem characterised by hypercoagulability, arterial and venous thrombosis and thrombocytopenia. It is unclear how best to treat these patients should they require emergency surgery. If a lupus anticoagulant is present, hypercoagulability may occur de novo but surgical interventions along with sepsis are two important predisposing factors. We describe three patients with primary antiphospholipid syndrome and discuss the implications for surgery.

Antiphospholipid Antibody Testing: Which Are Most Useful for Diagnosis?

Laboratory diagnosis of APS relies on the demonstration of a positive test for aPL. In clinical practice, the gold standard tests are those that detect beta2GPI-dependent aCL or LA. The question on the use of anti-beta2GPI asa routine diagnostic test remains unanswered, and testing for these antibodies should be only performed in very selected cases and not as an alternative to aCL or LA testing. Clinical utility and standardization are still lacking for other aPL specificities; therefore, their application as routine diagnostic tools is not recommended.

Antiphospholipid syndrome: An evolving story

Antiphospholipid Syndrome (APS) is a form of immune mediated thrombophilia, presenting as recurrent thrombotic events and pregnancy morbidity, in association with positive laboratory tests for antiphospholipid antibodies (APA) in the form of Lupus Anticoagulant (LA) or anticardiolipin antibodies(ACA). Insights into the pathophysiology of the condition suggest that some antibodies are prothrombotic in vivo, and that the mechanism of thrombosis is likely to be multifactorial. APS has a broad spectrum of clinical presentations, and the laboratory diagnosis can be difficult due to heterogeneity of APAs and poor standardisation of laboratory tests. Anticoagulation is the mainstay of the management of the thrombotic and obstetric complications of APS. The risk of recurrent thrombosis appears to be high, and the duration and intensity of therapy remains controversial. Randomised controlled trials have shown that standard intensity anticoagulation is adequate in most cases of venous thrombosis. Further trials are required to establish whether high intensity coagulation is of benefit in recurrent or arterial thrombosis. The optimal management of recurrent fetal loss is debated and large studies are required to establish a clear benefit of heparin and aspirin over aspirin alone or supportive care.

Antibodies against beta2-glycoprotein I complexed with an oxidised lipoprotein relate to intima thickening of carotid arteries in primary antiphospholipid syndrome

To explore whether antibodies against β₂-glycoprotein I (β₂GPI) complexed to 7-ketocholesteryl-9-carboxynonanoate (oxLig-1) and to oxidised low-density lipoproteins (oxLDL) relate to paraoxonase activity (PONa) and/or intima media thickness (IMT) of carotid arteries in primary antiphospholipid syndrome (PAPS). As many as 29 thrombotic patients with PAPS, 10 subjects with idiopathic antiphospholipid antibodies (aPL) without thrombosis, 17 thrombotic patients with inherited thrombophilia and 23 healthy controls were investigated. The following were measured in all participants: β₂GPI−oxLDL complexes, IgG anti-β₂GPI−oxLig-1, IgG anti-β₂GPI−oxLDL antibodies (ELISA), PONa, (para-nitrophenol method), IMT of common carotid (CC) artery, carotid bifurcation (B), internal carotid (IC) by high resolution sonography. β₂GPI−oxLDL complex was highest in the control group (p < 0.01), whereas, IgG anti-β₂GPI−oxLig1 and IgG anti-β₂GPI−oxLDL were highest in PAPS (p < 0.0001). In healthy controls, β₂GPI−oxLDL complexes positively correlated to IMT of the IC (p = 0.007) and negatively to PONa after correction for age (p < 0.03). PONa inversely correlated with age (p = 0.008). In PAPS, IgG anti-2GPI−oxLig-1 independently predicted PONa (p = 0.02) and IMT of B (p = 0.003), CC, (p = 0.03) and of IC (p = 0.04). In PAPS, PONa inversely correlated to the IMT of B, CC and IC (p = 0.01, 0.02 and 0.003, respectively). IgG anti-2GPI−oxLig-1 may be involved in PAPS related atherogenesis via decreased PON activity.

From normal to pathological hemostasis

PURPOSE

To review the evolution of knowledge on physiological hemostasis and the main abnormalities that may interfere with hemostasis in the perioperative period.

METHODS

Narrative review of the literature, including relevant papers published in English.

PRINCIPAL FINDINGS

Physiological hemostasis controls blood fluidity and rapidly induces hemostatic plug formation in order to stop or limit bleeding. The three distinct phases of the hemostatic process, primary hemostasis, coagulation and fibrinolysis are closely linked to each other and precisely regulated in order to efficiently close vessel wounds, promote vascular healing and maintain vessel patency. Primary hemostasis is the result of complex interactions between the vascular wall, platelets and adhesive proteins. Initiation of the coagulation pathway in vivo is secondary to the exposure of tissue factor (TF) and the formation of TF/VIIa complex which can activate both FIX and FX. This initiation phase is followed by a propagation phase with amplification of thrombin generation. Several control mechanisms exist for localizing fibrin formation to the site of injury including tissue factor pathway inhibitor, protein C system, antithrombin, and glycosaminoglycans on the vessel wall. Fibrinolysis is also a highly regulated system that controls fibrin dissolution. Both constitutive and acquired hemostasic defects exist. The consequences of these abnormalities are highly variable according to the type of defect, and to the genetic and environmental background.

CONCLUSION

Hemostasis is one of the most complex physiological self-defence systems, not only involved in control of blood fluidity but also interfering in major physiopathological processes. The evolution of our knowledge of the physiology of hemostasis has numerous implications for therapy.

Hypercoagulability: interaction between inflammation and coagulation in familial Mediterranean fever

Familial Mediterranean fever (FMF) patients in clinical remission are reported to have increased baseline inflammation. Normal function of the natural anticoagulant pathways is particularly needed in diminishing inflammatory responses. In the presence of subclinical inflammation, natural anticoagulant response may be exaggerated. We aimed to observe the anticoagulant-procoagulant status in attack-free FMF patients. Twenty-seven FMF patients diagnosed in accordance with Tel-Hashomer criteria, and 26 healthy controls were included. All patients were attack-free under regular colchicine treatment. Amyloidosis, autoimmunity, accompanying liver and renal disease, and vasculitis were excluded. Predisposing factors for thrombosis were not present. Acute phase reactants (APRs), anticardiolipin antibody positivity, prothrombin time (PT), activated prothrombin time, thrombin time (TT) and d-dimer, protein C activity, activated protein C resistance, free protein S, antithrombin, lupus anticoagulant, human prothrombin fragment F 1 + 2, and human thrombin/antithrombin III complex were analyzed for all subjects. APRs were comparable with controls. Autoimmune markers were negative in all. Anti-streptolysin titers were significantly different than the control group. PT, TT, protein C activity, and F 1 + 2 levels were significantly different from those of healthy controls. Shortened PT and TT, decreased protein C activity vs increased levels of F 1 + 2 suggested a hypercoagulable state in our patients. The hypercoagulable state detected in FMF patients suggests that screening with abnormal coagulation tests may be beneficial for tracing the future consequences of subclinical inflammation in these patients. Studies covering larger groups of patients are needed to verify the currently observed hypercoagulable status in FMF.

Can haematological tests predict cardiovascular risk? The 2005 Kettle Lecture*

The risk of venous or arterial thrombosis is routinely assessed by clinical variables (risk factors) supplemented by measurement of blood lipids and glucose for arterial thrombotic events. Haematological tests that might play a role in risk prediction include haemostatic variables, haematocrit and inflammatory markers (erythrocyte sedimentation rate, plasma viscosity, white cell count). Recent epidemiological studies of these phenotypes and related genotypes are reviewed. For the risk prediction of first venous thrombosis, screening for thrombophilias in 'high-risk' situations does not appear clinically effective or cost-effective; with the possible exception of women considering oral hormone replacement therapy. General screening after a first venous event to predict recurrence (or risk in asymptomatic relatives) does not appear effective; with the possible exception of d-dimer, which requires further study. For risk prediction of first arterial thrombosis, screening adds little to prediction by current clinical risk scores. Screening of persons after a first arterial event, or with atrial fibrillation (e.g. with D-dimer for stroke prediction), requires further study. In conclusion, haematological tests have very limited roles in the prediction of cardiovascular risk, and should only be used according to evidence-based guidelines. The need for management studies is highlighted.

The laboratory diagnosis of lupus anticoagulant in patients on oral anticoagulation

Laboratory-specific cut-off lupus ratios (LR), above which a plasma is judged positive for lupus anticoagulant (LA), were established for both activated partial thromboplastin time-based and dilute Russell viper venom time-based methods. The validity of using these cut-off values to determine the presence of LA in patients on oral anticoagulation (OAC) was assessed. A cohort of 40 patients (23 male and 17 female), aged 22-84 years (mean 52 years) were tested for LA at the time of a thrombotic event. Repeated testing was performed after the same patients were treated with OAC (international normalized ratio 2.0-3.5). For 36 patients (90%), LA status was unchanged pre- and on-OAC. Thirteen of the 40 patients (32.5%) were positive for LA both pre- and on-OAC. Of the 27 patients negative for LA pre-OAC, 23 remained negative on-OAC. The four discordant results were interesting in that LA positivity was demonstrated only after the patient was stable on-OAC. In our cohort of 40 patients, there was a trend for LRs to decrease on-OAC, but this did not reach statistical significance. The subset (4) went against this trend and became positive after the thrombotic event.

C-reactive protein level as a predictor of transient vs. sustained anticardiolipin antibody positivity

The antiphospholipid (APLA) syndrome is defined as the occurrence of venous or arterial thromboembolism or recurrent fetal loss in patients with a positive anticardiolipin (aCL) or lupus anticoagulant test on two occasions, 3 months apart. In this study, we sought to determine whether the level of C-reactive protein (CRP), a non-specific inflammatory marker, at the time of the initial positive aCL test is a predictor of the transient vs. sustained nature of the aCL. Patients with a positive aCL antibody test underwent high sensitivity (hs) CRP testing. A repeat aCL antibody assay was performed on a serum sample obtained 3-4 months later. The positive and negative predictive values of the hs-CRP assay as a predictor of the second aCL result were calculated and correlation between the hs-CRP result and second aCL result was determined. Fifty-four consecutive patients with a positive aCL test were studied. Forty-two had a positive aCL-2. The predictive value of a negative CRP test for a positive aCL-2 was found to be 82.5% (33 of 42 patients). A positive CRP was able to predict a negative aCL-2 in 35.7% of cases (nine of 14 patients). Our results suggest that the hs-CRP test may be useful in the assessment of patients with a positive aCL antibody test. A concurrently performed negative hs-CRP test result may be useful in making diagnostic and therapeutic decisions.

An audit of thrombophilia screens: results from the National Pathology Alliance benchmarking review

AIMS

The National Pathology Alliance benchmarking review has completed six years of data collection and analysis of the workload and organisation of haematology laboratories in the UK. This study audits national practice of routine thrombophilia screening against the current standards, as set out in the British committee for standards in haematology (BCSH) guidelines on investigation of heritable thrombophilia.

METHODS

Each laboratory completed a standard data collection questionnaire about the number of routine thrombophilia assays performed each year. Information was collected on which thrombophilia tests were performed as part of a routine thrombophilia screen. These results were then compared against the BCSH guidelines on investigation of heritable thrombophilia.

RESULTS

Of the 57 National Health Service trusts that submitted data for review in 2002/2003, 47 performed a routine thrombophilia screen. Ten laboratories complied with the guidelines but 37 laboratories did not.

CONCLUSION

There was variation in practice in the tests used in routine thrombophilia screens. There is evidence that some laboratories deviate from what may be regarded as "evidence based practice". The lack of compliance with the guidelines was in general associated with the performance of additional tests not recommended in the guideline. In a minority of laboratories, a clinically significant diagnosis would be missed by the failure to include one or more tests in a thrombophilia screen.

International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS)

New clinical, laboratory and experimental insights, since the 1999 publication of the Sapporo preliminary classification criteria for antiphospholipid syndrome (APS), had been addressed at a workshop in Sydney, Australia, before the Eleventh International Congress on antiphospholipid antibodies. In this document, we appraise the existing evidence on clinical and laboratory features of APS addressed during the forum. Based on this, we propose amendments to the Sapporo criteria. We also provide definitions on features of APS that were not included in the updated criteria.

The dilution effect of equal volume mixing studies compromises confirmation of inhibition by lupus anticoagulants even when mixture specific reference ranges are applied

INTRODUCTION

One of the recommended criteria for the laboratory diagnosis of lupus anticoagulants (LA) is demonstration of inhibitory activity. This is confirmed by performing mixing tests with normal plasma, usually in a 1:1 ratio, and demonstrating persistence of an abnormal clotting time in the screening test with significant confirmatory test reduction. However, the mixing with normal plasma can dilute the antibodies to undetectable levels and generate apparent negative results. No guidelines or consensus exist in how to interpret mixing study results.

PATIENTS AND METHODS

The present study assessed the 1:1 mixing study results from 600 patients with a thrombotic history positive for LA demonstrated in neat plasma by individual assays, or combinations, of dilute Russell's viper venom time, dilute activated partial thromboplastin time, activated seven lupus anticoagulant assay and Taipan snake venom time, plus confirmatory tests. Mixing tests were assessed initially using locally derived neat plasma reference ranges and subsequently with mixture specific ranges.

RESULTS

The mixture specific ranges had lower upper limits. Of the total LA positive results, 32.5% were positive in the mixing studies when neat plasma reference ranges were applied, and a further 11.2% demonstrated LA activity when using the mixture specific ranges. The remaining 56.3% had been diluted such that they did not elevate the screening test above the upper limit of normal or generated minimal prolongation with an insignificant difference between the screen and confirmatory test result sufficient to confirm LA activity.

CONCLUSIONS

The significant impact of the dilution effect in 1:1 mixing studies emphasises the limitations of mixing studies as a vehicle for confirmation of inhibition by LA antibodies.

Preliminary prospective study of the endocrinology of conception cycles and early pregnancy in women with antiphospholipid syndrome treated with low molecular weight heparin

OBJECTIVE

To examine whether there were any differences in the endocrinological profiles during conception cycle and early pregnancy between a control group and women with a history of recurrent miscarriage that was caused by antiphospholipid syndrome and that was treated with aspirin and low molecular weight heparin.

DESIGN

Prospective observational study.

SETTING

Recurrent Miscarriage Clinic, Department of Obstetrics and Gynaecology in a tertiary care centre.

PATIENT(S)

Five women with recurrent pregnancy loss were recruited as cases, whereas another five women having natural cycle donor insemination were used as control.

INTERVENTION(S)

Serial measurement of serum beta-hCG, activin A, and inhibin A was performed from postovulatory day 12 until 11 weeks of gestation.

MAIN OUTCOME MEASURE(S)

Comparison of levels of beta-hCG, activin A, and inhibin A at the time of conception onwards till 11 weeks in the two groups.

RESULT(S)

There were no significant differences between the two groups.

CONCLUSION(S)

There does not appear to be any obvious endocrinological alteration in the conception cycle of women with antiphospholipid syndrome compared with a control group. Furthermore, the initiation of heparin does not produce a significant change in activin A and inhibin A levels.

Thrombophilia in children with venous thromboembolic disease

Venous thromboembolic events (VTEs) in children are usually associated with underlying clinical conditions such as central venous line, cancer and cardiac diseases. The objective of this review is to present the importance of thrombophilia to the occurrence of childhood VTE. The reported prevalence of thrombophilia in children with VTE varies extremely between 10% and 78% in different registries. The variation in the reported prevalence most probably reflects differences in the clinical characteristics of the children studied and differences in study designs. The initial management of children with thrombophilia and VTE is similar to those individuals who do not have a specific inherited thrombophilic risk factor, except in the rare events of homozygous deficiencies of prothrombotic coagulation proteins. The impact of thrombophilic markers on long-term therapy and outcome of children with VTE has not been completely clarified. According to the current guidelines for thrombophilia, all children with VTE should be tested for a full panel of genetic and acquired prothrombotic traits. However, re-evaluation of co-morbid risk factors other than thrombophilic markers and careful consideration of the prognostic value of thrombophilic markers might help to change future attitude from the rigidity of current guidelines to more rational schemes.

The antiphospholipid syndrome

Antiphospholipid syndrome is an autoimmune disorder characterized by the association between antiphospholipid antibodies and venous or arterial thrombosis or obstetric complications. In spite of the recent progresses, many aspects of this disease remain unclear. In this review, we briefly focus on the most important advances in the pathophysiology, diagnosis and treatment of this condition.

Diagnosis of antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by recurrent vascular thrombosis and pregnancy losses. Laboratory diagnosis of APS relies on the demonstration of a positive anticardiolipin antibody test by an in-house or commercially available enzyme-linked immunosorbent assay, or on the presence of lupus anticoagulant by a coagulation-based test. Persistence of the positive results must be demonstrated, and other causes and underlying factors considered. Although it is universally recognized that the routine screening tests (anticardiolipin antibody or lupus anticoagulant) might miss some cases of APS, careful differential diagnosis and repeat testing are mandatory before the diagnosis of 'seronegative APS' can be made. Correct identification of patients with APS is important because prophylactic anticoagulant therapy can prevent thrombosis from recurring and treatment of affected women during pregnancy can improve fetal and maternal outcome.

Antiphospholipid antibodies in children with systemic lupus erythematosus: a prospective study in northern India

Twenty-seven children with systemic lupus erythematosus (SLE) were tested for antiphospholipid antibodies (APLA), i.e. lupus anticoagulant and immunoglobulin (Ig)G or IgM anticardiolipin antibodies (ACLA), with beta-2 glycoprotein I as cofactor, in a single-centre, prospective study over 2 years. Eighteen patients (67%) tested positively for one or the other APLA during the course of the study. Twelve children (44%) tested positively for IgG ACLA and ten (37%) for IgM ACLA, whereas eight (30%) were positive for lupus anticoagulant. In two patients with thrombosis, IgG anticardiolipin positivity was seen to be variable. Unlike the results of most other reports in the literature, lupus anticoagulant positivity was not consistently associated with thrombosis. A majority of the children (83%) tested positively for ACLA during disease activity. Immunoglobulin G and IgM ACLA positivity did not correlate significantly with disease status. The results of this prospective study would indicate that, though frequently present, APLA may be unable to be predictive of disease behaviour in children with SLE.

Long-term follow-up in 128 patients with primary antiphospholipid syndrome: do they develop lupus?

We retrospectively studied a large cohort of patients with primary antiphospholipid syndrome (APS) from 4 different referral centers to analyze the clinical and serologic features and, specifically, to determine the number of patients going on to develop systemic lupus erythematosus (SLE) or other autoimmune disease after long-term follow-up. The study included 128 unselected patients with primary APS who fulfilled the Sapporo International Criteria from 4 different tertiary hospitals in the United Kingdom, Mexico, and Spain. The patients had attended the referral centers between January 1987 and July 2001. We reviewed clinical and serologic characteristics according to a pre-established protocol. We used univariate analysis with the chi-squared or Fisher exact test and logistic regression to analyze possible factors related to the coexistence of SLE and APS. Ninety-seven female and 31 male patients fulfilled the criteria, with a median age of 42 +/- 12 years (range, 16-79 yr), and with a mean follow-up of 9 +/- 3 years (range, 2-15 yr). The main manifestations included deep vein thrombosis in 62 patients (48%), arterial thrombosis in 63 (49%) patients, pregnancy loss in 177/320 (55%) cases, and pulmonary embolism in 37 (30%) patients. Other clinical manifestations were migraine in 51 (40%) patients, thrombocytopenia in 48 (38%), livedo reticularis in 47 (37%), and valvular disease in 27 (21%). Serologic findings were anticardiolipin antibodies (aCL) IgG positive in 110 (86%) patients, aCL IgM in 36 (39%), lupus anticoagulant in 71 (65%), antinuclear antibodies in 47 (37%), and positive Coombs test in 5 (4%) patients. During the follow-up and after a median disease duration of 8.2 years (range, 1-14 yr), 11 (8%) patients developed SLE, 6 (5%) developed lupus-like disease, and 1 (1%) developed myasthenia gravis. The remaining 110 patients (86%) continued to have primary APS. After the univariate analysis, a family history of lupus, the presence of Raynaud phenomenon, migraine, psychiatric features, multiple sclerosis-like features, hemolytic anemia, low C3 and C4, and Coombs positivity conferred a statistically significant risk for the subsequent development of SLE (p < 0.05). Only the presence of Coombs positivity had statistical significance (odds ratio, 66.4; 95% confidence interval, 1.6-2714; p = 0.027) after the logistic regression evaluation. The current study confirms that progression from primary APS to SLE or lupus-like disease is unusual, even after a long follow-up. Only 3 patients developed anti-dsDNA antibodies. The presence of a positive Coombs test might be a marker for the development of SLE in patients with primary APS.

Hypercoagulable states and stroke: a selective review

Blood disorders have been implicated in approximately 5% to 10% of ischemic stroke, with an increased frequency in younger patients. Most disorders are associated with an increased thrombotic tendency and, therefore, an increased risk of ischemic stroke. Less commonly, a bleeding diathesis may predispose a patient to intracranial hemorrhage. While many conditions predisposing to thrombosis have been associated with stroke, there are relatively few prospective, epidemiological studies addressing hypercoagulable states and arterial stroke compared with the number of studies on the genetic thrombophilias, which are predominantly associated with venous thrombosis. When ordering tests of coagulation in stroke patients, one should keep in mind whether the results will influence therapy and/or patient outcome. It is generally not advocated to screen all stroke patients for a "hypercoagulable workup". Typically, patients to be screened for coagulation defects will have a prior history of one or more unexplained thromboembolic events. The yield for diagnosing a hypercoagulable state is typically greatest for young stroke patients or those with a family history of thrombosis and who have no other explanations for their stroke (cryptogenic stroke). The yield in typically low in unselected ischemic stroke patients and older patients. Treatment of a first stroke with a documented hypercoagulable state is typically long-term or indefinite duration warfarin, although there is a paucity of clinical trial data supporting this clinical approach.

Antiphospholipid syndrome with catastrophic bleeding and recurrent ischemic strokes as initial presentation of systemic lupus erythematosus

Bleeding is a rare manifestation of lupus anticoagulant-antiphospholipid syndrome unless associated with coagulation factor deficiency, thrombocytopenia, or intrinsic vascular defect. The authors report the clinical and laboratory findings in a 16-year-old boy with potent lupus anticoagulant who initially presented with recurrent epistaxis, hematuria, and gastrointestinal bleeding. Lupus anticoagulant potently inhibited assay systems for coagulation factors, but levels of factors II, IX, and XI appeared to be decreased (2-5% of mean normal levels). Within 2 weeks after diagnosis, spontaneous subdural hematomas developed. During hemostatic therapy, including plasmapheresis and infusions of recombinant activated factor VII and activated prothrombin complex concentrate, an ischemic stroke developed. Subsequent multifocal recurrent ischemic strokes developed despite immunosuppression. This case shows that lupus anticoagulant or antiphospholipid antibodies can cause both hemorrhagic and thrombotic complications in the same patient and may, in some patients, have multiple target antigens (eg, coagulation factors II, IX, XI).

Venous thromboembolism: diagnosis and management of pulmonary embolism

Pulmonary embolism (PE) affects 0.5-1 per 1000 people in the general population each year, and is one of the most common preventable causes of death among hospitalised patients. The clinical diagnosis of PE is unreliable and must be confirmed objectively with ventilation perfusion scanning or computed tomography pulmonary angiography. The diagnosis of PE can be reliably excluded, without the need for diagnostic imaging, if the clinical pretest probability for PE is low and the D-dimer assay result is negative. The initial treatment of PE is low-molecular-weight heparin or unfractionated heparin for at least 5 days, followed by warfarin (target international normalised ratio [INR], 2.0-3.0) for at least 3-6 months. Patients with a high clinical pretest probability of PE should commence treatment immediately while awaiting the results of the diagnostic work-up. Thrombolysis is indicated for patients with objectively confirmed PE who are haemodynamically unstable. Percutaneous transcatheter or surgical embolectomy may be life-saving in patients ineligible for, or unresponsive to, thrombolytic therapy. Unresolved issues in the management of venous thromboembolism include the roles of thrombophilia testing, thrombolysis for the treatment of stable PE patients who present with right ventricular dysfunction, and new anticoagulants; and the duration of anticoagulation for first unprovoked venous thromboembolism.

Intracerebral hemorrhage in a patient with SLE and catastrophic antiphospholipid syndrome (CAPS): report of a case

A 31-year-old woman was admitted to the hospital for investigation of left lower limb thrombophlebitis. History, physical examination, and laboratory investigations led to the diagnosis of systemic lupus erythematosus (SLE), complicated by secondary antiphospholipid syndrome (APS). Treatment included steroids, azathioprine, aspirin, and low molecular weight heparin. Sixty-three days later, she was admitted to the hospital again because of high fever, macroscopic hematuria, and dyspnea. Laboratory testing showed anemia and impaired renal function. High-resolution chest computed tomography (CT) revealed bilateral multiple peribronchial infiltrates with hemorrhage. Magnetic resonance imaging (MRI) angiography of the kidneys revealed left renal vein thrombosis combined with ischemia of the left kidney. Cyclophosphamide and methylprednisolone pulse treatment as well as intravenous immunoglobulins were started immediately. Despite intensive immunosuppressive and supportive treatment, she suffered three relapses of alveolar hemorrhage and died on day 40, due to severe intracerebral bleeding. The final diagnosis was catastrophic APS with diffuse alveolar hemorrhage and kidney involvement. The unusual combination of recurrent alveolar hemorrhage and death from intracerebral hemorrhage rather than thrombosis in a CAPS patient is discussed.

Antiphospholipid antibodies and thrombosis: do test patterns identify the patients' risk?

We retrospectively analyzed the antiphospholipid profile of 103 lupus anticoagulant-positive patients to investigate whether laboratory patterns emerged for their association with arterial and venous thrombosis in the antiphospholipid syndrome. Anticardiolipin, anti-<beta>2-glycoprotein I and antiprothrombin antibodies were combined with coagulation tests in different patterns, which included from 2 to 5 laboratory variables. Overall, 22 out of 180 available associations reached significance: 14 with any type of thrombosis and eight with venous thrombosis. In all but two cases, anticardiolipin antibodies>40 units were present in the laboratory patterns that reached significance. Anti-<beta>2-glycoprotein I antibodies were present in 11 significant patterns, and antiprothrombin antibodies in seven cases. Increasing the number of variables of the laboratory patterns did not increase the odds ratio (OR) towards thrombosis. In conclusion, this analysis confirmed that the presence of IgG anticardiolipin antibodies at medium to high titres, either alone or in various combinations with other tests, is clinically useful to establish the patients' risk of thrombosis. The role of the other antiphospholipid antibodies is less clear.

Cerebral thrombosis in childhood nephrosis

Sinovenous thrombosis is an uncommon but serious complication associated with nephrotic syndrome in children. We describe a 9-year-old Caucasian boy who presented with dehydration, vague neurological symptoms and seizures. A diagnosis of nephrotic syndrome was made during the course of hospitalization. The serum antithrombin III level was decreased and brain imaging showed cerebral sinovenous thrombosis. Anticoagulant therapy with heparin was commenced and the patient made a slow but gradual clinical, as well as radiological recovery. We describe this case and review available literature to highlight the importance of suspecting and recognizing this potentially life threatening complication and initiating early treatment.

Antiphospholipid syndrome: association between laboratory tests and clinical practice

Antiphospholipid antibodies are a wide and heterogeneous group of immunoglobulins, whose presence inpatients with arterial and venous thrombosis, and obstetrical complications defines the antiphospholipid syndrome. We systematically reviewed published articles on this syndrome to investigate the association between thrombosis and the most common antiphospholipid antibodies. Lupus anticoagulants were a clear risk factor for thrombosis, irrespective of the site and type of thrombosis, the presence of systemic lupus erythematosus, and the methods used to detect them. Anticardiolipin and anti 2-glycoprotein I antibodies were possible risk factors of thrombosis, at least in some selected situations. Conversely, the measurement of antiprothrombin antibodies was not helpful to define the patient's risk of thrombosis. These results are mainly due to the still far from optimal standardization of the methods to detect the various antiphospholipid antibodies.

Premature atherosclerosis in primary antiphospholipid syndrome: preliminary data

OBJECTIVE

To investigate the atherosclerosis hypothesis in primary antiphospholipid syndrome (PAPS).

METHODS

The intima media thickness (IMT) of carotid arteries and other cardiovascular risk factors was measured in 20 patients with PAPS (mean (SD) age 35 (12) years) and in 20 controls matched for age and sex (34 (12) years).

RESULTS

The frequency of smoking, hypertension, and dyslipidaemia was similar in the two groups, but plasma homocysteine was higher in patients with PAPS (mean (SD) 11.9 (6.2) v 8.2 (3.4) micromol/l, p = 0.037). The IMT was slightly greater in patients with PAPS than in controls at the carotid bifurcation (mean (SD) 0.61 (0.24) v 0.48 (0.09) mm, p = 0.04) and internal carotid artery (0.52 (0.22) v 0.40 (0.08), p = 0.01). These differences were more evident in patients aged >40 years than in those aged <30 years at the carotid bifurcation (0.76 (0.25) v 0.55 (0.06), p = 0.0007) and internal carotid artery (0.63 (0.25) v 0.45 (0.09), p = 0.02); no differences were seen in the younger age group compared with controls.

CONCLUSION

Atherosclerosis is a possibility in patients with PAPS in their fourth decade of life or older.

Thrombophilien bei Patienten mit isch�mischem Schlaganfall

Patients with ischemic stroke are sometimes found to have an underlying inherited (deficiency of protein C, protein S, antithrombin III, activated protein C resistance, prothrombin gene mutation, hyperhomocysteinemia) or acquired thrombophilia (lupus anticoagulant and anticardiolipin antibodies, hyperhomocysteinemia). Patient selection for thrombophilia screening is, therefore, a frequent question in managing patients with ischemic stroke. In this review we discuss patient selection and timing for laboratory tests for thrombophilia screening in stroke patients based on a literature review and we calculated overall costs per year in Germany for testing patients older than 18 years with an ischemic stroke of undetermined cause. As there is a lack of studies comparing anticoagulation with antiplatelet therapy in patients with diagnosed thrombophilia, laboratory screening for thrombophilia even in a selected group of patients with cryptogenic ischemic stroke remains of questionable value at present. An exception appears to be testing for lupus anticoagulant and anticardiolipin antibodies in younger patients with suspected antiphospholipid syndrome (two positive test results necessary), because anticoagulation seems to be superior to aspirin in patients with antiphospholipid syndrome.

Procedures for the outpatient management of patients with deep venous thrombosis1

Although deep venous thrombosis (DVT) is now widely managed on an outpatient basis, at a practical level there remains a potential for uncertainty as to which patient might prove suitable and in particular in regard to the lines of responsibility of each department involved in the delivery of clinical care. This guideline sets out recommendations for the standardization of the outpatient management of patients with DVT.

Thrombosis and the Antiphospholipid Syndrome

The antiphospholipid syndrome is an antibody-mediated hypercoagulable state characterized by recurrent venous and arterial thromboembolic events. Several studies have determined that the frequency of antiphospholipid syndrome in patients presenting with a venous thromboembolic event is between 4% and 14%. Because of the high risk for recurrent thromboembolism in these patients, current recommendations suggest a longer, potentially lifelong, course of antithrombotic therapy following an initial event. Although most authorities agree on an extended course of therapy, considerable controversy surrounds the optimal target therapeutic INR for patients with antiphospholipid syndrome. For an initial venous thromboembolic event, a target INR of 2.0 to 3.0 is supported by two prospective, randomized clinical trials. In contrast, relatively limited data exist for an initial arterial thromboembolic event in patients who have the antiphospholipid syndrome, and therapeutic recommendations range from aspirin to warfarin with a high target INR. Recurrent thromboembolic events can be extremely difficult to treat, and some patients may benefit from the addition of immunosuppressive therapies. Importantly, as many as 50% of the initial thromboembolic events sustained by patients with antiphospholipid antibodies occur in the setting of additional, coincident prothrombotic risk factors, indicating the importance of addressing any additional risk factors, such as hypercholesterolemia, in these patients. Prospective studies are needed to address the role of thromboprophylactic strategies in asymptomatic individuals with antiphospholipid antibodies in the absence of additional risk factors.

Effect of subcutaneous administration of dalteparin on lupus anticoagulant assays

INTRODUCTION

Treatment with unfractionated heparin (UH) is known to affect screening tests for lupus anticoagulant (LA). False positive test results are common because confirmatory steps lack sufficient specificity to distinguish between LA and the presence of heparin. In this study, we wanted to see if therapeutic levels of low-molecular weight heparin (LMWH) may cause false positive tests for LA or alter the LA test results in LA-positive patients. We also wanted to evaluate the need to include heparin-neutralizing agents in the reagents.

MATERIALS AND METHODS

Six healthy subjects without LA and six LA-positive patients were given 100 IU/kg dalteparin subcutaneously (s.c.). Samples for three in-house and two commercially available LA tests were taken before and 4 h after the injection. LA test results were calculated as normalized screening/confirm ratios or as recommended by the manufacturers.

RESULTS

With both healthy subjects and LA patients, only small and clinically unimportant differences in mean clotting times and final test results were seen 4 h after subcutaneous dalteparin injections, at anti-FXa activities within the therapeutic range.

CONCLUSIONS

Our study with dalteparin suggests that LMWH therapy with plasma concentrations within the therapeutic range does not cause false positive tests for LA when normalized screening/confirm ratios are applied; nor do test results for LA-positive patients seem to be significantly altered. Heparin-neutralizing agents did not influence test performance.

[Diagnosis of the antiphospholipid syndrome in anticoagulated patients]

The antiphospholipid syndrome is characterized by thromboembolic events and/or recurrent miscarriages in the presence of anticardiolipin antibodies and/or a lupus anticoagulant. Anticardiolipin antibodies are detected by ELISA whereas lupus anticoagulant detection includes a variety of coagulometric tests. However, a large number of patients with suspected antiphospholipid syndrome are anticoagulated with either heparin or coumadin when evaluated for the presence of a lupus anticoagulant and false positive test results may ensue, thus making coagulometric testing unreliable in this situation. Modifications of standard coagulometric tests have been suggested in order to circumvent this problem and studies of several patient cohorts have shown that the majority of patients with the antiphospholipid syndrome are anticardiolipin positive. However diagnosis in patients receiving anticoagulation remains a difficult task.

Alteration in the laboratory profile of a lupus anticoagulant in a patient with non-Hodgkin's lymphoma

We describe a patient with non-Hodgkin's lymphoma who developed a lupus anticoagulant (LA) detectable by activated partial thromboplastin time (APTT), dilute Russell's viper venom time (DRVVT) and kaolin clotting time (KCT). IgM anticardiolipin antibodies (ACA) were elevated. At a later admission, and following treatment for the lymphoma, routine coagulation screening showed an elevated prothrombin time (PT) without correction in mixing tests using a recombinant thromboplastin. Routine APTT was below the reference range and ACA levels were normal. Raw data for one-stage factor assays demonstrated the presence of an inhibitor. Analysis for LA was undertaken by DRVVT, KCT, activated seven lupus anticoagulant assay, Taipan snake venom time, platelet neutralisation procedures (PNP), Ecarin time and PT using rabbit brain thromboplastin. The results revealed a LA capable of prolonging the clotting times of the PNPs and PT using recombinant thromboplastin, but that was corrected using Ecarin venom, modified PNP and brain thromboplastin. The antibody also demonstrated the lupus anticoagulant co-factor effect. The factor VIII: C was markedly raised which may have masked the LA in the APTT. The changing laboratory profile over time demonstrates the effects of LA heterogeneity and variations in sensitivity and specificity of assays for the detection of antiphospholipid antibodies.

Lupus anticoagulant testing using plasma spiked with monoclonal antibodies: performance in the UK NEQAS proficiency testing programme

We report here results from a United Kingdom National Quality Assessment Scheme (UK NEQAS) exercise in which both plasma spiked with monoclonal antibodies and plasma from a patient known to have lupus anticoagulant (LA) were distributed to 245 hemostasis laboratories with a request for them to test for possible LA using their routine screening procedure. In general, good agreement was seen in the diagnosis of samples spiked with monoclonal antibodies against beta2-glycoprotein 1 (beta2GP1) and prothrombin, the LA-positive patient sample, and a normal pooled plasma; over 87% of centers correctly identified each sample. However, methods employing platelet neutralizing procedures were associated with a higher proportion of false-negative responses with the antiprothrombin-spiked sample, and it is important to recognize that sensitivity and responsiveness of different methods may vary between artificial plasmas and different LA-positive patient plasmas.

Adverse effects of lupus anticoagulant positive blood sera on placental viability can be prevented by heparin in vitro

OBJECTIVE

Lupus anticoagulant poses a significant risk factor for obstetric complications, whereas heparin improves live birth rates in those pregnancies. Pathophysiology of antiphospholipid antibodies on placental function involves coagulopathies and thrombosis but also dysregulated trophoblast turnover.

STUDY DESIGN

With the use of placental explant cultures, we assessed the effect of lupus anticoagulant positive sera (LA + sera) on apoptosis, mitosis, and invasion of trophoblast and determined the role of unfractionated heparin in regulating these functions.

RESULTS

LA + sera were associated with increased placental apoptosis (TUNEL, M30 formation, DNA laddering). LA + sera decreased villous trophoblast proliferation and reduced extravillous trophoblast invasion through matrigel. Heparin attenuated LA + sera-induced apoptosis and facilitated trophoblast invasion.

CONCLUSION

Lupus anticoagulant may impair placentation by increasing apoptosis, attenuating mitosis and reducing invasion of the trophoblast. The direct effects on trophoblast viability by heparin demonstrate an alternative biologic function for this anticoagulant and raise the possibility that anomalous trophoblast development may be therapeutically regulated.

The critical role of arginine residues in the binding of human monoclonal antibodies to cardiolipin

Previously we reported that the variable heavy chain region (V_H) of a human beta₂ glycoprotein I-dependent monoclonal antiphospholipid antibody (IS4) was dominant in conferring the ability to bind cardiolipin (CL). In contrast, the identity of the paired variable light chain region (V_L) determined the strength of CL binding. In the present study, we examine the importance of specific arginine residues in IS4V_H and paired V_L in CL binding. The distribution of arginine residues in complementarity determining regions (CDRs) of V_H and V_L sequences was altered by site-directed mutagenesis or by CDR exchange. Ten different 2a2 germline gene-derived V_L sequences were expressed with IS4V_H and the V_H of an anti-dsDNA antibody, B3. Six variants of IS4V_H, containing different patterns of arginine residues in CDR3, were paired with B3V_L and IS4V_L. The ability of the 32 expressed heavy chain/light chain combinations to bind CL was determined by ELISA. Of four arginine residues in IS4V_H CDR3 substituted to serines, two residues at positions 100 and 100 g had a major influence on the strength of CL binding while the two residues at positions 96 and 97 had no effect. In CDR exchange studies, V_L containing B3V_L CDR1 were associated with elevated CL binding, which was reduced significantly by substitution of a CDR1 arginine residue at position 27a with serine. In contrast, arginine residues in V_L CDR2 or V_L CDR3 did not enhance CL binding, and in one case may have contributed to inhibition of this binding. Subsets of arginine residues at specific locations in the CDRs of heavy chains and light chains of pathogenic antiphospholipid antibodies are important in determining their ability to bind CL.

A case of antiphospholipid syndrome presenting with pulmonary truncus and main pulmonary artery thrombosis

In patients with antiphospholipid syndrome (APS), thromboembolism and pulmonary hypertension are the most common pulmonary manifestations. Thrombotic obstruction at the level of the main and/or proximal pulmonary arteries is rare. We report a 40-year-old woman without any history of previous arterial and/or venous thrombosis who presented with severe dyspnea and was found to have pulmonary hypertension and positivity for anticardiolipin antibodies. Computed tomography revealed pulmonary truncus thrombosis extending to both right and left pulmonary arteries. The patient and her family refused surgical treatment. She had a prolonged hospital course, was unresponsive to thrombolytic, anticoagulant, antiplatelet, and immunosuppressive treatments, and died of right ventricle and respiratory failure 5 weeks later. This is the first reported case with thrombosis of pulmonary truncus and main pulmonary arteries concurrent with APS.

Type 1 and type 2 cytokine-producing CD4+ and CD8+ T cells in primary antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune condition characterized by thrombosis and/or recurrent fetal loss as well as the presence of autoantibodies against epitopes present on phospholipid-binding proteins. The role of cellular immunity in the pathogenesis of the syndrome remains unclear. We studied the cellular phenotype and the production of type 1 [interferon (IFN)-gamma, interleukin (IL)-2] and type 2 (IL-4, IL-10) cytokines by CD4+ and CD8+ T-lymphocyte subsets in 13 patients with untreated primary APS (PAPS) and in 32 healthy controls. The production of cytokines was determined in T cells after a 5-h culture with or without mitogenic stimulation using a flow cytometric method of intracellular cytokine staining. In six of the patients these studies were repeated 6 months later. In PAPS patients we found a reduced percentage of circulating CD4+CD45RA+ and an increased percentage and absolute number of CD8+HLA-DR+ cells. A type 1 response was observed in the patients' unstimulated cells, indicated by an increase in IFN-gamma-producing CD8+, IL-2-producing CD4+ T cells, and a decrease in IL-4-producing CD4+ and CD8+ T cells. Similar results were obtained in the patients at follow-up. Taken together, these results suggest a chronic in vivo stimulation of CD4+ and CD8+ T cells in PAPS patients exhibiting a type 1 polarization. Changes of cellular immunity may contribute to the pathogenesis of the clinical manifestations of the syndrome and might be proven to be useful targets for therapeutic interventions in the future.

Anti-cardiolipin antibody testing and reporting practices among laboratories participating in a large external Quality Assurance Program

AIMS

To investigate differences in anti-cardiolipin antibody (aCL) testing and reporting practices among diagnostic laboratories participating in the RCPA Quality Assurance Program (QAP) Immunology Program.

METHODS

A survey was sent to all 58 laboratories enrolled for aCL testing in the RCPA QAP Program requesting the following information: (1). manufacturer/type of assay; (2). isotype tested; (3). use of calibrators and controls; (4). whether calibrators, control and patient specimens were performed in singles or duplicates; (5). whether results were reported semi-quantitatively and/or numerically; (6). values used to define negative/positive and semi-quantitative cut-offs and how they were determined; and (7). whether interpretative comments were provided and their content.

RESULTS

Thirty-two surveys (55%) were received. Significant differences were present particularly in the following areas: (1). whether IgM isotype aCL testing was performed routinely or only on specific request; (2). whether controls/calibrators/specimens were tested in singles or duplicates; (3). whether results were reported numerically and/or semi-quantitatively; (4). the values used to define negative/positive and semi-quantitative range cut-offs; and (5). whether interpretative comments were provided and their content.

CONCLUSIONS

These differences in testing and reporting practices are likely to contribute to the variation in aCL results reported by different laboratories, particularly among those using the same assay.