McMaster RARE-Bestpractices clinical practice guideline on diagnosis and management of the catastrophic antiphospholipid syndrome.

Background The McMaster RARE-Bestpractices project group selected the catastrophic antiphospholipid syndrome (CAPS) for a pilot exercise in guideline development for a rare disease. Objectives The objectives of this exercise were to provide a proof of principle that guidelines can be developed for rare diseases and assist in clinical decision making for CAPS. Patients/Methods The GIN-McMaster Guideline Development checklist and GRADE methodology were followed throughout the guideline process. The CAPS guideline was coordinated by a steering committee, and the guideline panel was formed with representation from all relevant stakeholder groups. Systematic reviews were performed for the key questions. To supplement the published evidence, we piloted novel methods, including use of an expert-based evidence elicitation process and ad hoc analysis of registry data. Results This paper describes the CAPS guideline recommendations, including evidence appraisal and discussion of special circumstances and implementation barriers identified by the panel. Many of these recommendations are conditional, because of subgroup considerations in this heterogeneous disease, as well as variability in patient values and preferences. Conclusions The CAPS clinical practice guideline initiative met the objective of the successful development of a clinical practice guideline in a rare disease using GRADE methodology. We expect that clinicians caring for patients with suspected CAPS will find the guideline useful in assisting with diagnosis and management of this rare disease.

McMaster RARE-Bestpractices clinical practice guideline on diagnosis and management of the catastrophic antiphospholipid syndrome

Background The McMaster RARE-Bestpractices project group selected the catastrophic antiphospholipid syndrome (CAPS) for a pilot exercise in guideline development for a rare disease. Objectives The objectives of this exercise were to provide a proof of principle that guidelines can be developed for rare diseases and assist in clinical decision making for CAPS. Patients/Methods The GIN-McMaster Guideline Development checklist and GRADE methodology were followed throughout the guideline process. The CAPS guideline was coordinated by a steering committee, and the guideline panel was formed with representation from all relevant stakeholder groups. Systematic reviews were performed for the key questions. To supplement the published evidence, we piloted novel methods, including use of an expert-based evidence elicitation process and ad hoc analysis of registry data. Results This paper describes the CAPS guideline recommendations, including evidence appraisal and discussion of special circumstances and implementation barriers identified by the panel. Many of these recommendations are conditional, because of subgroup considerations in this heterogeneous disease, as well as variability in patient values and preferences. Conclusions The CAPS clinical practice guideline initiative met the objective of the successful development of a clinical practice guideline in a rare disease using GRADE methodology. We expect that clinicians caring for patients with suspected CAPS will find the guideline useful in assisting with diagnosis and management of this rare disease.

Reduction of annexin A5 anticoagulant ratio identifies antiphospholipid antibody-positive patients with adverse clinical outcomes.

Essentials Annexin A5 resistance is a mechanism for antiphospholipid (aPL) syndrome. 750 patients with history of thrombosis, pregnancy complications and controls were tested. Reduced annexin A5 anticoagulant ratios (A5R) correlate with aPL antibody multipositivity. Reduced A5R may identify patients with a propensity for thrombosis or pregnancy complications. Click to hear an ISTH Academy presentation on antiphospholipid antibody syndrome by Drs de Laat and Bertolaccini SUMMARY: Background Annexin A5 (A5) is a potent anticoagulant protein that shields anionic phospholipids from coagulation reactions. Previous studies showed that antibodies from patients with antiphospholipid (aPL) syndrome (APS) interfere with annexin A5 crystallization and anticoagulant activity. Objective The purpose of this study was to investigate whether reduced values in the annexin A5 anticoagulant ratio (A5R) assay (i.e. 'annexin A5 resistance') are associated with adverse clinical events in aPL antibody-positive patients. Patients/Methods In an initial discovery phase, a group of 679 patient samples from a 'real-world' tertiary care hospital population were tested for A5R. This was followed by a validation-phase cohort of 71 asymptomatic patients with aPL antibodies and no prior history of an adverse clinical event whose baseline samples were tested for A5R then subsequently observed for up to 4 years. Results In the discovery-phase group, we found a reduction of A5R in aPL antibody-positive patients with thrombosis and/or pregnancy complications compared with aPL antibody-negative patients and controls. In addition, reduced A5R values in both the discovery-phase group and validation-phase cohort correlated with the extent of multi-positivity for standard APS tests, which has also been shown to be associated with a risk of adverse clinical outcomes. Conclusion Reduced A5R values were associated with a multi-positivity profile in aPL antibody-positive patients within both groups and with the development of adverse clinical events.

A new trick for an ancient drug: quinine dissociates antiphospholipid immune complexes.

Quinine, a quinoline derivative, is an ancient antipyretic drug with antimalarial properties that has been phased out by more effective synthetic candidates. In previous studies we discovered that hydroxychloroquine (HCQ), a synthetic antimalarial with structural similarities to quinine, reduced the binding of antiphospholipid (aPL) immune complexes to phospholipid bilayers. We performed ellipsometry and atomic force microscopy (AFM) studies to measure the effect of quinine on dissociation of anti-ß2-glycoprotein I (anti-ß2GPI) immune complexes. We found that quinine desorbed pre-formed ß2GPI-aPL immunoglobulin (Ig)G complexes from phospholipid bilayers at significantly lower molar concentrations than HCQ. Quinine also inhibited the formation of immune complexes with a higher efficacy than HCQ at equivalent drug concentrations of 0.2 mg/ml (0.192 ± 0.025 µg/cm(2) for quinine vs. 0.352 ± 0.014 µg/cm(2) for HCQ, p < 0.001). Furthermore, AFM imaging experiments revealed that addition of quinine disintegrated immune complexes bound to planar phospholipid layers. The desorptive and inhibitory effects of the old drug, quinine, toward ß2GPI-aPL IgG complexes and ß2GPI were significantly more pronounced compared to the synthetic antimalarial, HCQ. The results suggest that the quinoline core of the molecule is a critical domain for this activity and that side chains may further modulate this effect. The results also indicate that there may yet be room for considering new activities of very old drugs in devising clinical trials on potential non-anticoagulant treatments for antiphospholipid syndrome (APS).

Annexin A5 anticoagulant activity in children with systemic lupus erythematosus and the association with antibodies to domain I of ß2-glycoprotein I.

Children with systemic lupus erythematosus (SLE) have a high prevalence of antiphospholipid (aPL) antibodies and are at increased risk for aPL-related thrombosis. We investigated the association between annexin A5 anticoagulant activity and antibodies to the domain I portion of ß2-glycoprotein I (anti-DI antibodies), and propose a potential mechanism for the pathogenesis of aPL-related thrombosis. Using samples from 183 children with SLE collected during the Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) trial, we examined resistance to the anticoagulant effects of annexin A5, using the annexin A5 resistance (A5R) assay, and evaluated for anti-DI IgG antibodies. Children with SLE had higher frequency of anti-D1 antibodies (p = 0.014) and significantly reduced A5R compared to pediatric controls: mean A5R = 172 ± 30% versus 242 ± 32% (p < 0.0001). Children with SLE and positive anti-DI antibodies had significantly lower mean A5R levels compared to those with negative anti-DI antibodies: mean A5R = 155 ± 24% versus 177 ± 30% (p < 0.0001). In multivariate analysis, anti-DI antibodies (p = 0.013) and lupus anticoagulant (LA) (p = 0.036) were both independently associated with reduced A5R. Children with SLE have significantly reduced annexin A5 anticoagulant activity that is associated with the presence of LA and anti-DI antibodies.

'Non-criteria' aPL tests: report of a task force and preconference workshop at the 13th International Congress on Antiphospholipid Antibodies, Galveston, TX, USA, April 2010.

Abstract: Current classification criteria for definite APS recommend the use of one or more of three positive standardized laboratory assays, including anticardiolipin antibodies (aCL), lupus anticoagulant (LA), and antibodies directed to ß(2)glycoprotein I (anti-ß(2)GPI) to detect antiphospholipid antibodies (aPL) in the presence of at least one of the two major clinical manifestations (i.e., thrombosis or pregnancy morbidity) of the syndrome. Several other autoantibodies shown to be directed to phospholipids and/or their complexes with phospholipids and/or to proteins of the coagulation cascade, as well as a mechanistic test for resistance to annexin A5 anticoagulant activity, have been proposed to be relevant to APS. A task force of worldwide scientists in the field discussed and analyzed critical questions related to 'non-criteria' aPL tests in an evidence-based manner during the 13th International Congress on Antiphospholipid Antibodies (APLA 2010, 13-16 April 2010, Galveston, Texas, USA). This report summarizes the findings, conclusions, and recommendations of this task force.

The annexin A5-mediated pathogenic mechanism in the antiphospholipid syndrome: role in pregnancy losses and thrombosis.

Annexin A5 (AnxA5) binds to phospholipid bilayers, forming two-dimensional crystals that block the phospholipids from availability for coagulation enzyme reactions. Antiphospholipid (aPL) antibodies cause gaps in the ordered crystallization of AnxA5 which expose phospholipids and thereby accelerate blood coagulation reactions. The aPL antibody-mediated disruption of AnxA5 crystallization has been confirmed on artificial phospholipid bilayers and on cell membranes including endothelial cells, placental trophoblasts and platelets. Recently, we reported that hydroxychloroquine, a synthetic antimalarial drug, can reverse this antibody-mediated process through two mechanisms: (1) by inhibiting the formation of aPL IgG-beta2glycoprotein I complexes; and (2) by promoting the formation of a second layer of AnxA5 crystal 'patches' over areas where the immune complexes had disrupted AnxA5 crystallization. In another translational application, we have developed a mechanistic assay that reports resistance to AnxA5 anticoagulant activity in plasmas of patients with aPL antibodies. AnxA5 resistance may identify a subset of aPL syndrome patients for whom this is a mechanism for pregnancy losses and thrombosis. The elucidation of aPL-mediated mechanisms for thrombosis and pregnancy complications may open new paths towards addressing this disorder with targeted treatments and mechanistic assays.

Update of the guidelines for lupus anticoagulant detection. Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation Committee of the International Society on Thrombosis and Haemostasis.

One of the conclusions of the subcommittee meeting on Lupus Anticoagulant/Phospholipid dependent antibodies, held in Geneva on 2007, was the need to update the guidelines on Lupus Anticoagulant (LA) detection. Particular emphasis was given to several aspects discussed in this official communication. A new paragraph is dedicated to the patient selection, and aims to minimize inappropriate requests for LA testing. Modalities for blood collection and processing are fully delineated and the choice of tests is limited to dRVVT and a sensitive aPTT. Calculation of cut-off values for each diagnostic step are clearly stated. A final paragraph reports the interpretation of the results in general and in particular situations.

Resistance to annexin A5 anticoagulant activity: a thrombogenic mechanism for the antiphospholipid syndrome.

The phospholipid binding protein, annexin A5 (AnxA5), has potent anticoagulant properties that result from its forming 2-dimensional crystals over phospholipids, blocking the availability of the phospholipids for critical coagulation enzyme reactions. This article reviews the evidence that antiphospholipid antibodies can disrupt this anticoagulant shield and unmask thrombogenic anionic phospholipids, which may thereby contribute to thrombosis in patients with the antiphospholipid syndrome (APS). This mechanism for thrombosis in APS can be monitored with coagulation assays for resistance to anticoagulant activity of AnxA5.

Acquired von Willebrand syndrome 2004: International Registry--diagnosis and management from online to bedside.

The acquired von Willebrand syndrome (AVWS) is a rare bleeding disorder with laboratory findings similar to those for congenital von Willebrand disease. Unlike the congenital form, AVWS usually occurs in individuals with no personal or family history of bleeding. Large studies on AVWS are not available, diagnosis remains difficult and treatment empirical. Acquired von Willebrand syndrome is especially frequent in lympho- or myeloproliferative disorders. It is associated with solid tumours, immunological and cardiovascular disorders as well as other miscellaneous conditions. Diagnosis of AVWS is based on assays measuring ristocetin cofactor activity or collagen binding, which are usually abnormally low, while factor VIII coagulant activity is some-times within the reference range. FVIII/VWF inhibiting activities are found in only a minority of cases. Bleeding episodes in patients with AVWS are mostly of the mucocutaneous type and can be managed with desmopressin, plasma-derived factor VIII/von Willebrand factor (FVIII/VWF) concentrates and intravenous immunoglobulin. Recombinant activated factor VII can be useful in cases unresponsive to standard therapy. In conclusion, the AVWS, although rare, is certainly underestimated in clinical practice: The actual clinical impact of AVWS should be evaluated by prospective studies. The authors are co-ordinating an updated version of the International Registry on AVWS that will allow data to be entered directly online.

Non-stroke neurological syndromes associated with antiphospholipid antibodies: evaluation of clinical and experimental studies.

Although many types of neurological disorders and events have been described in association with antiphospholipid antibodies (aPL) and the antiphospholipid syndrome (APS), only ischaemic stroke is reasonably well established and accepted as a diagnostic criterion for the syndrome. We propose to evaluate, classify and rank the association of other neurological manifestations as possible, probable, or definite according to the data available from clinical studies and animal models. By these criteria, none of the neurological disorders or events such as epilepsy, psychiatric disease, dementia, transverse myelitis, multiple sclerosis-like disease, chorea, migraine, Guillian-Barrè syndrome, and sensory-neural hearing loss, can be definitely associated with aPL or APS.

Thrombophilia: what's a practitioner to do?

Management of thrombophilia is an ever-changing field as new disorders are described and additional clinical experience accrues. This paper addresses three common management issues in the care of patients with thrombophilia. The first two topics are updates for common but perplexing hypercoagulable states and the last topic introduces a new option for optimal management of oral anticoagulant therapy. Dr. Jacob Rand updates and organizes the approach to patients with antiphospholipid syndrome. This syndrome is a common acquired thrombophilic state, but the diagnosis and treatment of patients remains a challenge. Dr. Rand outlines his diagnostic and treatment strategies based on the current understanding of this complicated syndrome. Dr. Barbara Konkle addresses the special concerns of managing women with thrombophilia. Hematologists are often asked to advise on the risks of hormonal therapy or pregnancy in a woman with a personal or family history of thrombosis or with an abnormal laboratory finding. Dr. Konkle reviews the available data on the risks of hormonal therapy and pregnancy in women with and without known underlying thrombophilic risk factors. In Section III, Dr. Gail Macik will discuss a new approach to warfarin management. Several instruments are now available for home prothrombin time (PT) monitoring. Self-testing and self management of warfarin are slowly emerging as reliable alternatives to traditional provider-based care and Dr. Macik reviews the instruments available and the results of studies that support this new management option.

Bleeding and thrombotic complications in critically ill patients with cancer.

Alterations in hemostasis are common in patients with cancer admitted to the ICU. Depending on the underlying disease and specific hemostatic abnormality, the patient with cancer may develop bleeding, thrombosis, or both, such as DIC. Bleeding complications usually result from abnormalities in platelets or deficiency of coagulation factors and require specific blood or coagulation factor replacement. Similarly, critically ill patients with cancer are predisposed to thrombotic complications such as DVT, PE, and central vein thrombosis, the last as a result of the widespread use of long-term indwelling catheter devices. Advances in diagnostic imaging and the availability of newer and more potent anticoagulant agents have facilitated the care of these patients greatly. Ultimately, it is hoped that a thorough understanding of the various disturbances in hemostasis, innovative treatment approaches, and implementation of preventive strategies in patients with cancer will lead to decreased morbidity and improved survival rates of critically ill patients with cancer in the ICU.

Seasonal distribution of antiphospholipid antibodies.

BACKGROUND AND PURPOSE: The purpose of this study was to determine if there was a seasonal variation in antiphospholipid antibody (aPL) titers and whether this variation differed between stroke cases and control subjects. METHODS: IgG and IgM anticardiolipin and antiphosphatidyl serine antibody titers were obtained on serum samples from 884 stroke patients and 1024 control subjects over a 7-year period. Temporal distributions by month of blood draw were evaluated. RESULTS: Marked seasonal differences in the proportion of positive titers were found for control subjects, but no seasonal variability among patients was noted. In control subjects, positive titers occurred less frequently in the summer months, mirroring the seasonal trends seen in respiratory track infections and rheumatic fever. CONCLUSIONS: Our data suggest some aPL antibodies arise from different origins in patients and control subjects. The seasonality observed in the apparently normal population may be related to antibodies of infectious origin and is consistent with the reported lack of association with thrombosis of infection-related antibodies.

The annexinopathies: a new category of diseases.

The annexins are a family of highly homologous phospholipid binding proteins, which share a four-domain structure, with one member of the family - annexin VI - having a duplication consisting of eight domains. Thus far, ten annexins have been described in mammals. Although the biological functions of the annexins have not been definitively established, two human diseases involving annexin abnormalities ('annexinopathies') have been identified as of the time of writing. Overexpression of annexin II occurs in the leukocytes of a subset of patients having a hemorrhagic form of acute promyelocytic leukemia. Underexpression of annexin V occurs on placental trophoblasts in the antiphospholipid syndrome and in preeclampsia. Also, an animal model has been described in which annexin VII is underexpressed and is associated with disease, but the relevance of this animal model to human disease is not yet understood. Future research is likely to elucidate additional 'annexinopathies'.

The pathogenic role of annexin-V in the antiphospholipid syndrome.

The antiphospholipid antibody syndrome is an autoimmune condition in which venous or arterial thrombosis and recurrent pregnancy losses occur in patients having serologic evidence of antibodies against anionic phospholipid-protein complexes. The pathophysiologic mechanisms of this syndrome have not yet been established. Annexin-V, an anionic phospholipid-binding protein with potent anticoagulant activity, is necessary for maintenance of placental integrity and may play a thromboregulatory role at the vascular-blood interface by forming two-dimensional crystals which shield anionic phospholipids from complexing with coagulation proteins from circulating blood. We propose that thrombosis and pregnancy loss in the antiphospholipid syndrome may be caused by disruption of this Annexin-V shield by antiphospholipid (and cofactor) antibodies, thereby increasing the net quantity of thrombogenic phospholipids exposed to the circulating blood. The data accumulated from tissue immunohistochemistry, trophoblast and endothelial cell culture studies, coagulation studies using noncellular phospholipids, and competition studies on artificial phospholipid bilayer are consistent with the hypothesis that interference with the binding of Annexin-V to anionic phospholipid surfaces is an important mechanism of thrombosis and pregnancy loss in the antiphospholipid syndrome.

Antiphospholipid antibody-mediated disruption of the annexin-V antithrombotic shield: a thrombogenic mechanism for the antiphospholipid syndrome.

The mechanism(s) for thrombosis and pregnancy losses in the anti-phospholipid antibody syndrome have not yet been established. Annexin-V is an anionic phospholipid-binding protein with potent anticoagulant activity. The protein has been shown to be necessary for the maintenance of placental integrity and may play a thromboregulatory role at the maternal-fetal interface. There, it assembles over the apical surfaces of the placental villi and shields the underlying anionic phospholipids from availability for complexation with coagulation proteins. We have proposed that thrombosis and pregnancy loss in the antiphospholipid syndrome may be due to the disruption of the annexin-V shield by antiphospholipid (and co-factor) antibodies. The data accumulated from tissue immunohistochemistry, trophoblast and endothelial cell culture studies, coagulation studies using non-cellular phospholipids, and competition studies on artificial phospholipid bilayer are consistent with this hypothesis.