Wide discrepancies in activated clotting times measured by two devices were detected for a patient with lupus anticoagulant in a cardiac surgery

INTRODUCTION:

For a patient with lupus anticoagulant (LA), activated coagulation time (ACT) was measured with two different types of devices (HEMOCHRON^® 801 and HEMOCHRON^® Jr).

CASE REPORT:

ACTs during heparinization measured with the HEMOCHRON^® 801 were over the range of measurement, while those with the HEMOCHRON^® Jr. reflected an almost normal response to heparin.

DISCUSSION:

The phospholipid contained in an activating agent of the HEMOCHRON^® Jr was suggested to have counteracted the effect of LA.

CONCLUSION:

It was indicated that the coagulation status for LA-positive patients might be better assessed by ACT measured with phospholipid in an activating agent, although careful interpretation is required.

Lupus Anticoagulant Positivity in Pediatric Patients With Prolonged Activated Partial Thromboplastin Time: A Single-Center Experience and Review of Literature

The presence of lupus anticoagulants (LAs) is an important cause of activated partial thromboplastin time (aPTT) prolongation found in children after an infection or during screening tests before surgical intervention. The authors retrospectively reviewed the charts of 68 patients who have been consulted from surgery departments with prolonged aPTT. These patients were reevaluated with aPTT analysis after 1 week. Thirteen patients had normal aPTTs. Therefore, 55 patients remained with prolonged aPTTs. LA positivity was detected in 39 patients. Sixteen of these had prolonged aPTT prior to surgery (41%). Others with LA positivity had systemic lupus erythematosus (SLE; n = 6), infection (n = 5), leukemia (n = 3), hemolytic uremic syndrome (n = 2), epistaxis (n = 2), antiphospholipid syndrome (APS; n = 1), chronic immune thrombocytopenic purpura (n = 1), acute poststreptococcal glomerulonephritis (n = 1), central nervous system (CNS) thrombosis (n = 1), and congenital heart disease (n = 1). None of the patients had bleeding history. LA positivity rarely leads to bleeding and/or thrombosis. Specific therapy is usually not needed. Further prospective multicenter studies are required to understand clinical outcomes and laboratory correlation in children with positive LA.

Antiphospholipid Antibodies and the Risk of Stroke in Urban and Rural Tanzania: A Community-Based Case-Control Study

BACKGROUND AND PURPOSE

The burden of stroke is high in sub-Saharan Africa, and improved knowledge of risk factors is needed. Antiphospholipid antibodies are a common acquired stroke risk factor in young individuals. Antiphospholipid antibodies may be induced by infectious diseases. Sub-Saharan Africa has a high infectious burden, and we analyzed the contribution of antiphospholipid antibodies to the risk of stroke in an incident population from rural and urban Tanzania.

METHODS

Stroke cases and age- and sex-matched community-acquired controls from the rural Hai district and urban Dar-es-Salaam areas of Tanzania were recruited in a wider study of stroke incidence between June 2003 and June 2006. Lupus anticoagulant, anticardiolipin, anti-β2-glycoprotein I, and antiphosphatidylserine/prothrombin antibodies were determined in stored plasma, as well as IgG antibodies against Treponema pallidum.

RESULTS

Data from 158 stroke cases and 369 controls were analyzed. Thirty cases (19%) and 4 controls (1%) had a lupus anticoagulant (odds ratio, 20.8; 95% confidence interval, 7.2-60.5). Anticardiolipin IgG was the only other antiphospholipid antibody subtype associated with increased stroke risk (odds ratio, 2.1; 95% confidence interval, 1.0-4.3), but this association disappeared when corrected for IgG antibodies against Treponema pallidum results. The prevalence of anti-β2-glycoprotein I IgG antibodies in the Tanzanian healthy population was high when Dutch cutoff values were applied (67%), whereas presence of anti-β2-glycoprotein I IgM was associated with a reduced stroke risk (odds ratio 0.3; 95% confidence interval, 0.1-1.1).

CONCLUSIONS

The presence of lupus anticoagulant is a strong, and to date unrecognized, risk factor for stroke in Tanzania, especially in young and middle-aged individuals.

Evaluation of phosphatidylserine-dependent antiprothrombin antibody testing for the diagnosis of antiphospholipid syndrome: results of an international multicentre study

Objective A task force of scientists at the International Congress on Antiphospholipid Antibodies recognized that phosphatidylserine-dependent antiprothrombin antibodies (aPS/PT) might contribute to a better identification of antiphospholipid syndrome (APS). Accordingly, initial and replication retrospective, cross-sectional multicentre studies were conducted to ascertain the value of aPS/PT for APS diagnosis. Methods In the initial study (eight centres, seven countries), clinical/laboratory data were retrospectively collected. Serum/plasma samples were tested for IgG aPS/PT at Inova Diagnostics (Inova) using two ELISA kits. A replication study (five centres, five countries) was carried out afterwards. Results In the initial study ( n = 247), a moderate agreement between the IgG aPS/PT Inova and MBL ELISA kits was observed ( k = 0.598). IgG aPS/PT were more prevalent in APS patients (51%) than in those without (9%), OR 10.8, 95% CI (4.0-29.3), p < 0.0001. Sensitivity, specificity, positive (LR+) and negative (LR-) likelihood ratio of IgG aPS/PT for APS diagnosis were 51%, 91%, 5.9 and 0.5, respectively. In the replication study ( n = 214), a moderate/substantial agreement between the IgG aPS/PT results obtained with both ELISA kits was observed ( k = 0.630). IgG aPS/PT were more prevalent in APS patients (47%) than in those without (12%), OR 6.4, 95% CI (2.6-16), p < 0.0001. Sensitivity, specificity, LR + and LR- for APS diagnosis were 47%, 88%, 3.9 and 0.6, respectively. Conclusions IgG aPS/PT detection is an easily performed laboratory parameter that might contribute to a better and more complete identification of patients with APS.

Antiphospholipid Antibodies: From General Concepts to Its Relation with Malignancies

Antiphospholipid syndrome (APS) is an adquired autoimmune pro-thrombotic disease characterized by arterial and/or venous thrombosis and/or fetal losses associated with the persistent presence of antiphospholipid antibodies (aPL) detectable by solid phase assays (anticardiolipin (aCL) and anti-β2 glycoprotein I, β2GPI) and/or functional coagulation test (lupus anticoagulant (LA)). Most patients with typical APS manifestations have the presence of one or more of conventional aPL, but, some patients might exhibit clinical features related with APS but with persistent negative determinations of "classic" aPL (seronegative APS). Expanding the network of autoantibodies in patients highly suspected of having APS but who have normal results from a conventional test using new antibodies (i.e., phosphatidylserine/prothrombin and β2GPI domain 1) would increase the diagnosis. Thrombosis is one of the leading causes of death among patients with cancer, representing up to 15% of all deaths. Cancer increases the risk of thrombosis and chemotherapy is further associated with a higher risk of thrombosis. In addition, aPL may contribute to an increased risk of thrombosis in patients with malignancies, although the levels do not seem to reflect their pathogenicity. Several malignancies, particularly hematological and lymphoproliferative malignancies, may indeed be associated with the generation of aPL but do not necessarily enhance the thrombophilic risk in these patients.

Persistent triple antiphospholipid antibody positivity as a strong risk factor of first thrombosis, in a long-term follow-up study of patients without history of thrombosis or obstetrical morbidity

Introduction The long-term risk of first thrombosis and benefit of prophylaxis in antiphospholipid antibody (aPL) carriers without history of thrombosis or obstetrical morbidity is poorly known. This study aimed to evaluate the long-term rate and risk factors associated with a first thrombosis in those patients. Patients and methods After a prior study ended in December 2005 and was already published, we extended the follow-up period of our cohort of aPL carriers. Results Ninety-eight of the 103 patients of the previous study were included. The annual first thrombosis rate was 2.3% per patient-year during a median of 13 years (6-17). None of the baseline characteristics was predictive of risk of first thrombosis, but persistent aPL over time were associated with an increased risk. The stronger association was found in triple aPL-positive carriers: OR 3.38 (95% CI: 1.24-9.22). Of note, conversely to our previous findings, no benefit of aspirin prophylaxis was observed. Conclusion The risk of first thrombosis in aPL carriers without history of thrombosis or obstetrical morbidity was significant, persisted linearly over time and was associated with persistent aPL. This risk was especially increased in triple aPL-positive carriers, in whom a close follow-up seems to be necessary. Nevertheless, the benefit of aspirin prophylaxis remained unclear.

Diagnostic difficulties of factor XI deficiencies: interferences' assay or real deficit?

Madam P, 77 years old, consulted in the hemostasis department after a coagulation anomaly was discovered during her preoperative test for a total hip prosthesis. After confirmation of a persistent and increased aPTT, additional tests were performed and showed the presence of antiphospholipid antibodies. Factor VIII level could be corrected after the plasma dilution to 1/40(th). But successive dilutions were not enough to obtain a correct factor IX (FIX) and factor XI (FXI) level. FIX level was obtained by chromogenic method in order to avoid the interferences caused by the antibodies. Finally, despite the change of reagents and dilutions up to 1/160(th), the FXI level couldn't be determined. Despite these results and those of the thrombin generation assay, the surgery was successfully done without specific treatment thanks to the absence of hemorrhagic history. This observation highlights the diagnostic and monitoring difficulties for uncommon clotting factor deficit. The development of interference free test could increase the support for these patients.

Pearls and pitfalls in factor inhibitor assays

The proper performance and interpretation of factor inhibitor assays is a critical role for the hemostasis laboratory. Both false-positive and false-negative inhibitor assays may be reported, leading to serious patient mismanagement. Knowledge and recognition of common causes of both false-positive and negative-results can aid in the identification of these potential pitfalls. Safeguards to reporting accurate factor inhibitor assays include initial characterization of the sample, using the Nijmegen modification, properly performing and interpreting an incubated mixing test in conjunction, and performing two dilutions for each dependent dilution in the factor inhibitor assay.

Antiphospholipid antibodies and the risk of severe and non-severe pre-eclampsia: the NOHA case-control study

BACKGROUND

pre-eclampsia (PEecl) can be defined as non-severe (NS-PEecl) or severe (S-PEecl). Our study aimed to determine the incidence of antiphospholipid antibodies (aPLs) in women with a past history of NS-PEecl or S-PEecl.

PATIENTS AND METHODS

This case-control study includes 195 control women, 199 NS-PEecl patients and 143 S-PEecl patients whose plasma samples were collected 6 months after their first delivery. Each plasma was tested for lupus anticoagulant (LA), anticardiolipin (aCL) and antiβ2GP1 antibodies, as well as antibodies against phosphatidylserine/prothrombin complex (aPS/PT) and domain I of the β2GP1.

RESULTS

When compared with the control group no significant associations were found for the NS-PEecl group after adjustment of confounding variables. For the S-PEecl group, there was an association with antiβ2GP1 immunoglobulin G (IgG) (OR 16.91, 95% CI 3.71-77.06), as well as age, obesity, smoking and multiparity. Antiβ2GP1-domain I IgG was associated with aCL, antiβ2GP1 and aPS/PT IgG in the three groups. aPS/PT IgG was associated with aCL IgG, and aPS/PT IgM was associated with aCL and antiβ2GP1 IgM in the three groups.

CONCLUSION

S-PEecl is a distinct entity from NS-PEecl and is mainly associated with the presence of antiβ2GP1 IgG. Antiβ2GP1 domain I correlates with other aPL IgG tests, and aPS/PT may be promising in patients for whom LA tests cannot be interpreted.

[Non-bacterial thrombotic endocarditis on the bicuspid aortic valve in a 25-year-old male with lupus anticoagulant]

Non-bacterial thrombotic endocarditis (NBTE) is characterized by presence of sterile vegetations that develop from fibrin and platelets on heart valves. The main conditions predisposing to NBTE are malignancy, autoimmune diseases and other hypercoagulable states. The authors describe a case of a 25-year-old male, in whom NBTE was diagnosed on the bicuspid aortic valve. The presence of significant aortic regurgitation and dental caries were initially suggestive of infective endocarditis; although, serial blood culture were negative and procalcytonin concentration was within normal ranges. Empiric antibiotic therapy did not result in diminishing of vegetations, similarly to the anticoagulation treatment initiated when strongly positive lupus anticoagulant was detected in laboratory findings. Aortic valve replacement was necessary. Bacteriologic examination of the excised valve was negative. Widespread fibrin masses at different stages of organization on the leaflets confirmed NBTE in histopathologic assessment. Lupus anticoagulant was probably secondary to thyroid autoimmune disease.

Ribophorin II is involved in the tissue factor expression mediated by phosphatidylserine-dependent antiprothrombin antibody on monocytes

OBJECTIVE

Phosphatidylserine-dependent, also called aPS-PT, recognizes the phosphatidylserine-prothrombin complex, which is associated with APS. We have previously reported that aPS-PT induces tissue factor (TF) expression on monocytes through the p38 mitogen-activated protein kinase pathway. However, the cell surface interaction between prothrombin and aPS-PT, which is involved in the activation of cell-signalling pathways, has remained unknown. The objective of this study was to identify membrane proteins involved in the binding of prothrombin and aPS-PT to monocyte surfaces as well as the induction of TF expression.

METHODS

RAW264.7 cells with FLAG-tagged prothrombin were incubated and separated using affinity chromatography with anti-FLAG antibody-conjugated Sepharose beads. Immunopurified proteins were then analysed by an online nano-liquid chromatography-tandem mass spectrometry. The binding between prothrombin and the identified protein, ribophorin II (RPN2), was analysed by ELISA and surface plasmon resonance. To elucidate the role of RPN2 in TF expression, the TF mRNA level in RAW264.7 cells treated with RPN2 small interfering RNA was determined by quantitative real-time PCR (qPCR).

RESULTS

RPN2 was identified as a candidate molecule involved in the binding of prothrombin to the cell surface. The binding between prothrombin and RPN2 was confirmed by ELISA and surface plasmon resonance. RAW264.7 cells treated with RPN2 small interfering RNA showed significant reduction of the TF expression mediated by prothrombin and a mouse monoclonal aPS-PT.

CONCLUSION

We identified that RPN2 is one of the prothrombin-binding proteins on monocyte surfaces, suggesting that RPN2 is involved in the pathophysiology of thrombosis in patients with APS.

Thrombophilia in 67 Patients With Thrombotic Events After Starting Testosterone Therapy

We compared thrombophilia in 67 cases (59 men and 8 women) with thrombotic events after starting testosterone therapy (TT) versus 111 patient controls having unprovoked venous thrombotic events without TT. In the 67 patients, thrombosis (47 deep venous thrombosis-pulmonary embolism, 16 osteonecrosis, and 4 ocular thrombosis) occurred 6 months (median) after starting TT. Cases differed from controls for factor V Leiden heterozygosity (16 of the 67 [24%] vs 13 [12%] of the 111, P = .038) and for lupus anticoagulant (9 [14%] of the 64 vs 4 [4%] of the 106, P = .019). After a first thrombotic event and continuing TT, 11 cases had a second thrombotic event, despite adequate anticoagulation, 6 of whom, still anticoagulated, had a third thrombosis. Screening for thrombophilia before starting TT should identify men and women at high risk for thrombotic events with an adverse risk-benefit ratio for TT. When TT is given to patients with familial and acquired thrombophilia, thrombosis may occur and recur in thrombophilic men despite anticoagulation.

Splenic Infarction in Acute Infectious Mononucleosis

BACKGROUND

The evaluation of a febrile patient with acute abdominal pain represents a frequent yet possibly challenging situation in the emergency department (ED). Splenic infarction is an uncommon complication of infectious mononucleosis, and may have a wide range of clinical presentations, from dramatic to more subtle. Its pathogenesis is still incompletely understood, yet it may be associated with the occurrence of transient prothrombotic factors.

CASE REPORT

We report the case of a 14-year-old boy who presented with fever, sore throat, left upper quadrant abdominal pain, and splenomegaly, with no history of recent trauma. Laboratory tests revealed a markedly prolonged activated partial thromboplastin time and positive lupus anticoagulant. Abdominal ultrasonography showed several hypoechoic areas in the spleen consistent with multiple infarctions. Magnetic resonance imaging eventually confirmed the diagnosis. He was admitted for observation and supportive treatment, and was discharged in good condition after 7 days. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Spontaneous splenic infarction should be considered in the differential list of patients presenting with left upper quadrant abdominal pain and features of infectious mononucleosis; the diagnosis, however, may not be straightforward, as clinical presentation may also be subtle, and abdominal ultrasonography, which is often used as a first-line imaging modality in pediatric EDs, has low sensitivity in this scenario and may easily miss it. Furthermore, although treatment is mainly supportive, close observation for possible complications is necessary.

The addition of idarucizumab to plasma samples containing dabigatran allows the use of routine coagulation assays for the diagnosis of hemostasis disorders

BACKGROUND

The anticoagulant effect of dabigatran can be approximated by its prolongation of routine coagulation assays. Consequently, dabigatran also interferes with thrombophilia screening or with diagnosing hemostasis disorders that have developed after the initiation of anticoagulant treatment, such as vitamin K deficiency or acquired hemophilia A.

OBJECTIVES

This study was carried out to determine whether idarucizumab, a humanized antibody fragment that binds dabigatran, could fully neutralize dabigatran in routine diagnostic coagulation assays conducted in vitro, thereby preventing false-positive or false-negative diagnostic readouts.

METHODS

Preliminary experiments identified coagulation assays that were sensitive to dabigatran, and identified a concentration of idarucizumab that neutralized the effects of dabigatran. These assays were then carried out with patient and control plasma samples spiked with dabigatran, with or without a molar excess of idarucizumab.

RESULTS

Dabigatran altered the prothrombin time, activated partial thromboplastin time and thrombin time, and the measurement of intrinsic and extrinsic factor levels. Screening and confirmation tests used for lupus anticoagulant detection were prolonged by dabigatran, falsely suggesting the presence of lupus anticoagulant. Conversely, the addition of dabigatran falsely corrected an abnormal activated protein C resistance ratio. Addition of idarucizumab completely normalized these measurements, and allowed the correct identification of normal and abnormal samples with these assays.

CONCLUSIONS

In vitro addition of idarucizumab to plasma samples containing dabigatran fully neutralizes the drug, and facilitates the use of routine coagulation assays to allow the diagnosis of hemostasis disorders that may be concurrently present in patients taking dabigatran.

Antiphospholipid antibodies and infertility

Since the late 1980s some publications have proposed that antiphospholipid antibodies (aPL) may have some relationship with infertility, considering reported deleterious effects that aPL exert on trophoblast proliferation and growth. Although not included in current classification criteria for antiphospholipid syndrome, many physicians investigate for aPL in patients with a history of infertility, including antibodies not listed in classification criteria, and most of those patients will receive anticoagulant therapy if any of those antibodies have a result considered positive. A review of literature was conducted searching for studies that investigated the association of aPL and infertility and if aPL positivity alters in vitro fertilization (IVF) outcome. The definition of infertility, routine work-up to exclude other causes of infertility, definition of IVF failure as inclusion criteria and control populations were heterogeneous among studies. Most of them enrolled women over 40 years of age, and exclusion of other confounding factors was also inconsistent. Of 29 studies that assessed aPL positivity rates in infertile women, the majority had small sample sizes, implying a lack of power, and 13 (44.8%) reported higher frequency of aPL in infertile patients compared to controls, but most of them investigated a panel of non-criteria aPL tests, whose clinical significance is highly controversial. Only two studies investigated all three criteria tests, and medium-high titer of anticardiolipin cut-off conforming to international guidelines was used in one study. Considering IVF outcome, there was also disparity in this definition: few studies assessed the live birth rate, others the implantation rate. Of 14 publications that addressed the relationship between aPL and IVF outcome, only two described a detrimental effect of these autoantibodies. In conclusion, available data do not support an association between aPL and infertility, and aPL positivity does not seem to influence IVF outcome. Well-designed clinical studies recruiting women with a clear diagnosis of infertility and a high-risk aPL profile should be performed to test whether clinically relevant aPL do-or not-exert an effect on human fertility.

Mixing studies in lupus anticoagulant testing are required at least in some type of samples

BACKGROUND

According to the ISTH guidelines for lupus anticoagulant (LAC) testing, the second step in the three-step procedure (screening, mixing, and confirmation) is the mixing test, which improves the discrimination between the presence of an inhibitor and coagulation factor deficiencies such as those occurring in patients receiving vitamin K antagonists (VKAs).

OBJECTIVES

From a retrospective analysis of dilute Russell viper venom (dRVVT) results, we evaluated the impact of the mixing test result on the interpretation of LAC positivity.

METHODS

We interpreted the dRVVT clotting times with and without taking into account the results of the mixing test in a patient population with prolonged screening test (n = 267) with special attention to the patients receiving VKAs.

RESULTS AND CONCLUSIONS

The number of samples classified as 'LAC positive' differed substantially depending on the method of interpretation; 170 and 235 of 267 samples were classified as LAC positive with the three- and two-step procedure, respectively. Discrepancy between the two-step (without mixing step) and the three-step procedure was due to not including a mixing test and was more pronounced in the VKA patient population. Screen/confirm ratios carried out on a 1:1 mix of patient and normal pooled plasma (NPP) gave a lower incidence of 59 of 267. We advise continuing to perform mixing test to avoid false-positives. In patients with discrepant results between the two- and three-step dRVVT interpretation, mainly observed in VKA-treated patients, we advise retesting of the patients preferable beyond the period of anticoagulant therapy and additional testing for anti-beta2GPI and/or anti-cardiolipin antibodies.

Interactions between rivaroxaban and antiphospholipid antibodies in thrombotic antiphospholipid syndrome

INTRODUCTION

Rivaroxaban can affect lupus anticoagulant (LA) testing and antiphospholipid antibodies (aPL) may interfere with the anticoagulant action of rivaroxaban.

AIMS

To establish the influence of rivaroxaban on LA detection and of aPL on the anticoagulant action of rivaroxaban.

METHODS

Rivaroxaban and 52 IgG preparations (20 LA+ve, 12 LA-ve thrombotic antiphospholipid syndrome [APS] patients, and 20 normal controls [NC]) were spiked into pooled normal plasma (PNP) for relevant studies. LA detection was also studied in APS patients receiving rivaroxaban 20 mg once daily.

RESULTS

In vitro spiking of samples with rivaroxaban showed no false positive LA with Textarin time, Taipan venom time/Ecarin clotting time (TVT/ECT), dilute prothrombin time (dPT) and in-house dilute Russell's viper venom time (DRVVT), but false positives in the majority of NC and LA negative IgG with two commercial DRVVT reagents at 250 ng/mL but not 50 ng/mL rivaroxaban. Ex vivo studies: six LA+ve patients on rivaroxaban remained LA positive with TVT/ECT and DRVVT at peak (162-278 ng/mL) and trough (30-85 ng/mL) rivaroxaban levels. Six LA-ve patients became (apparently) LA+ve with two DRVVT reagents (test/confirm ratio median [confidence interval], 1.6 [1.3-1.8], 1.6 [1.4-1.9]) but not with TVT/ECT at peak rivaroxaban levels, and remained LA-ve with both DRVVT reagents and TVT/ECT at trough levels. aPL positive IgG spiking of PNP had no effect on rivaroxaban's anticoagulant action on thrombin generation or rivaroxaban anti-Xa levels.

CONCLUSIONS

The TVT/ECT ratio and Textarin time were not affected even at peak rivaroxaban levels, enabling detection of LA ex vivo. aPL had no effects on rivaroxaban's anticoagulant action in vitro.

Lupus anticoagulant acquired hypoprothrombinemia syndrome in childhood: two distinct patterns and review of the literature

INTRODUCTION

Lupus anticoagulant associated with acquired prothrombin deficiency also known as 'lupus anticoagulant hypoprothrombinemia syndrome' (LAHS) is an entity that is well described in adults and is usually associated with autoimmune conditions (LAHS-AI). However, in children, LAHS has unique features that are distinct from the adult type.

AIMS

We report two paediatric cases of LAHS, describe their distinct patterns and review the paediatric literature on LAHS.

METHODS

Case studies on two patients with LAHS were reviewed, details on their presentation, work up and management were extracted. A Medline search was conducted on LAHS in children between 1960 and 2014; Articles in languages other than English were excluded.

RESULTS

The case studies highlight the differences in the two patterns of childhood LAHS. Additionally the review of the literature reveals that there are 15 case reports and 5 case series that report 25 children with LAHS-AI, 9 case reports and 6 case series report 26 children of LAHS associated with viral infections (LAHS-VI). At presentation, all patients with LAHS-AI had positive laboratory tests for autoimmune diseases, most commonly for systemic lupus erythematosus while these tests were negative in LAHS-VI. All patients with LAHS-AI had a protracted course and needed prolonged treatment with immune-suppressive therapy while patients with LAHS-VI resolved spontaneously or needed short-term immune-modulating therapy.

CONCLUSION

In childhood, two distinct patterns of LAHS are observed, either associated with infection or autoimmune disease. Initial diagnostic investigations are critical to differentiating these two patterns as the prognosis and outcome for each is distinct.

Right Atrial Thrombosis in Antiphospholipid Syndrome with Secondary Immune Thrombocytopenia

Background Antiphospholipid syndrome (APS) is an acquired thrombophilia that can be associated with decreased platelet counts.

Case A 67-year-old woman presented with thrombocytopenia and a symptomatic right atrial mass suspicious of cardiac myxoma. Prolongation of the activated partial thromboplastin time (aPTT) was caused by a strong lupus anticoagulant, and bone marrow cytology was consistent with accelerated platelet clearance. The patient underwent uneventful resection of the atrial tumor, which turned out to be a calcified fibrin-rich thrombus. Definitive APS was diagnosed and long-term anticoagulation recommended.

Conclusion When evaluating patients with right atrial masses, findings of thrombocytopenia and/or aPTT prolongation should raise the suspicion of APS-associated thrombosis.

Primary prophylaxis to prevent obstetric complications in asymptomatic women with antiphospholipid antibodies: a systematic review

OBJECTIVE

Obstetric complications are common in patients with antiphospholipid syndrome. However, the impact of antiphosholipid antibodies (aPL) in the pregnancy outcomes of asymptomatic aPL carriers is uncertain. The aim of this systematic review is to assess whether primary prophylaxis is beneficial to prevent obstetric complications during pregnancy in asymptomatic women positive for aPL who have no history of recurrent pregnancy loss or intrauterine fetal death.

METHODS

Studies evaluating the effect of prophylactic treatment versus no treatment in asymptomatic pregnant aPL carriers were identified in an electronic database search. Design, population and outcome homogeneity of studies was assessed and meta-analysis was performed. The pooled Mantel-Haenszel relative risk of specific pregnancy outcomes was obtained using random effects models. Heterogeneity was measured with the I(2) statistic. All analyses were conducted using Review Manager 5.3.

RESULTS

Data from five studies involving 154 pregnancies were included and three studies were meta-analysed. The risk ratio and 95% confidence interval (CI) of live birth rates, preterm birth, low birth weight and overall pregnancy complications in treated and untreated pregnancies were 1.14 (0.18-7.31); 1.71 (0.32-8.98); 0.98 (0.07-13.54) and 2.15 (0.63-7.33),respectively. Results from the meta-analysis revealed that prophylactic treatment with aspirin is not superior to placebo to prevent pregnancy complications in asymptomatic aPL carriers.

CONCLUSION

This systematic review did not find evidence of the superiority of prophylactic treatment with aspirin compared to placebo or usual care to prevent unfavourable obstetric outcomes in otherwise healthy women with aPL during the first pregnancy.

Real-world practice of obstetricians in respect of assays for antiphospholipid antibodies

OBJECTIVE

The international classification criteria (CC) for definite antiphospholipid syndrome (APS) recommend confirmation of the sustained presence, for at least 12 weeks, of both lupus anticoagulant (LA), as determined by aPTT and RVVT, and anti β2glycoprotein I (β2GPI) or anticardiolipin (aCL) IgG and/or IgM. However, it remains unclear whether obstetricians comply with the aforementioned CC for the diagnosis of APS in daily clinical practice. We performed a nationwide survey to examine the attitudes of Japanese obstetricians toward the use of assays for antiphospholipid antibodies (aPLs).

METHODS

A questionnaire was sent to 2,700 obstetric facilities where maternity checkups are carried out. The types of assays conducted for aPLs, ascertainment of persistence of the antibodies for at least 12 weeks, and the cutoff points used for the assays were examined.

RESULTS

Of the facilities surveyed, 61.5% carried out the assay(s) only once. In regard to the type of assay performed, 97.1% carried out the assay for aCL IgG and/or β2GPI-dependent aCL, while 67.9% performed the LA-aPTT and/or LA-RVVT assay. Only 8.8% carried out assays for both LA. As for the cutoff points used, 98% of the facilities used lower cutoff points described in the manufacturers' manuals rather than the cutoff values recommended in the CC.

CONCLUSION

Thus, only a limited number of facilities adhered precisely to the CC for the diagnosis of APS. Inappropriate treatment and unnecessary expense are potentially major concerns when facilities overdiagnose APS using lower cutoff points or without ascertaining the persistence of the antibodies for at least 12 weeks. On the other hand, some patients miss the opportunity to be treated for APS because of the absence of testing for LA.

Incidence of anticardiolipin antibodies and lupus anticoagulant factor among women experiencing unexplained recurrent abortion and intrauterine fetal death

The aim of this research study was to estimate anticardiolipin (IgG & IgM) antibodies (aCL) and lupus anticoagulant (LA) factor in patients of recurrent unexplained pregnancy loss and intrauterine fetal deaths (IUFD). 82 women were selected for this study by virtue of having more than two consecutive unexplained pregnancy losses in their first trimester and were referred by the department of Obstetrics and Gynecology, King Saud Medical City Hospital, Riyadh, KSA. All patients had gone through a standardized investigation sequence. Lupus anticoagulants and Anticardiolipin antibodies (IgM and IgG) were detected in the serum by the enzyme linked immunosorbent assay method. To check the significance of aCL and LA, two-tailed t-test was done. Non parametric data was calculated either by Chi-Square test or Fischer exact test when relevant. Total 82 females grouped as 52 cases of recurrent (≥2) mainly first and second trimester miscarriage and 30 cases of recurrent (≥2) late intrauterine fetal death. Lupus anticoagulants was observed in twenty one (21) cases (25.6%) while anticardiolipin antibodies IgM and or IgG positive cases were estimated in forty four (44) cases (53.65%). The prevalence of APS in both studied group was thirty five (35) cases (42.68%). Antiphospholipid antibodies are calculated as the most important reason for recurrent abortion. The patients with unexplained recurrent pregnancy loss must be advised to go for a screening test for all this aPL antibodies.

Antiphospholipid antibody testing and standardization

The laboratory criteria that define patients with antiphospholipid syndrome (APS) include lupus anticoagulant (LAC), anticardiolipin antibodies and anti-β2 glycoprotein I antibodies (aβ2GPI). All assays show methodological shortcomings and the combination of the three tests, each with different sensitivity and specificity, and hence, differences in clinical utility make the laboratory diagnosis of APS challenging. Consensus guidelines and proposals for antiphospholipid antibodies (aPL) testing have been published in the last 20 years and have led to a substantial improvement. Despite efforts so far, standardization is not reached yet, but progress has been made. On-going efforts to reduce the interlaboratory/interassay variations remain important; even an absolute standardization cannot be feasibly achieved. Taking into account the methodological shortcomings of the means we have available, more detailed guidelines may help in adequate performance of aPL testing. This review will focus on the efforts and achievements in standardization and on the weaknesses and strengths of the current available laboratory methods.

My contribution, my dream - a look at the future of APS

We found, in 1994, that the epitope for anticardiolipin antibodies (aCL) developed when β2-glycoprotein I (β2GPI) was adsorbed on polyoxygenated polystyrene plates. We also found, in 2009, that the cleaved form of β2GPI (nicked β2GPI) was bound to angiostatin 4.5 and attenuated its antiangiogenic property. We described in 2000 that antiprothrombin antibodies were bound to prothrombin exposed to immobilized phosphatidylserine (aPS/PT) and more than 95% of antiphospholipid syndrome patients who were positive for aPS/PT had lupus anticoagulant. We demonstrated that in the cells stimulated by human monoclonal anti-β2GPI antibodies, p38 mitogen-activated protein kinase phosphorylation was observed in the presence of β2GPI. Furthermore, we found that complement activation was essential for thrombus formation in patients with the antiphospholipid syndrome in vivo.

Warfarin monitoring in antiphospholipid syndrome and lupus anticoagulant

OBJECTIVE

To review the available literature on international normalized ratio (INR) and chromogenic factor X (CFX) monitoring in patients with antiphospholipid syndrome (APS), specifically lupus anticoagulant (LA), and furthermore, to identify benefits of one monitoring test compared with the other in the presence of LA.

DATA SOURCES

A literature search was conducted through MEDLINE (1946-May 2014) utilizing the following MeSH terms chromogenic compounds, anticoagulants, and factor X. Further articles were identified from original literature citations.

STUDY SELECTION

All English-language studies were included that involved INR and/or CFX monitoring in APS patients that focused on a therapeutic anticoagulation level with warfarin therapy.

DATA SYNTHESIS

A total of 55 articles were identified, of which nine are referenced because of their relevance for this review: three articles focus on the efficacy of utilizing INR monitoring in patients with APS, five focus on CFX compared with INR for therapeutic warfarin dosing, and one compares different thromboplastins utilizing both INR and CFX monitoring. INR monitoring in patients with APS, specifically LA, was not found to be reliable because thromboplastin reagents are sensitive to LA. Furthermore, when INR was compared to CFX, patients with LA had supratherapeutic INRs despite having CFX within goal range.

CONCLUSIONS

In a subgroup of APS patients, INR monitoring may not be safe for determining the dose of warfarin because their INR values can be falsely elevated. Although CFX monitoring is more accurate, it too comes with its own downsides. Managing warfarin therapy in the APS population needs to be individualized.