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Background: D-dimer testing may help deciding the duration of anticoagulation in subjects at high risk of venous thromboembolism (VTE) recurrence. Two management studies on this issue have been published (DULCIS in 2014 and APIDULCIS in 2022). They had similar designs but had important different results. Aim of this article is to compare their results., Methods: Both studies were finalized to extend anticoagulation [with vitamin K anticoagulants (VKAs) in DULCIS or apixaban 2.5 mg BID (kindly provided by BMS-Pfizer Collaboration) in APIDULCIS] only in patients with positive D-dimer results., Results: More D-dimer assays resulted positive in APIDULCIS than in DULCIS (61.1 % vs 47.7 %, respectively; p < 0.0001). While only 4 (0.5 %) refused low dose apixaban in APIDULCIS, the 22.6 % of patients with positive D-dimer refused to resume VKAs in DULCIS; their rates of recurrence were 187 and 8.8 per 100 person-years, respectively (incidence rate ratio [IRR]: 21.2). The incidence of bleeding was low in those receiving apixaban vs those who resumed VKAs (0.4 vs 2.3 per 100 person-years, respectively; IRR 0.17;). While the recurrence rate was low and similar in the studies in subjects who resumed anticoagulation, it was significantly higher in APIDULCIS than in DULCIS in those who stopped anticoagulation for negative D-dimer (5.6 vs 3.0 per 100 person-years, respectively; IRR 1.9)., Conclusion: The low dose Apixaban for extended VTE treatment is effective and safe, and well accepted by patients. Why subjects who stopped anticoagulation for negative D-dimer had a higher recurrence rate in APIDULCIS than in DULCIS remains to be explained., Competing Interests: Declaration of competing interest BC declares speakers' fees from Techdow and from Werfen; all other authors declare no competing financial interests., (Copyright © 2024. Published by Elsevier Ltd.)

Background: Anti-phosphatidylserine/prothrombin (aPS/PT) antibodies are the major contributor to activated Protein C resistance (APC-R) in tetra-positive thrombotic high-risk patients with Antiphospholipid Syndrome (APS)., Objectives: To evaluate the role of phospholipids (PL) on aPS/PT mediated APC-R., Patients/methods: Total IgG were purified from plasma of 6 tetra-positive patients and IgG aPS/PT were affinity-purified from 3 of these patients. Purified material was spiked into Normal Pooled Plasma (NPP) and tested for APC-R in thrombin generation assay and in Factor Va inactivation assay using increasing amounts of phospholipids., Results and Conclusions: Total IgG showed APC-R at low PL concentration (1.5 μg/mL) that disappeared at increasing PL concentrations (5.8, 11.6 and 46.6 μg/mL). In the same way, affinity purified aPS/PT showed a robust (59 %, 52 %, 36 %) APC-R in patients #4, #5 and #6, respectively at low PL concentration (1.5 μg/mL) that was completely reversed at higher concentration (11.6 μg/mL). The inactivation of FVa by activated Protein C (aPC) was impaired in the presence of aPS/PT at low aPL concentration and reversed by increasing amounts of PL. These data point out the relevance of PL in reversing APC-R in this 'in vitro' system. The mechanism for reversal might be explained by loss of PL availability for aPC. These results may give some insight into the pathogenesis of thrombosis or suggestions for alternative treatments., Competing Interests: Declaration of competing interest Prof. Vittorio Pengo received lecture fees from Werfen Group, Milan Italy., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the presence of antiphospholipid antibodies (aPLs) and thrombotic events. The association of aPLs with thrombotic events depends on the number of positive tests. Besides the three classical tests to classify APS, phosphatidylserine/prothrombin complex autoantibodies (aPS/PT) are increasingly used to better define this condition. The aim of this systematic review was to evaluate the prevalence of aPS/PT in general and according to antiphospholipid antibody profiles in patients with APS., Methods: A systematic search of PubMed, Web of Science, and the Cochrane Library from January 1990 to September 2021 was carried out according to PRISMA guidelines. Proportions and 95% confidence intervals (CIs) were calculated using random-effects model. Publication biases were evaluated via visualization of funnel plots along with Egger's and Begg's tests., Results: Twenty-one articles about the prevalence of aPS/PT in 1853 patients with APS were deemed eligible and analyzed according to the inclusion criteria. Pooled prevalence of aPS/PT IgG alone, IgM alone, and IgG/M were 50.0%, 45.0%, and 65.0%, respectively. No significant publication bias was detected from funnel plots or Egger's and Begg's tests. When the prevalence of aPS/PT was calculated in homogeneous aPLs, a much higher rate of pooled prevalence of aPS/PT IgG/M in patients positive for Lupus Anticoagulant (84.5%) and in those with triple positivity (83.4%) was found., Conclusions: These data show a high rate of aPS/PT positivity in patients with APS (especially in those positive for LAC) but further studies are needed to ascertain whether this test might be useful in the laboratory classification criteria of APS., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: The APS ACTION International Clinical Database and Repository includes a secure web-based data capture system storing patient information including demographics, antiphospholipid antibodies (aPL)-related medical history, and aPL tests. Despite efforts at harmonization, inter-assay variability remains a problem in aPL testing. As a clinical repository open to researchers, ensuring comparability between assays and consistency in results between APS ACTION laboratories is essential to the validity of studies emerging from this network., Objective: To assess the level of agreement between an aPL-registry inclusion and core laboratory (core lab) anticardiolipin antibody (aCL) and anti-β 2 -glycoprotein-I antibody (aβ 2 GPI) ELISA testing results., Methods: Patients are recruited from 25 international centers based on positive aPL tests at inclusion. All samples are retested at the corresponding national APS ACTION core lab to confirm aPL positivity based on standard validated protocols. We analysed the categorical agreement, degree of linear association, and correlation between inclusion (local laboratory) and core lab aPL tests. Samples were included in this study only if results of aPL testing with ELISA at baseline were available., Results: 497 registry samples underwent confirmatory aPL tests. Categorical agreement between the inclusion and core lab values, as expressed by Cohen's kappa coefficients, ranged between 0.61 and 0.80 (as substantial agreement). The correlation between quantitative results in the aCL and aβ 2 GPI was better for IgM and IgA compared to IgG (Spearman rho 0.789 and 0.666 vs. 0.600 for aCL and rho 0.892 and 0.744 vs. 0.432 for aβ 2 GPI)., Conclusions: The results of inclusion for aCL and aβ 2 GPI tests used for recruitment into the registry were in agreement to the results obtained by the APS ACTION core laboratories; aCL and aβ 2 GPI results showed very good categorical agreement. This agreement increased when considering high titer (>40 units) samples. APS ACTION is a reliable and useful research resource for APS., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Whether antibodies directed to β2-Glycoprotein I (aβ2GPI) are responsible for LA activity is not well defined. However, in the absence of such antibodies the molecule responsible for LA phenomenon is unknown., Objective: The aim of this study was the biochemical identification of the target antigen epitope of aPL responsible of LA activity in the absence of aβ2GPI antibodies together with the biological and clinical characteristics of these patients in comparison with classical triple positive patients., Patients/methods: A comparison of patients with LA without (LA+/aβ2GPI-) and those with (LA+/aβ2GPI+) associated aβ2GPI antibodies was performed. Size exclusion chromatography and analytical chromatography were used to identify the molecule with LA activity in patients LA+/aβ2GPI-., Results and Conclusions: Analytical size-exclusion chromatography revealed a peak of 996Kd with LA activity perfectly overlapping that of IgM anti phosphatidylserine/prothrombin (aPS/PT) antibodies. Similarly, all the 25 LA+/aβ2GPI- patients were positive for aPS/PT antibodies. LA+/aβ2GPI- compared to 33 LA+/aβ2GPI+ patients turned out to be significantly older, with a lower rate of previous thromboembolic events and a weaker LA activity. Search for aPS/PT and aβ2GPI antibodies in patients with LA is useful to identify two subgroups of LA at different risk of thromboembolic events., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Antiphospholipid Syndrome (APS) is a condition characterized by the occurrence of thromboembolic events and/or pregnancy loss combined with one laboratory criterion among Lupus Anticoagulant- LAC, anticardiolipin -aCL, and anti β2-Glycoprotein I -aβ2GPI antibodies. Several hypotheses were put forward to explain the causal role of antibodies in the clinical events but none is fully convincing. Current laboratory diagnosis is based on three tests (LAC, IgG/IgM aβ2GPI and IgG/IgM aCL antibodies). The triple-positive profile (all the three tests positive, same isotype) is associated with a higher risk for thrombosis. The mainstay of therapy in thrombotic APS is anticoagulation, with VKAs being the cornerstone. Low dose aspirin in combination or alone may have a role in arterial thrombosis, and in primary thromboprophylaxis. The Non-Vitamin K Antagonists Oral Anticoagulants (NOACs) role in the therapy of APS is under investigation but not verified. Alternative treatment options including rituximab and eculizumab have been successfully reported in few cases of catastrophic APS., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Non-vitamin K antagonist oral anticoagulants (NOACs) do not need routine laboratory monitoring but measurement of drug concentration is important in emergency conditions. Specific laboratory tests are not readily available or not implemented in every hospital. Point-of-Care Tests (POCT) may bridge this gap and be used as a bedside solution., Objectives: Feasibility of POCT to assess plasma levels of dabigatran, rivaroxaban and apixaban., Patients/methods: Activated Coagulation Time-Low Range (ACT - LR) using a portable Hemochron Signature Elite for dabigatran and prothrombin time (expressed as INR) by Coaguchek XS Pro for rivaroxaban and apixaban were obtained at trough and peak in 136 consecutive patients taking NOACs (70 on dabigatran, 45 on rivaroxaban and 20 on apixaban). Using a paired study design, drug concentrations were concurrently determined by functional specific tests., Results and Conclusions: The correlation between NOACs concentration and the values obtained using the POCTs was high for dabigatran and rivaroxaban (r = 0.80 and r = 0.82, respectively) and low for apixaban (r = 0.21). ACT-LR ≤ 188 s better detected dabigatran levels ≤ 50 ng/ml, with a sensitivity of 87.5% and a specificity of 84.1%. ACT-LR values > 217 s better discriminated value of dabigatran > 200 ng/ml, with a sensitivity of 86.7% and a specificity of 81.4%. INR Coaguchek values ≤ 1.2 better identified patients with rivaroxaban values < 100 ng/ml, with sensitivity of 90%, specificity of 88.5%. This analysis was not possible for apixaban., Conclusion: In emergency situations POCT use may provide useful immediate information on dabigatran and rivaroxaban concentration., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: The optimal long-term strategy for preventing recurrent venous thromboembolism (VTE) in patients with deep-vein thrombosis (DVT) is uncertain., Methods: In 620 consecutive outpatients with a first proximal DVT who had completed at least three months of anticoagulation (unprovoked in 483, associated with minor risk factors in 137), the ultrasound presence of residual vein thrombosis (RVT) was assessed and defined as an incompressibility of at least 4mm. In 517 patients without RVT and with negative D-dimer, anticoagulation was stopped and D-dimer was repeated after one and three months. Anticoagulation was resumed in 63 of the 72 patients in whom D-dimer reverted to positivity., Results: During a mean follow-up of three years, recurrent VTE developed in 40 (7.7%) of the 517 patients, leading to an annual rate of 3.6% (95% CI, 2.6 to 4.9): 4.1% (95% CI, 2.9 to 5.7) in individuals with unprovoked DVT, and 2.2% (95% CI, 1.1 to 4.5) in those with DVT associated with minor risk factors. Of the 233 males with unprovoked DVT, 17 (7.3%) developed events in the first year of follow-up. Major bleeding complications occurred in 8 patients while on anticoagulation, leading to an annual rate of 1.2% (95% CI, 0.6 to 2.4)., Conclusions: Discontinuing anticoagulation in patients with a first episode of proximal DVT based on the assessment of RVT and serial D-dimer leads to an overall annual rate of recurrent VTE lower than 5.0%, which is the rate deemed as acceptable by the Subcommittee on Control of Anticoagulation of the ISTH. However, in males with unprovoked DVT there is room for further improving the long-term strategy of VTE prevention. (ClinicalTrials.gov number, NCT01285661)., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Introduction: Idiopathic venous thromboembolism (VTE) is associated with the risk of cancer but the risk factors for cancer development in such patients are still uncertain., Aim: To assess risk factors for the development of cancer after a standard course of anticoagulation in patients with first episode of idiopathic VTE., Materials and Methods: Subjects were enrolled in the three large prospective multicentre studies: PROLONG (NEJM 2006) PROLONG II (Blood 2010) and DULCIS (Blood 2014). Women whose index event was hormone related were excluded from the analysis. The development of cancer was recorded during a 2-year follow-up., Results: 1,805 patients were enrolled (M/F: 510/453), mean age: 62, median: 67; range:18-87 years). Cancer developed in 55 patients (3% ; 1.7% pt-years) of whom 15 (2.0%; 1.1% pt-years) had PE with or without DVT and 40 (3.8%; 2.1% pt-years) had DVT without PE (p=0.03). The development of cancer was associated with DVT without PE (HR:1.8; 95% CI: 1.1-3.3) and age >65 (HR: 2.5; 95%: 1.3-4.9). Among patients with DVT, with or without PE, the development of cancer was associated with the presence of residual vein obstruction>4mm (RVO) at compression ultrasound (HR: 1.8, 95% CI: 1.1-3.3) and age>65 (HR: 2.8; 95% CI: 1.3-6.2)., Conclusions: Age>65 years, DVT without PE and the presence of RVO are significantly associated with the risk of developing cancer after a first episode of idiopathic VTE over a two-year follow-up., (© 2016 Elsevier Ltd. All rights reserved.)

Introduction: Direct oral anticoagulant (DOAC) intra- and inter-individual variability was previously reported, but its magnitude is still considered negligible for patient management., Objective: To evaluate inter- and intra-individual variability in real-world atrial fibrillation patients on dabigatran, rivaroxaban or apixaban in four Italian anticoagulation clinics and to assess the correlation between DOAC plasma concentration and creatinine-clearance (CrCl)., Materials and Methods: A total of 330 consecutive patients were enrolled, of which 160 were on dabigatran (70 and 90 taking 150 mg or 110 mg twice-daily, respectively), 71 on rivaroxaban (37 and 34 taking 20mg or 15 mg once-daily) and 99 on apixaban (73 and 26 taking 5mg or 2.5mg twice-daily). Blood was taken at trough and peak within the first month (15-25 days) of treatment. Diluted-thrombin-time (dTT) calibrated for dabigatran and anti-FXa calibrated for rivaroxaban or apixaban was performed., Results: Mean inter-individual variability expressed as overall CV values for all drugs was lower at peak (CV=46%) than at trough (CV=63%). Mean CV% intra-individual variability was 36.6% at trough and 34.0% at peak. Correlation with CrCl was poor for all drugs and only dabigatran at trough showed a significant correlation., Conclusion: This multicenter study confirms high DOAC inter-individual variability that cannot be explained by the rate of renal clearance to which the three DOAC were subjected since the correlation with CrCl was relatively poor. This poor correlation suggests caution in using CrCl as the sole laboratory parameter to indirectly evaluate residual circulating DOAC., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Determination of the three recommended tests for the diagnosis of antiphospholipid syndrome [Lupus Anticoagulant (LA), anticardiolipin (aCL) and anti β2-Glycoprotein 1 (aβ2GP1) antibodies] allow physicians to allocate patients into classification (risk) categories., Objectives: To measure antibodies of IgG isotype directed towards Domain 4/5 (Dm4/5) of β2GP1., Patients/methods: In this cross-sectional study we measured IgG aβ2GP1-Dm4/5 in a group of individuals positive for IgG aβ2GP1 and classified as triple (LAC+, IgG aCL+, IgG aβ2GP1+, n=32), double (LAC-, IgG aCL+, IgG aβ2GP1+, n=23) or single positive (LA-, IgG aCL-, IgG aβ2GP1+, n=10)., Results: Geometric mean and standard deviation of IgG aβ2GP1 values expressed as Chemiluminescent Units (CU) in triple, double, single positive groups and in 40 healthy individuals were 1795±783, 321±181, 29±8 and 5.0±1.0, respectively (ANOVA p<0.0001). Geometric mean and standard deviation of IgG aβ2GP1-Dm4/5 expressed as Optical Density (OD) in triple, double and single positive groups and in 40 healthy individuals were 0.16±0.13, 0.16±0.15 and 0.26±0.15, 0.13±0,11, respectively (ANOVA p<0.002). Individuals in the single positive group, expressed significantly higher values with respect to triple (p=0.04) and double (p=0.03) positive groups. Approximate OD cut-off value (99° percentile) calculated in 40 normal control subjects is 0.404. Positivity to IgG aβ2GP1-Dm4/5 according to this cutoff was found in only 5 individuals, 3 in triple positive and 2 in single positive groups and was not associated with thromboembolism., Conclusion: Mean level of IgG aβ2GP1-Dm4/5 is higher in single positive group. There is no association between positivity to IgG aβ2GP1-Dm4/5 and thromboembolic events., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Among the so called antiphospholipid (aPL) antibodies Lupus Anticoagulant (LAC) is considered the strongest risk factor for thromboembolic events. In individuals without a previous thromboembolic event (carriers), LAC is a risk factor when associated with the presence of anticardiolipin (aCL) and aβ2-Glycoprotein I (aβ2GPI) antibodies. On the other hand, data on carriers of isolated LAC positivity are sparse and inconclusive. The aim of this study was to prospectively determine the incidence of thrombosis in a cohort of carriers of isolated LAC positivity. One-hundred seventy-nine carriers of LAC confirmed twelve weeks apart and in a reference laboratory were studied. During a total follow up of 552 person-years, there were seven thromboembolic events (1.3% person-y). All the seven patients had at least one adjunctive major risk factor for thrombosis. The cumulative incidence of thromboembolic events was 3.1% (95% CI 0.6-5.6) after 2years, and 5.9% (95% CI 1.2-10.6) after 5 and 10years. On a multivariate regression analysis considering age, sex, autoimmune disease, risk factors for arterial and venous thrombosis, use of aspirin, only age was found to be an independent predictor of thromboembolic events (HR=1.1, 95% CI 1.0-1.2, p=0.02). These data might be relevant in clinical practice and underline the importance of differentiating LAC carriers in terms of isolated positivity or positivity associated with the presence of antibodies to aCL and β2-glycoprotein I., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Within-individual biological variation of INR (CV(B)) was assessed in 245 selected stable warfarin-treated patients monitored by three thrombosis centers. Selection criteria were: treatment period of six months or longer before the observation period; at least six consecutive INRs within the therapeutic range of 2.0 - 3.0; interval between consecutive INR measurements of two weeks or longer; no change in warfarin dose; no changes in the patient's circumstances which may influence the INR, such as intercurrent diseases, invasive procedures, starting or stopping drugs interacting with warfarin. The minimum, maximum and mean within-individual coefficient of variation CV(B) of the INR measurements in the 245 selected patients were 0.4%, 14.5%, and 9.0%, respectively Analytical performance goals for the INR measurement (imprecision) could be derived from the mean CV(B). For a therapeutic range of 2.0 - 3.0 with warfarin, the desirable and optimum imprecision of INR determination is <4.5% CV and <2.25% CV, respectively. The biological variation and analytical performance goals have been derived using classic laboratory methods but should be applicable to point-of-care testing as well., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Introduction: Antiphospholipid Syndrome (APS) is characterized by the presence of circulating antiphospholipid antibodies in patients with thrombosis or pregnancy morbidity. Antibodies involved in these disorders are mainly those directed against β(2)-Glycoprotein I (β(2)GPI) with the major epitope apparently located on discontinuous antigen with several parts of Domain I (DmI) involved. The relation between anti-DmI antibodies and patients' risk categories is unknown., Materials and Methods: The synthetic full-length and correctly-folded DmI (1-64) to set up a competitive inhibition enzyme-linked immunoadsorbent assays (ELISA) was used. Plasma of 22 patients with APS and triple positivity [Lupus Anticoagulant positive (LAC+), IgG anti-cardiolipin positive (aCL+), IgG anti-β(2)GPI positive (a β(2)GPI +)], 15 with double positivity (IgG aCL+, IgG aβ(2)GPI+), 9 with single positivity (IgG aβ(2)GPI+) and 20 controls were evaluated., Results: Median of percentage inhibition was 25.5% [interquartile range (IQR)17.2-33.0] in triple positive patients. Significantly lower inhibition was observed in patients with double positivity, median inhibition 5.0% (IQR 0.0-27.0) and in patients with single positivity median inhibition was 2.0% (IQR 0.5-8.0) (p<0.0001). No inhibition was detected in control subjects or using β(2)GPI peptides (40-52 and 57-70), or when antithrombin, an insignificant control protein was used., Conclusions: High risk patients with APS and triple laboratory positivity as compared with double and single positivity patients have significantly higher titre of anti-DmI antibodies as evaluated by an inhibition test., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Results for lupus anticoagulant (LA) are currently expressed as ratio of patient-to-normal clotting times (LA-ratio). Yet, numerical results do vary according to the method used for testing, thus making difficult the between-method comparison of results. We hypothesized that the standardization model currently used for the INR for patients on oral-anticoagulants (OAT) would be of value also for LA standardization., Patients and Methods: To test this hypothesis we determined a sensitivity index valid for LA (called LASI) for six LA-detection methods against a common-standard using two sets of calibration-plasmas: (i)normal-plasmas spiked with IgG derived from patients strongly-positive for LA or (ii)plasmas from LA-positive patients. The LASI was then used to convert the LA-ratio into the standardized-LA-ratio (SLA-ratio) according to the equation: SLA-ratio = (LA-ratio)(LASI)., Results: We demonstrate that (i)the model is feasible because calibration plots of log-transformed clotting times obtained for the LA-detection methods-vs.-the common-standard gave acceptable LASI values; (ii)the model is effective because between-method variability expressed as coefficient of variation, which was 42.8% with results expressed as LA-ratio, decreased to 7.8% with results expressed as SLA-ratio; (iii)the LASI value calculated with the LA-positive plasmas is more effective in minimizing between-method variability than the LASI value calculated with IgG-spiked plasmas., Conclusions: A model of LA calibration similar to the INR for patients on OAT is feasible by using plasmas from LA-positive patients instead of patients on OAT. Potential application of the model are:(i)to compare the relative responsiveness of different LA-detection methods,(ii)to minimize differences between their results and (iii)to quantify LA potency., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Because the diagnosis of antiphospholipid syndrome is based on laboratory data, performance and interpretation of such tests is essential. Positivity in a single test among Lupus Anticoagulant (LA), anti cardiolipin (aCL) and anti β2-glycoprotein I (aβ2GPI) antibodies calls APS diagnosis into question. Conversely, triple positivity is strongly associated to thrombosis and pregnancy morbidity. A new era in studying APS should take into account different antiphospholipid antibodies profiles. Clinical studies on groups of patients that are homogeneous in terms of laboratory tests will provide information on the real risk of patients and on the real effect of therapeutic interventions., (© 2011 Elsevier Ltd. All rights reserved.)

Objective: Anti-prothrombin (aPT) antibodies have been found in Lupus Anticoagulant (LA) positive patients. Their prevalence and relative contribution to thromboembolic risk in LA-positive patients is not well defined. The aim of this study was to determine their presence and association with thromboembolic events in a large series of patients with confirmed LA., Methods: Plasma from LA-positive patients was collected at Thrombosis Centers and sent to a reference central laboratory for confirmation. Positive plasma was tested using home-made ELISA for the presence of aPT and anti-beta(2)GPI antibodies., Results: LA was confirmed in 231 patients. Sixty-one of 231 (26%, 95%CI 22-33) LA positive subjects were positive for IgG aPT and 62 (27%, 95% CI 21-33) were positive for IgM aPT antibodies. Clinical features of Antiphospholipid Syndrome (APS) were not associated with the presence of IgG aPT [43 APS in 61 (70%) positive and 109 APS in 170 (64%) negative IgG aPT subjects, p=ns] or IgM aPT. Rate of positivity of IgG and IgM a beta(2)GPI was significantly higher than that of IgG and IgM aPT. Clinical events accounting for APS occurred in 97 of 130 (75%) IgG a beta(2)GPI positive and in 55 of 101 (54%) IgG a beta(2)GPI negative patients (OR 2.4, 95% CI 1.4 to 4.3, p=0.002). No significant association with clinical events in patients positive for both IgG aPT and IgG a beta(2)GPI as compared to those positive for one or another test was found. When patients negative for both IgG aPT and IgG a beta(2)GPI (LA positive only) were compared with remaining patients, a significantly lower association with clinical events was found (OR=0.4, 95% CI: 0.2 to 0.7, p=0.004)., Conclusions: As compared to IgG a beta(2)GPI, the prevalence of IgG aPT in patients with LA is significantly lower and not associated with the clinical features of APS., ((c) 2010 Elsevier Ltd. All rights reserved.)

The relation of cancer to thromboembolism has been described since the mid 1800s. Different studies in animal and in vitro models have confirmed the link between the haemostatic system and both tumor stroma formation and metastasis. Although the mechanisms of warfarin effects on cancer are not elucidated, but are based on hypothesis, various studies have reported interesting results in this setting. But does warfarin added to recommended anti-tumour therapy improve survival of cancer patients? For the time being it is difficult to answer this question. Data from the literature are few and sometimes contradictory. Trials are characterized by important differences in studied cohorts, histological types of cancers evaluated, and in the treatment protocols. Most studies show that there is benefit from the addition of warfarin to chemotherapy in the tumour development, expansion and on the patient survival, especially in particular types of cancers. These data, although fascinating, do not rationalize the use of anticoagulation in the routine prophylaxis of cancer, however, they call for efforts in preparing large scale randomized trials to elucidate the effect of anticoagulation in the setting of neoplastic disease.

Background: A relationship between antibody profile and pregnancy outcome in patients with a previous diagnosis of primary antiphospholipid syndrome (APS) has not been clearly documented., Methods: Women attending our Center with primary APS characterized by the presence in the blood of one or more of the following: Lupus Anticoagulant (LA), IgG/IgM anticardiolipin (aCL), IgG/IgM anti-human beta2-Glycoprotein I (abeta2GPI) antibodies (confirmed after a minimum of 3 months) were considered eligible for this study. Women who became pregnant during the study period with the exception of those with congenital thrombophilia or other congenital abnormalities were included in our analysis. Primary outcome events, defined as early abortion or fetal death, were evaluated in relation to the laboratory classification category assigned to each patient at the time they were diagnosed with APS., Results: A total of 97 pregnancies occurring in 79 primary APS patients during the study period were analyzed. Twelve out of 97 pregnancies were unsuccessful, 11 out of 65 (16.9%) in category I patients (more than one positive laboratory test) and 1 out of 32 (3.1%) in category II patients (single positive test; adjusted hazard ratio 1.9; 95% CI, 0.2 to 18.9, p=0.6). Pregnancy loss took place in 10 out of 19 pregnancies (52.6%) in women belonging to category I with triple positivity and in 1 out of 46 pregnancies (2.2%) in patients with double positivity. The rate of pregnancy loss was more frequent in the 19 pregnancies of patients with triple positivity than in the 46 pregnancies of double positive patients (adjusted hazard ratio 23, 95% CI, 1.3 to 408, p=0.03)., Conclusion: Poor pregnancy outcomes occur more frequently in category I than in category II primary APS patients. However, it has been seen that a greater predictability is achieved when category I patients are grouped into triple and double positivity states.

Introduction: Primary antiphospholipid antibody syndrome (PAPS) is characterized by venous or arterial thrombosis and positive antiphospholipid antibodies. It is controversial whether PAPS patients have early atherosclerosis. Endothelial dysfunction is an early event in the natural history of atherosclerosis. Aim of our study was to compare endothelial function of patients with PAPS and no associated risk factors with that of age- and sex-matched controls., Materials and Methods: Patients with PAPS, carefully selected to exclude all known risk factors for cardiovascular diseases, estrogen therapy, pregnancy, intake of drugs affecting endothelial function, vitamins or antioxidants, were included in a case-control study. Controls were age- (+/-5 years) and sex-matched subjects with the same exclusion criteria but without PAPS. Flow-mediated dilation of the brachial artery and some plasmatic markers of endothelial and platelet activation were measured. Measures are expressed as mean+/-SEM., Results: Twenty cases (mean age 42+/-4.0 years, 11 females) and 39 controls (mean age 41+/-2.9, 22 females) were studied. FMD was 5.7+/-0.8% in cases (95% CI: 4.1 to 7.3) and 6.8+/-0.5% (5.7 to 7.9) in controls (p=NS). Plasma von Willebrand factor was 128+/-11.3% and 134.2+/-16.1% in cases and controls, respectively (p=NS). Soluble P-selectin and soluble CD40L were 94.1+/-4.9 ng/ml and 0.7+/-0.1 ng/ml in cases and 87.7+/-4.0 ng/ml and 1.0+/-0.2 in controls, respectively (p=NS). In a substudy, circulating progenitor and mature endothelial cells were comparable between the two groups., Conclusions: Endothelial function in patients with PAPS and no associated risk factors is similar to that of age- and sex- matched controls. These data suggest that the alterations leading to thrombosis in PAPS concern primarily the clotting system.

It has been reported that IgG to oxidized LDL/beta2-glycoprotein I (oxLDL/beta2GPI) complexes are associated with arterial thromboembolism (TE) in patients with antiphospholipid syndrome (APS). How these antibodies behave in arterial as compared to venous TE in APS is unknown. The aim of the present study was to evaluate the association of IgG anti-oxLDL/beta2GPI with clinical manifestations in category I APS patients. Fifty-seven APS patients with triple positivity (Lupus Anticoagulant (LAC), anti cardiolipin (aCL) and anti-beta2-glycoprotein I (abeta2GPI) antibodies), 28 with arterial and 29 with venous thromboembolism, were included in the study. There were no differences in the dRVVT ratio, IgG/IgM aCL and IgG/IgM abeta2GPI titers in the two patient groups. There were no differences in the IgG (78.5 U+/-59.8 vs. 112.2 U+/-92.3) and IgM (16.3 U+/-15.9 vs. 21.1 U+/-14.3) anti-oxLDL/beta2GPI mean values. A significant correlation was found between IgG anti-oxLDL/beta2GPI and IgG anti-beta2GPI titers in the whole group of APS patients. Patients in the arterial group were older and had more risk factors for atherosclerosis. Data from this study do not support the hypothesis that IgG anti-oxLDL/beta2GPI are specifically associated to arterial TE in Category I APS patients.

Lupus anticoagulant (LA) and anticardiolipin (aCL) antibodies are the classical tests used to diagnose the antiphospholipid syndrome (APS). Unfortunately, since these are nonspecific and standardization is lacking, the results of laboratory work-ups upon which diagnosis are made are often misleading. The performance of clinical laboratories in detecting LA using lyophilised affinity purified immunoglobulin has been previously reported. The same material was used to investigate the inter-laboratory variability of aCL and anti-beta(2)-Glycoprotein I (beta(2)-GPI) antibody measurements. Laboratories were asked to test normal plasma spiked with purified IgG or distilled water in order to obtain 3 samples positive for aCL and anti-beta(2)-GPI at different antibody concentration (A, B and C) and 3 samples of normal plasma. Thirty-five laboratories participated and interpreted their test results. All performed an ELISA for IgG aCL antibodies, while 17 also tested samples using IgG anti-beta(2)-GPI antibody ELISA. Sensitivity and specificity were calculated on the basis of the responses provided by each laboratory. Overall, 99/105 samples were correctly interpreted as positive and 97/101 as negative for the presence of IgG aCL, corresponding to a sensitivity and specificity of 94% and 96%, respectively. Likewise, 46/51 samples were correctly defined as positive and 50/51 as negative for the presence of IgG anti-beta(2)-GPI corresponding to a sensitivity and specificity of 90% and 98%, respectively. A wide variability in results pertaining to the positive samples was found for aCL-ELISA (coefficient of variation of 79%, 59%, and 53% for samples A, B, and C, respectively) as well as for abeta(2)-GPI-ELISA (coefficient of variation of 85%, 95%, and 50% for samples A, B, and C, respectively). This was confirmed when the analysis was restricted to those centres using the same commercial kit. Median antibody concentrations reported by centres for positive samples were consistent with the prolongation of coagulation tests assessing lupus anticoagulant (LA). Among these, dRVVT showed a good sensitivity and linear correlation with aCL antibody concentration. In conclusion, on the whole this survey found correct interpretation of positive and negative samples by both ELISAs. Nonetheless the high variability of reported data remains a major problem that only a consensus on the part of laboratories and manufacturers to utilize standard, uniform materials and procedures can hope to overcome.

A portable prothrombin time (PT) monitor allows patients on oral anticoagulant therapy (OAT) to measure their PT at home. The purpose of the study was to evaluate the accuracy and precision of a portable PT monitor (Coagucheck, Roche Diagnostics, Mannheim, Germany) as compared with laboratory methods. The prospective study was conducted in four centers of the Italian Federation of Anticoagulation Clinics. A one-month instruction phase was followed by a six-month surveillance phase. Seventy-eight subjects on stable OAT (48 men, 30 women, age range: 18-75) were selected on a volunteer basis. Dual measurements of INR values were performed in each subject both from finger capillary blood by the monitor and from venous blood by the Anticoagulation Clinic laboratory in three instruction sessions. The mean difference (bias) of the monitor INR results when compared with the average of laboratory INR and monitor INR results was -0.025 (limits of agreement-LA: -0.84/+0.81 INR units). The mean bias was -0.0675 (LA: -0.37/+0.23), +0.018 (LA: -0.39/+0.35), and +0.039 (LA: -0.49/+0.55), respectively, for INR values lower than 2.0, between 2.0 and 3.0, and greater than 3.0. The overall precision coefficient of monitor INR was 0.370, while it was 0.23, 0.46, 0.29, and 0.21, respectively, in Centers 1, 2, 3, and 4. The overall variation coefficient was 6.5% while it was 3.7%, 8.5%, 4.7%, and 4.9%, respectively, in Centers 1, 2, 3, and 4. Coagucheck has an acceptable level of accuracy for INR values in the range between 2.0 and 3.0. A wide variation in monitor performance was found among centers.

Autoimmune CL-rA need a plasma protein, beta 2GPI, to bind anionic PL. While beta 2GPI could be the true antigen, beta 2GPI binding to solid phase heparin did not determine its recognition by CL-rA when using patient plasmas. We tested plasmas from four patients with antiphospholipid syndrome in this study and no CL-rA binding to heparin sepharose was obtained. On the contrary, when CL-rA were first purified from the plasmas by means of a CL-octyl sepharose column, the purified material bound to the heparin sepharose column. Thus, after recognizing beta 2 GPI, CL-rA bind heparin. 'In vivo' CL-rA binding to heparin like-substances could inhibit the anti-thrombotic properties of endothelial cells.

We describe a novel method for the purification of aPL, in which pure CL is immobilized on octyl-sepharose beads by hydrophobic interaction. No lipid contamination was present in eluates, and the system could be reutilized three times without loosing extracting capacity. Four patients with antiphospholipid syndrome were studied. A marked decrease in aCL and LA activities was found in all patient plasmas after the passage through a CL-octyl-sepharose column. Both activities were recovered in eluates which contained beta 2-GP-I and IgGs. beta 2-GP-I was also present in normal plasma eluates, which showed no aCL and slight LA activity. This method represents an improvement in the purification of aPL, and could be useful in explaining the mechanism of action of antibodies that are obtained using pure phospholipid as extracting matrix.