Case Report: Resetting the Humoral Immune Response by Targeting Plasma Cells With Daratumumab in Anti-Phospholipid Syndrome.

Introduction: Monoclonal antibodies (mAb) targeting plasma cells are malignant gammopathy designed and approved therapies. In recent years, these antibodies have also been increasingly introduced for non-malignant conditions such as autoimmune-mediated diseases. The Anti-Phospholipid Syndrome (APS) is an immune-mediated disorder in which autoantibodies against phospholipid associated proteins could elicit the activation of the coagulation cascade in specific situations. Therefore, the mainstream treatment for APS patients is the use of anticoagulant therapy. However, there are refractory patients who would benefit from targeting the antibodies rather than their effects. Rituximab, a B-cell depleting mAb, and intravenous immunoglobulins (IVIG) have been used in APS patients without showing a clear beneficial effect or a significant drop in anti-phospholipid antibody (aPL) levels. Clinical case: We present our first APS case treated with daratumumab, an anti-CD38 mAb, in a 21-year-old patient with APS who presented with recurrent venous thromboembolic events despite adequate anticoagulant therapy. She tested positive for lupus anticoagulant, anti-cardiolipin IgG, anti-beta-2-glycoprotein-I IgG and anti-phosphatidylserine/prothrombin IgG and IgM. She was administered one dose weekly of daratumumab for 4 weeks. The treatment showed an adequate safety profile and was well tolerated. The patient was discharged after undergoing a clinically significant improvement. After the therapy, her levels of positive aPL declined significantly and most continued to decrease during the next three months. The patient experienced a new thrombotic episode two years after the therapy associated with poor adherence to antithrombotic therapy. Conclusions: The treatment with daratumumab showed an adequate safety profile, was well tolerated and led to a significant clinical improvement. Levels of aPL lowered on therapy and the next three months and then rose again during follow-up. Further investigation is needed to better elucidate the role and optimal timing and doses of daratumumab in treatment of refractory APS.

COVID-19 and Its Implications for Thrombosis and Anticoagulation.

Venous thromboembolism, occlusion of dialysis catheters, circuit thrombosis in extracorporeal membrane oxygenation (ECMO) devices, acute limb ischemia, and isolated strokes, all in the face of prophylactic and even therapeutic anticoagulation, are features of novel coronavirus disease 2019 (COVID-19) coagulopathy. It seems well established at this time that a COVID-19 patient deemed sick enough to be hospitalized, should receive at least prophylactic dose anticoagulation. However, should some hospitalized patients have dosage escalation to intermediate dose? Should some be considered for full-dose anticoagulation without a measurable thromboembolic event and how should that anticoagulation be monitored? Should patients receive postdischarge anticoagulation and with what medication and for how long? What thrombotic issues are related to the various medications being used to treat this coagulopathy? Is antiphospholipid antibody part of this syndrome? What is the significance of isolated ischemic stroke and limb ischemia in this disorder and how does this interface with the rest of the clinical and laboratory features of this disorder? The aims of this article are to explore these questions and interpret the available data based on the current evidence.

Association of venous thromboembolic events with skin, pulmonary and kidney involvement in ANCA-associated vasculitis: a multinational study.

OBJECTIVE: To investigate the occurrence of venous thromboembolic events (VTE) in a large cohort of patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) across the European Union, Turkey, Russia, UK and North America. METHODS: Patients with a definite diagnosis of AAV who were followed for at least 3 months and had sufficient documentation were included. Data on VTE, including either deep vein thrombosis or pulmonary embolism, were collected retrospectively from tertiary vasculitis centres. Univariate and multivariate regression models were used to estimate odds ratios (ORs) and 95% CIs. RESULTS: Over a median follow-up of 63 (interquartile range: 29, 101) months, VTE occurred in 278 (9.7%) of 2869 AAV patients with a similar frequency across different countries (from 6.3% to 13.7%), and AAV subtype [granulomatosis with polyangiitis: 9.8% (95% CI: 8.3, 11.6%); microscopic polyangiitis: 9.6% (95% CI: 7.9, 11.4%); and eosinophilic granulomatosis with polyangiitis: 9.8% (95% CI: 7.0, 13.3%)]. Most VTE (65.6%) were reported in the first-year post-diagnosis. Multiple factor logistic regression analysis adjusted for sex and age showed that skin (OR 1.71, 95% CI: 1.01, 2.92), pulmonary (OR 1.78, 95% CI: 1.04, 3.14) and kidney [eGFR 15-60 ml/min/1.73 m2, OR 2.86 (95% CI: 1.27, 6.47); eGFR <15 ml/min/1.73 m2, OR 6.71 (95% CI: 2.94, 15.33)] involvement were independent variables associated with a higher occurrence of VTE. CONCLUSION: Two-thirds of VTE occurred during the initial phase of active disease. We confirmed previous findings from smaller studies that a decrease in kidney function, skin involvement and pulmonary disease are independently associated with VTE.

Immunothrombosis and thromboinflammation in host defense and disease.

Platelets are increasingly being recognized for playing roles beyond thrombosis and hemostasis. Today we know that they mediate inflammation by direct interactions with innate immune cells or secretion of cytokines/chemokines. Here we review their interactions with neutrophils and monocytes/macrophages in infection and sepsis, stroke, myocardial infarction and venous thromboembolism. We discuss new roles for platelet surface receptors like GPVI or GPIb and also look at platelet contributions to the formation of neutrophil extracellular traps (NETs) as well as to deep vein thrombosis during infection, e.g. in COVID-19 patients.

The clinical impact of COVID-19 epidemic in the hematologic setting.

The rapid onset and worldwide spread of the COVID-19 epidemic (caused by SARS-CoV-2 coronavirus) has been associated with a profound impact in clinical practice also in the hematologic setting. First of all, given the immunosuppressive effect of many therapies that are normally administered to patients with hematological diseases, with a consequent increased risk of contracting a more severe viral infection, it has been necessary to reconsider in each individual patient the urgency and priority of the treatments foreseen by the normal standards of care. In particular, as regards allogeneic (and to a lesser extent autologous) hematopoietic cell transplantation and CAR T-cell therapy, specific recommendations have been issued by the transplant community on the criteria to be used to decide whether or not to postpone these procedures and on the clinical management of recipients and donors exposed to COVID-19. As to cytotoxic chemotherapy and other antineoplastic therapies, criteria have been proposed to decide, in the various clinical situations, which treatments were not deferrable and which instead could be postponed or replaced by less aggressive therapies. In the outpatient clinics, various organizational solutions for telemedicine have been adopted, resorting to telephone interviews and/or Information Technology, with the aim of reducing the influx of patients while maintaining an adequate control of their clinical condition. The collection of blood by the transfusion centers has been the subject of organizational measures, in order to avoid the transmission of COVID 19 while maintaining a sufficient blood collection for clinical needs. Finally, some hematologic laboratory alterations have been identified, such as thrombocytopenia, lymphopenia and coagulation abnormalities, useful for the prognostic evaluation of infected patients.

Antiphosphatidylserine/prothrombin (aPS/PT) antibodies are associated with Raynaud phenomenon and migraine in primary thrombotic antiphospholipid syndrome.

Objectives Antibodies to phosphatidylserine/prothrombin complex (aPS/PT) detectable in sera of some patients with antiphospholipid syndrome (APS) have been shown to correlate with thrombosis. However, associations of aPS/PT antibodies with APS related disorders remain unclear. Aim To evaluate whether there are any associations between aPS/PT antibodies and Raynaud phenomenon, migraine and/or valvular lesions in primary thrombotic APS (PAPS). Methods We enrolled 67 consecutive patients (56 women) with thrombotic PAPS (VTE in 80.6%), aged 46.2 ± 13.5 years. The exclusion criteria were: acute coronary syndromes or stroke within preceding 6 months, cancer, severe comorbidities and pregnancy. The IgG and IgM aPS/PT antibodies were determined by ELISA with the cut-off of 30 units. We recorded Raynaud phenomenon, migraine and valvular lesions. Results Positive IgM or/and IgG aPS/PT antibodies were observed in 29 patients (43.3%), with a higher prevalence of IgM antibodies ( n = 27, 40.3%) compared with IgG isotype ( n = 12, 17.9%, p = 0.014). aPS/PT antibodies were observed most commonly in patients with triple aPL ( n = 12, 85.7%) compared with those with double ( n = 5, 35.7%) or single aPL antibodies (n = 12, 30.8%, p = 0.03), with no association with demographics, the ANA titre, the type of thrombotic events or medications. Raynaud phenomenon, migraine and valvular lesions were observed in 15% ( n = 10), 30% ( n = 20) and 18% ( n = 12) of the patients, respectively. Raynaud phenomenon and migraine, but not valvular lesions, were markedly more frequent in PAPS patients presenting with positive aPS/PT antibodies ( n = 10, 34.5% vs. n = 0, 0%; p = 0.0001). Conclusions In PAPS patients aPS/PT antibodies are related to the occurrence of both Raynaud phenomenon and migraine.

Lymphocyte Disturbances in Primary Antiphospholipid Syndrome and Application to Venous Thromboembolism Follow-Up.

Among patients with venous thromboembolism (VTE), the persistent detection of antiphospholipid (aPL) antibodies (Ab) represents an independent high risk factor for recurrence. However, oral anticoagulation vitamin K antagonist therapy, frequently used in these patients, is problematic in assessing and/or confirming a diagnosis of primary aPL syndrome (pAPS), suggesting use of alternative strategies. For this reason, and by analogy with other autoimmune diseases, a flow cytometer approach testing peripheral T cell subsets (CD3, CD4, and CD8), B cell subsets (B1, transitional, naive, and memory), and NK cells can be proposed. As an example and to validate the concept, pAPS patients selected from the monocentric VTE case-control EDITH's cohort were selected during their follow-up. As suspected and in contrast to non-APS VTE patients, other autoimmune diseases, and controls, pAPS VTE patients displayed specific lymphocyte disturbances. Quantitative and qualitative modifications were related to total CD4+ T cell reduction, a lower CD4/CD8 ratio, and disturbance in B cell homeostasis with increased proportions of B1 cells, transitional B cells (CD24++CD38++), and naive B cells (IgD+CD27-), while memory B cells (IgD+CD27+ and IgD-CD27+) were reduced. Interestingly, the absolute number of CD4+ T cells positively correlated with IgG anti-cardiolipin Ab levels. Altogether, disturbances of T and B cell homeostasis characterized pAPS VTE patients during their follow-up. This suggests a means of profiling that could be used in addition to existing criteria to characterize them.

Anti-DFS antibodies occur more commonly in patients following unprovoked venous thromboembolism.

Introduction: It has been reported in a small group of patients that a significant percentage of patients with anti-DFS (dense fine speckled) antibodies has a history of idiopathic arterial or venous thrombosis and/or obstetric complications. To our knowledge there have been no larger studies regarding the prevalence of anti-DFS antibodies in provoked and unprovoked venous thromboembolism (VTE). Aim of the study: We investigated how common anti-DFS70 antibodies occur in patients following VTE and which factors affect their occurrence in this disease. Material and Methods: We screened 287 consecutive adult patients, aged below 60 years, with documented VTE treated for at least 3 months, and 129 age-matched healthy controls. Patients with cancer, severe comorbidities, documented autoimmune diseases, including antiphospholipid syndrome were ineligible. The anti- -DFS70 antibodies were determined based on immunofluorescence on Hep-2 cells. The specific immunofluorescence pattern, characterized by dense fine speckles distributed the nucleus, observed at serum dilution equal to or greater than 1:100, was considered as positive and was confirmed using the semiquantitative ELISA-DFS that provided results as a ratio (RU/ml) with a cut-off of 1. Results: There was no difference in the prevalence of anti-DFS70 antibodies in the VTE and control patients (n=12, 4.18% vs. n=6, 4.65%, p=0.68). Anti-DFS antibodies represented 9.16% of all positive ANA patterns (n=131) in VTE patients, which was a much lower proportion compared with 26.1% of all 23 positive ANA patterns in healthy subjects (p=0.031). The presence of anti-DFS antibodies did not correlate with demographic or clinical variables including time since last VTE event, type of anticoagulation and its quality. The prevalence of anti-DFS70 antibodies was higher in patients with ANA titer ≥1:320 compared to those with the titer < 1:320 (75% vs. 37%, p=0.01). Of importance, higher prevalence of anti-DFS antibodies was observed in patients with unprovoked VTE compared to those with provoked VTE (75% vs. 25%, p=0.01). Among the VTE patients with heritable thrombophilia, i.e. factor V Leiden or prothrombin G20210A mutations, 25.8% of subjects (n=8) had anti-DFS antibodies. Moreover, anti-DFS titer was associated with serum alpha and gamma globulin levels (r=0.47, p=0.027; and r=0.39, p=0.045, respectively), but not with inflammatory markers or D-dimer in VTE patients. Conclusions: Anti-DFS antibodies are present in <5% of VTE patients and are associated with unprovoked VTE including that related to heritable thrombophilia. It might suggest that these antibodies are involved in the pathogenesis of idiopathic VTE.

Soluble urokinase plasminogen activator receptor and incidence of venous thromboembolism.

Raised plasma levels of the soluble urokinase plasminogen activator receptor (suPAR) have been associated with increased incidence of cardiovascular diseases. Whether suPAR is associated with venous thromboembolism (VTE) is largely unknown. The purpose of the present study was to investigate the relationship between suPAR and incidence of VTE in a cohort study. suPAR was measured in 5,203 subjects (aged 46-68 years, 58 % women) from the general population, who participated in the Malmö Diet and Cancer (MDC) study between 1991 and 1994. Incident cases of VTE were identified from the Swedish patient register during a mean follow-up of 15.7 years. Of 5,203 subjects with measurements of suPAR, 239 had VTE during follow-up (127 venous thrombosis, 86 lung embolism, 26 both). Incidence of VTE was significantly higher in subjects with suPAR levels in the top quartile. Adjusted for age and sex, the HR (4th vs 1st quartile) was 1.74 (95 %CI: 1.2-2.6, p for trend=0.003). After adjustments for risk factors, the HR was 1.66 (95 %CI: 1.1-2.5, p for trend=0.016). High level of suPAR was a risk indicator for incidence of VTE in this population-based cohort study. The causal relationships between suPAR and VTE remain to be explored.

Postsurgical Inflammation as a Causative Mechanism of Venous Thromboembolism.

Surgery is associated with an increased risk of venous thromboembolic events (VTE) including deep vein thrombosis and pulmonary embolism. Although the current treatment regiments such as mechanical manipulation and administration of pharmacological prophylaxis significantly reduced the incidence of postsurgical VTE, they remain a major cause of postoperative morbidity and mortality worldwide. The pathophysiology of venous thrombosis traditionally emphasizes the series of factors that constitute Virchow triad of factors. However, inflammation can also be a part of this by giving rise to a hypercoagulable state and endothelial damage. The inflammatory response after surgery, which is initiated by a cytokine "storm" and occurs within hours of surgery, creates a prothrombotic environment that is further accentuated by several cellular processes including neutrophil extracellular traps formation, platelet activation, and the generation of tissue factor-bearing microparticles. Although such inflammatory markers are elevated in undergoing surgery, the precise mechanism by which they give rise to venous thrombosis is poorly understood. Here, we discuss the potential mechanisms linking inflammation to thrombosis, and highlight strategies that may minimize surgical inflammation and reduce the incidence of postoperative VTE.

Extracellular DNA and histones: double-edged swords in immunothrombosis.

The existence of extracellular DNA in human plasma, also known as cell-free DNA (cfDNA), was first described in the 1940s. In recent years, there has been a resurgence of interest in the functional significance of cfDNA, particularly in the context of neutrophil extracellular traps (NETs). cfDNA and histones are key components of NETs that aid in the host response to infection and inflammation. However, cfDNA and histones may also exert harmful effects by triggering coagulation, inflammation, and cell death and by impairing fibrinolysis. In this article, we will review the pathologic nature of cfDNA and histones in macrovascular and microvascular thrombosis, including venous thromboembolism, cancer, sepsis, and trauma. We will also discuss the prognostic value of cfDNA and histones in these disease states. Understanding the molecular and cellular pathways regulated by cfDNA and histones may provide novel insights to prevent pathological thrombus formation and vascular occlusion.

Epidemiology and pathophysiology of venous thromboembolism: similarities with atherothrombosis and the role of inflammation.

Venous thromboembolism (VTE) is a multifactorial disease. Major provoking factors (e. g. surgery, cancer, major trauma, and immobilisation) are identified in 50-60 % of patients, while the remaining cases are classified as unprovoked. However, minor predisposing conditions may be detectable in these patients, possibly concurring to the pathophysiology of the disease, especially when co-existing. In recent years, the role of chronic inflammatory disorders, infectious diseases and traditional cardiovascular risk factors has been extensively investigated. Inflammation, with its underlying prothrombotic state, could be the potential link between these risk factors, as well as the explanation for the reported association between arterial and venous thromboembolic events.

Anti-protein C antibodies are associated with resistance to endogenous protein C activation and a severe thrombotic phenotype in antiphospholipid syndrome.

BACKGROUND: Antiphospholipid antibodies may interfere with the anticoagulant activity of activated protein C (APC) to induce acquired APC resistance (APCr). AIMS: To investigate the frequency and characteristics of APCr by using recombinant human APC (rhAPC) and endogenous protein C activation in antiphospholipid syndrome (APS). METHODS: APCr was assessed in APS and non-APS venous thromboembolism (VTE) patients on warfarin and normal controls with rhAPC or Protac by thrombin generation. IgG anti-protein C and anti-protein S antibodies and avidity were assessed by ELISA. RESULTS: APS patients showed greater resistance to both rhAPC and Protac than non-APS patients and normal controls (median normalized endogenous thrombin potential inhibition): APS patients with rhAPC, 81.3% (95% confidence interval [CI] 75.2-88.3%; non-APS patients with rhAPC, 97.7% (95% CI 93.6-101.8%; APS patients with Protac, 66.0% (95% CI 59.5-72.6%); and non-APS patients with Protac, 80.7 (95% CI 74.2-87.2%). APS patients also had a higher frequency and higher levels of anti-protein C antibodies, with 60% (15/25) high-avidity antibodies. High-avidity anti-protein C antibodies were associated with greater APCr and with a severe thrombotic phenotype (defined as the development of recurrent VTE while patients were receiving therapeutic anticoagulation or both venous and arterial thrombosis). Twelve of 15 (80%) patients with high-avidity anti-protein C antibodies were classified as APS category I. CONCLUSION: Thrombotic APS patients showed greater APCr to both rhAPC and activation of endogenous protein C by Protac. High-avidity anti-protein C antibodies, associated with greater APCr, may provide a marker for a severe thrombotic phenotype in APS. However, in patients with category I APS, it remains to be established whether anti-protein C or anti-ß2 -glycoprotein I antibodies are responsible for APCr.

Interleukin levels and their potential association with venous thromboembolism and survival in cancer patients.

Cytokines have been found to be elevated in cancer patients and have been associated with worse prognosis in single tumour entities. We investigated the association of eight different cytokines with venous thromboembolism (VTE) and prognosis in cancer patients. The Vienna Cancer and Thrombosis Study (CATS), a prospective study, includes patients with newly diagnosed tumour or disease progression. Patients with an overt infection are excluded. Study end-points are VTE, death, loss to follow-up or study completion. Interleukin (IL) serum levels were measured using the xMAP technology developed by Luminex. Among 726 included patients, no associations between IL levels and VTE were found, with the exception of a trend for IL-1ß and IL-6 in pancreatic cancer. Elevated levels of IL-6 [as continuous variable per double increase hazard ratio (HR) = 1·07, 95% confidence interval (CI) = 1·027-1·114, P = 0·001, IL-8 (HR = 1·12, 95% CI = 1·062-1·170, P < 0·001) and IL-11 (HR = 1·37, 95% CI = 1·103-1·709, P = 0·005] were associated with worse survival. In subgroup analyses based on tumour type, colon carcinoma patients, who had higher IL-6 levels, showed a shorter survival (HR = 2·405, 95% CI = 1·252-4·618, P = 0·008). A significant association of elevated IL-10 levels with a decrease in survival (HR = 1·824, 95% CI = 1·098-3·031, P = 0·020) was seen among patients with lung cancer. No correlation between VTE and IL levels was found, but higher IL-6, IL-8 and IL-11 levels were associated with worse survival in cancer patients. Further, elevated IL-6 levels might be a prognostic marker in colorectal cancer and elevated IL-10 levels in lung cancer patients.

Autoimmune, neurological, and venous thromboembolic adverse events after immunisation of adolescent girls with quadrivalent human papillomavirus vaccine in Denmark and Sweden: cohort study.

OBJECTIVE: To assess the risk of serious adverse events after vaccination of adolescent girls with quadrivalent human papillomavirus (qHPV) vaccine. DESIGN: Register based cohort study. SETTING: Denmark and Sweden, October 2006 to December 2010. PARTICIPANTS: 997,585 girls aged 10-17, among whom 296,826 received a total of 696,420 qHPV vaccine doses. MAIN OUTCOME MEASURES: Incident hospital diagnosed autoimmune, neurological, and venous thromboembolic events (53 different outcomes) up to 180 days after each qHPV vaccine dose. Only events with at least five vaccine exposed cases were considered for further assessment. Rate ratios adjusted for age, country, calendar year, and parental country of birth, education, and socioeconomic status were estimated, comparing vaccinated and unvaccinated person time. For outcomes where the rate ratio was significantly increased, we regarded three criteria as signal strengthening: analysis based on 20 or more vaccine exposed cases (reliability), rate ratio 3.0 or more (strength), and significantly increased rate ratio in country specific analyses (consistency). We additionally assessed clustering of events in time and estimated rate ratios for a risk period that started on day 181. RESULTS: Among the 53 outcomes, at least five vaccine exposed cases occurred in 29 and these were analysed further. Whereas the rate ratios for 20 of 23 autoimmune events were not significantly increased, exposure to qHPV vaccine was significantly associated with Behcet's syndrome, Raynaud's disease, and type 1 diabetes. Each of these three outcomes fulfilled only one of three predefined signal strengthening criteria. Furthermore, the pattern of distribution in time after vaccination was random for all three and the rate ratios for these outcomes in the period from day 181 after vaccination were similar to the rate ratios in the primary risk period. The rate ratios for five neurological events were not significantly increased and there were inverse associations with epilepsy (rate ratio 0.66, 95% confidence interval 0.54 to 0.80) and paralysis (0.56, 0.35 to 0.90). There was no association between exposure to qHPV vaccine and venous thromboembolism (0.86, 0.55 to 1.36). CONCLUSIONS: This large cohort study found no evidence supporting associations between exposure to qHPV vaccine and autoimmune, neurological, and venous thromboembolic adverse events. Although associations for three autoimmune events were initially observed, on further assessment these were weak and not temporally related to vaccine exposure. Furthermore, the findings need to be interpreted considering the multiple outcomes assessed.

Thrombosis risk and survival in cancer patients with elevated C-reactive protein.

BACKGROUND: The incidence of venous thromboembolism (VTE) is increased among cancer patients. OBJECTIVE: We assessed serum levels of C-reactive protein (CRP) in order to study their prognostic significance for VTE and survival in the prospective observational Cancer and Thrombosis Study (CATS). PATIENTS AND METHODS: This study includes patients with recently diagnosed cancer or progression of disease after remission. Occurrence of VTE and information on the patients' anti-cancer-treatment are recorded. Observation ends with occurrence of objectively confirmed VTE, death or after 2 years. CRP levels were determined by an immunonephelometric method. RESULTS: We included 705 consecutive patients with solid tumors. During the observation period, VTE occurred in 43 (6.1%) patients and 413 (58.6%) died. The cumulative probability of VTE was 6.6% after 1 year. In univariate analysis, CRP (as metric variable, per double increase) was associated with VTE [hazard ratio (HR) 1.2, 95% confidence interval (CI) 1.1-1.3 P = 0.048]. However, in multivariable analysis including chemotherapy, surgery and radiotherapy, metastasis, cancer-site and sP-selectin the association with VTE (HR 1.0, 95% CI 0.9-1.2 P = 0.932) was no longer observed. CRP was clearly associated with worse survival probability with a HR of 1.3 (95% CI 1.2-1.3, P < 0.0001) in multivariable analysis. The cumulative survival after 12 months was 43% in patients with CRP above the 75th percentile (1.8 mg dL(-1) ) and 82% in those below the 75th percentile. CONCLUSIONS: In cancer patients elevated CRP was not independently associated with VTE. CRP was significantly associated with worse survival.

Solid cancer, antiphospholipid antibodies, and venous thromboembolism.

The pathogenic role of antiphospholipid antibodies (aPL) in the development of venous thromboembolism (VTE) in patients with malignancies has not been established. From May 2006 to April 2008, 258 consecutive patients with solid-organ malignancies who developed VTE (VTE+) were recruited. A group of 142 patients matched for age, sex and tumor type cancer patients without VTE (VTE-) and an age-and-sex matched group of 258 healthy subjects were also included. A second blood sample was taken in positive aPL patients at least 12 weeks later. Twenty-one (8.1%) VTE+ patients, 2 (1.4%) VTE- patients (p=0.006) and 2 (0.8%) healthy subjects (p<0.001) were positive for aPL. Persistent aPL positivity was observed in only 4 out of 15 available VTE+ patients. No differences in demographic characteristics, clinical pattern and outcome were observed in VTE+ patients according to aPL status. The low prevalence and transience of aPL positivity in patients with solid-organ malignancies with VTE argues against a pathogenic role in the development of thrombosis in this setting. The published evidence of the relationship between cancer, aPL, and thrombosis is reviewed.

Binding of anti-GRP78 autoantibodies to cell surface GRP78 increases tissue factor procoagulant activity via the release of calcium from endoplasmic reticulum stores.

The increased risk of venous thromboembolism in cancer patients has been attributed to enhanced tissue factor (TF) procoagulant activity (PCA) on the surface of cancer cells. Recent studies have shown that TF PCA can be modulated by GRP78, an endoplasmic reticulum (ER)-resident molecular chaperone. In this study, we investigated the role of cell surface GRP78 in modulating TF PCA in several human cancer cell lines. Although both GRP78 and TF are present on the cell surface of cancer cells, there was no evidence of a stable interaction between recombinant human GRP78 and TF, nor was there any effect of exogenously added recombinant GRP78 on cell surface TF PCA. Treatment of cells with the ER stress-inducing agent thapsigargin, an inhibitor of the sarco(endo)plasmic reticulum Ca(2+) pump that causes Ca(2+) efflux from ER stores, increased cytosolic [Ca(2+)] and induced TF PCA. Consistent with these findings, anti-GRP78 autoantibodies that were isolated from the serum of patients with prostate cancer and bind to a specific N-terminal epitope (Leu(98)-Leu(115)) on cell surface GRP78, caused a dose-dependent increase in cytosolic [Ca(2+)] and enhanced TF PCA. The ability to interfere with cell surface GRP78 binding, block phospholipase C activity, sequester ER Ca(2+), or prevent plasma membrane phosphatidylserine exposure resulted in a significant decrease in the TF PCA induced by anti-GRP78 autoantibodies. Taken together, these findings provide evidence that engagement of the anti-GRP78 autoantibodies with cell surface GRP78 increases TF PCA through a mechanism that involves the release of Ca(2+) from ER stores. Furthermore, blocking GRP78 signaling on the surface of cancer cells attenuates TF PCA and has the potential to reduce the risk of cancer-related venous thromboembolism.

Impact of high titre of antiphospholipid antibodies on postoperative outcome following pulmonary endarterectomy.

OBJECTIVES: Antiphospholipid (a-PL) antibodies, especially IgG isotype, have been associated with a variety of neurological manifestations related to thrombotic mechanism and reactivity against nervous tissues. Furthermore, high titre of a-PL antibodies has been also correlated to chronic thromboembolic pulmonary hypertension (CTEPH) and, therefore, is frequently reported in patients undergoing pulmonary endarterectomy (PEA). The impact of a-PL antibodies in postoperative outcome following PEA, however, has not been clearly evaluated yet. In this paper, we investigated the impact of a high a-PL IgG titre (HAPT) on postoperative outcome following PEA. METHODS: From April 1994 to October 2008, out of 204 patients undergoing PEA at our centre, 184 were prospectively screened for a-PL antibodies. According to the preoperative IgG titre, patients were divided into two groups: Group A (high a-PL antibodies titre - HAPT) with a-PL IgG titre >10 U/ml and Group B (low a-PL antibodies titre - LAPT) with a-PL IgG titre

Is obstetric antiphospholipid syndrome a primary nonthrombotic, proinflammatory, complement-mediated disorder related to antiphospholipid antibodies?

UNLABELLED: Pregnancy loss is the main obstetrical complication of the obstetric antiphospholipid syndrome. Classically, such losses have been attributed to placental thrombosis and infarcts, although in many cases there is no evidence of decidual thrombosis or placental vasculopathy, and instead inflammatory signs are present. In addition, the prevalence of systemic thrombosis is low in obstetric antiphospholipid syndrome, suggesting an alternative pathogenesis. There is evidence that antiphospholipid antibodies, mainly beta2-glycoprotein-I/anti-beta2-glycoproteina-I complexes, activate both classical and alternative complement pathways. Complement proteins may injure trophoblast cells, recruiting and activating monocytes and neutrophils. Free radicals and proteolytic enzymes could also attack trophoblastic cells, and amplification of the causal loop between tissue factor, inflammatory cells, and complement proteins could also be a factor. Overall, these diverse mechanisms may explain both inflammatory and thrombotic placental alterations. The role played by certain pro-inflammatory cytokines, mainly tumor necrosis factor-alpha, and the altered balance between angiogenic and anti-angiogenic factors remains to be clarified. In the end, obstetric antiphospholipid syndrome seems to be a clinical subset of classical APS. In these women, systemic thrombotic risk seems to be low. Current knowledge about inflammatory pathway involvement in obstetric antiphospholipid syndrome will permit us to modify the time to start heparin treatment, currently recommended to begin it as soon as possible after pregnancy confirmation. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader will be able to recall manifestations of obstetric antiphospholipid syndrome, describe nonthrombotic mechanisms that may affect obstetric outcomes in women with antiphospholipid syndrome, and predict changes in the evaluation and treatment of obstetric patients with antiphospholipid syndrome should inflammatory factors prove to be an important feature of antiphospholipid syndrome.