Markers of refractory primary immune thrombocytopenia.

Refractory immune thrombocytopenia (ITP) is a challenging disease that can be defined by refractoriness to second-line treatments. In this review, we list and comment available evidence about clinical and biological factors associated with refractoriness to splenectomy, thrombopoietin receptor agonists (TPO-RAs), rituximab and fostamatinib, as well as those associated with multirefractory ITP (active disease with failure of rituximab, TPO-RAs and splenectomy).

Complement activation negatively affects the platelet response to thrombopoietin receptor agonists in patients with immune thrombocytopenia: a prospective cohort study.

Increased platelet destruction is central in the pathogenesis of immune thrombocytopenia. However, impaired platelet production is also relevant and its significance underlies the rationale for treatment with thrombopoietin receptor agonists (TPO-RAs). Previous studies have associated enhanced complement activation with increased disease severity. Additionally, treatment refractoriness has been demonstrated to resolve by the administration of complement-targeted therapeutics in a subset of patients. The association between complement activation and the platelet response to TPO-RA therapy has previously not been investigated. In this study, blood samples from patients with immune thrombocytopenia (n = 15) were prospectively collected before and two, six and 12 weeks after the initiation of TPO-RA therapy. Plasma levels of complement degradation product C4d and soluble terminal complement complexes were assessed. Patients with significantly elevated baseline levels of terminal complement complexes exhibited more often an inadequate platelet response (p = .04), were exclusively subjected to rescue therapy with intravenous immunoglobulin (p = .02), and did not respond with a significant platelet count increase during the study period. C4d showed a significant (p = .01) ability to distinguish samples with significant terminal complement activation, implying engagement of the classical complement pathway. In conclusion, elevated levels of complement biomarkers were associated with a worse TPO-RA treatment response. Larger studies are needed to confirm these results. Biomarkers of complement activation may prove valuable as a prognostic tool to predict which patients that potentially could benefit from complement-inhibiting therapy in the future.

What is the context?Primary immune thrombocytopenia (ITP) is a potentially serious illness associated with an increased risk of bleeds. Manifestations range from confined skin bruising to life-threatening intracranial hemorrhages.It is an acquired immune disorder characterized by increased destruction and impaired production of platelets.Treatments aim at suppressing the destruction and supporting the production of platelets.Thrombopoietin receptor agonists (TPO-RA) are medically approved platelet growth factors that contribute to the generation of new platelets.The complement system is an evolutionary preserved part of innate immunity.Previous studies have indicated that complement activation may be an important contributor to disease and that the administration of complement-inhibiting therapy improves the platelet count in a subset of patients with primary ITP.What is new? The potential association between complement activation and a poor platelet response to TPO-RA therapy in primary ITP has not been previously studied.In fifteen patients with primary ITP starting TPO-RA therapy, we prospectively followed the platelet response and levels of complement biomarkers for 12 weeks.We showed that patients with high levels of complement biomarkers exhibited a worse treatment response during the study period.What is the impact?Our results suggest that levels of complement biomarkers may be valuable to predict which patients with treatment-refractory ITP that potentially could benefit from complement-inhibiting therapy in the futureLarger studies are needed to confirm our results.

Cytokine and Gene Expression Profiling in Patients with HFE-Associated Hereditary Hemochromatosis according to Genetic Profile.

BACKGROUND: Hemochromatosis gene (HFE)-associated hereditary hemochromatosis (HH) is characterized by downregulation of hepcidin synthesis, leading to increased intestinal iron absorption. OBJECTIVES: The objectives were to characterize and elucidate a possible association between gene expression profile, hepcidin levels, disease severity, and markers of inflammation in HFE-associated HH patients. METHODS: Thirty-nine HFE-associated HH patients were recruited and assigned to 2 groups according to genetic profile: C282Y homozygotes in 1 group and patients with H63D, as homozygote or in combination with C282Y, in the other group. Eleven healthy first-time blood donors were recruited as controls. Gene expression was characterized from peripheral blood cells, and inflammatory cytokines and hepcidin-25 isoform were quantified in serum. Biochemical disease characteristics were recorded. RESULTS: Elevated levels of interleukin 8 were observed in a significant higher proportion of patients than controls. In addition, compared to controls, gene expression of ζ-globin was significantly increased among C282Y homozygote patients, while gene expression of matrix metalloproteinase 8, and other neutrophil-secreted proteins, was significantly upregulated in patients with H63D. CONCLUSION: Different disease signatures may characterize HH patients according to their HFE genetic profile. Studies on larger populations, including analyses at protein level, are necessary to confirm these findings.

Increased microvesicle-associated thrombin generation in patients with immune thrombocytopenia after initiation of thrombopoietin receptor agonists.

Immune thrombocytopenia (ITP) patients have thrombocytopenia and increased bleeding risk, but, conversely, they also have increased thrombotic risk which appears to be exacerbated by thrombopoietin-receptor agonist (TPO-RA)-treatment. Microvesicles (MVs) released from activated/apoptotic cells are prothrombotic due to exposure of phosphatidylserine (PS) and tissue factor (TF). MVs are increased in ITP patients, but their prothrombotic effect, before and during treatment with TPO-RAs, is unclear.We studied the effect of TPO-RAs on the procoagulant activity of MVs in 11 ITP patients, before, and two and six weeks after initiation of treatment, and in 15 healthy controls. MV-associated PS-activity, TF-activity and the capacity of isolated MVs and plasma to generate thrombin in a phospholipid-dependent manner were measured.Before treatment with TPO-RAs, prothrombotic markers in ITP patients were comparable to levels found in healthy controls. After both two and six weeks of TPO-RA-treatment, ITP patients had higher MV-associated PS-activity and phospholipid-dependent thrombin generation in plasma than controls. In addition, ITP patients had increased phospholipid-dependent MV-associated thrombin generation two weeks after initiation of TPO-RA-treatment compared with controls and pre-treatment levels. MV-associated TF-activity was low in controls and in ITP patients before and after initiation of TPO-RA-treatment.In conclusion, TPO-RAs increase phospholipid-dependent MV-associated thrombin generation in ITP patients. This could contribute to or exacerbate a pre-existing hypercoagulable state. Phospholipid-dependent thrombin generation generated by isolated MVs, or measured directly in plasma, may be potential tools that could help in the risk-assessment of future thromboembolic events in ITP patients, both before and after initiation of TPO-RA-treatment.

Circulating microRNAs in patients with immune thrombocytopenia before and after treatment with thrombopoietin-receptor agonists.

MicroRNAs (miRNAs) are small non-coding RNAs involved in the regulation of gene expression. Dysregulated expression of several miRNAs has been found in primary immune thrombocytopenia (ITP) suggesting that miRNAs are likely involved in the pathogenesis of ITP. We aimed to explore the differential expression of miRNAs in patients with ITP before and after starting treatment with thrombopoietin-receptor agonists (TPO-RAs) to clarify their roles in the pathophysiology of ITP, and as potential diagnostic and prognostic markers of this disorder.We performed a profiling study where 179 miRNAs were analyzed in eight ITP patients before and during treatment with TPO-RAs and in eight controls using miRNA PCR panel; 81 miRNAs were differentially expressed in ITP patients compared to controls, and 14 miRNAs showed significant changes during TPO-RA-treatment. Ten miRNAs were selected for validation that was performed in 23 patients and 22 controls using droplet digital PCR. Three miRNAs were found to be differentially expressed in ITP patients before TPO-RA-treatment compared to controls: miR-199a-5p was down-regulated (p = 0.0001), miR-33a-5p (p = 0.0002) and miR-195-5p (p = 0.035) were up-regulated. Treatment with TPO-RAs resulted in changes in six miRNAs including miR-199a-5p (p = 0.001), miR-33a-5p (p = 0.003), miR-382-5p (p = 0.004), miR-92b-3p (p = 0.005), miR-26a-5p (p = 0.008) and miR-221-3p (p = 0.023); while miR-195-5p remained unchanged and significantly higher than in controls, despite the increase in the platelet count, which may indicate its possible role in the pathophysiology of ITP. Regression analysis revealed that pre-treatment levels of miR-199a-5p and miR-221-3p could help to predict platelet response to TPO-RA-treatment. ROC curve analysis showed that the combination of miR-199a-5p and miR-33a-5p could distinguish patients with ITP from controls with AUC of 0.93.This study identifies a number of differentially expressed miRNAs in ITP patients before and after initiation of TPO-RAs with potential roles in the pathophysiology, as well as with a possible utility as diagnostic and prognostic biomarkers. These interesting findings deserve further exploration and validation in future studies.

Platelet activation and neutrophil extracellular trap (NET) formation in immune thrombocytopenia: is there an association?

No biological predictors for the increased risk of thrombosis in patients with immune thrombocytopenia (ITP) have been identified. The aim of the study was to investigate platelet and neutrophil activation as well neutrophil extracellular trap (NET) formation in 63 ITP patients and 30 healthy volunteers. Platelet and neutrophil activation was assessed during steady state using flow cytometry analysis, and NETs were evaluated by quantitation of cell free DNA (cfDNA), and citrullinated histone-3-DNA (CitH3-DNA). Patient platelets and neutrophils showed increased CD62 and CD11b expression compared to controls (p = .038, and p = .022, respectively). In patients, platelet activation inversely correlated with platelet count and platelet size (p < .001), and positively correlated with neutrophil degranulation (p = .024). More NET formation, both CitH3-DNA (p = .025) and cfDNA(p < .001), were present in ITP patients compared to controls. CitH3-DNA inversely correlated with CD62 expression on platelets (p = .042), but higher levels of cfDNA were observed in individuals with classical cardiovascular risk factors for thrombosis, and in those with a previous history of thrombotic events. In this disease, the increased platelet activation and plasma NET levels seem to be separable processes that associate (either positively or inversely in the case of CitH3-DNA or platelet degranulation, respectively) to platelet mass.

Effect of thrombopoietin receptor agonists on markers of coagulation and P-selectin in patients with immune thrombocytopenia.

Thrombopoietin-receptor-agonists (TPO-RA) are effective treatments of immune thrombocytopenia (ITP). Previous long-term TPO-RA clinical trials have shown that thrombotic events occurred in 6% of TPO-RA-treated ITP patients. To explore the increased risk of thrombosis, the effects of TPO-RA on markers of coagulation and P-selectin were studied. The study comprised two ITP cohorts and controls. Cohort 1 included 26 patients with sequential samples acquired before and during treatment with TPO-RA. Cohort 2 included a single sample in 18 patients on TPO-RA for more than one year. Thrombin generation (endogenous thrombin potential (ETP)) prothrombin fragments 1 + 2 (F1+2), D-dimer, and plasminogen-activator-inhibitor-1 (PAI-1) were measured as well as soluble P-selectin (sP-selectin). Sequential expression of encoding genes for P-selectin (SELP) and PAI-1 (SERPINE1) was determined in four patients in cohort 1. Significantly higher levels of F1+2, D-dimer, and PAI-1 were found in ITP patients before TPO-RA treatment and in patients on long-term TPO-RA treatment than in controls. Pre-treatment levels of sP-selectin did not differ from controls. Analysis of longitudinal trends showed an increase in platelet count, sP-selectin, and PAI-1 after initiation of TPO-RA, followed by gradual decline. Platelet count and sP-selectin remained at higher levels throughout the study, whereas PAI-1 did not. Levels of other studied parameters did not show significant changes after initiation of treatment. Expression of SELP was up-regulated after initiation of TPO-RA, while the expression of SERPINE1 showed no significant changes. In conclusion, elevated pre-treatment levels of F1+2, D-dimer and PAI-1 are compatible with ITP being an intrinsically pro-thrombotic condition. After TPO-RA treatment, there were no significant changes in markers of coagulation activation or fibrinolysis, except for an initial increase in PAI-1 and a significant increase in sP-selectin both of which may contribute to increased thrombotic risk associated with TPO-RA treatment in ITP.

Predictors of Pregnancy Outcomes in Patients With Lupus: A Cohort Study.

BACKGROUND: Because systemic lupus erythematosus (SLE) affects women of reproductive age, pregnancy is a major concern. OBJECTIVE: To identify predictors of adverse pregnancy outcomes (APOs) in patients with inactive or stable active SLE. DESIGN: Prospective cohort. SETTING: Multicenter. PATIENTS: 385 patients (49% non-Hispanic white; 31% with prior nephritis) with SLE in the PROMISSE (Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Antibody Syndrome and Systemic Lupus Erythematosus) study. Exclusion criteria were urinary protein-creatinine ratio greater than 1000 mg/g, creatinine level greater than 1.2 mg/dL, prednisone use greater than 20 mg/d, and multifetal pregnancy. MEASUREMENTS: APOs included fetal or neonatal death; birth before 36 weeks due to placental insufficiency, hypertension, or preeclampsia; and small-for-gestational-age (SGA) neonate (birthweight below the fifth percentile). Disease activity was assessed with the Systemic Lupus Erythematosus Pregnancy Disease Activity Index and the Physician's Global Assessment (PGA). RESULTS: APOs occurred in 19.0% (95% CI, 15.2% to 23.2%) of pregnancies; fetal death occurred in 4%, neonatal death occurred in 1%, preterm delivery occurred in 9%, and SGA neonate occurred in 10%. Severe flares in the second and third trimesters occurred in 2.5% and 3.0%, respectively. Baseline predictors of APOs included presence of lupus anticoagulant (LAC) (odds ratio [OR], 8.32 [CI, 3.59 to 19.26]), antihypertensive use (OR, 7.05 [CI, 3.05 to 16.31]), PGA score greater than 1 (OR, 4.02 [CI, 1.84 to 8.82]), and low platelet count (OR, 1.33 [CI, 1.09 to 1.63] per decrease of 50 × 109 cells/L). Non-Hispanic white race was protective (OR, 0.45 [CI, 0.24 to 0.84]). Maternal flares, higher disease activity, and smaller increases in C3 level later in pregnancy also predicted APOs. Among women without baseline risk factors, the APO rate was 7.8%. For those who either were LAC-positive or were LAC-negative but nonwhite or Hispanic and using antihypertensives, the APO rate was 58.0% and fetal or neonatal mortality was 22.0%. LIMITATION: Patients with high disease activity were excluded. CONCLUSION: In pregnant patients with inactive or stable mild/moderate SLE, severe flares are infrequent and, absent specific risk factors, outcomes are favorable. PRIMARY FUNDING SOURCE: National Institutes of Health.

Prevalence of pulmonary hypertension in an unselected, mixed connective tissue disease cohort: results of a nationwide, Norwegian cross-sectional multicentre study and review of current literature.

OBJECTIVES: The aim of this study was to assess the overall prevalence of pulmonary hypertension (PH) in an unselected MCTD cohort and review the current knowledge with a systematic database search. METHODS: A nationwide multicentre cohort of 147 adult MCTD patients were initially screened for PH by echocardiography, high-resolution computed tomography (HRCT), pulmonary function tests and N-terminal pro-brain natriuretic peptide (NT-proBNP) and then followed up for a mean of 5.6 years. Right-sided heart catheterization was performed when estimated pulmonary artery systolic pressure was >40 mmHg on echocardiography. PH was diagnosed according to the 2009 European Society of Cardiology and European Respiratory Society guidelines. RESULTS: At inclusion, 2.0% (3/147) had established PH. Two additional PH patients were identified during follow-up, giving a total PH frequency in the cohort of 3.4% (5/147). All five had elevated serum NT-proBNP. Two had isolated pulmonary arterial hypertension (PAH) and three PH associated with interstitial lung disease (PH-ILD). Three PH patients died during follow-up. Nine other patients in the cohort also died, but none of them had echocardiographic signs of PH prior to death. CONCLUSION: The data from the current unselected MCTD cohort suggest that the prevalence of PH is much lower than expected from previous studies but confirm the seriousness of the disease complication.

Evaluation of OneTouch Verio(®), a new blood glucose self-monitoring system for patients with diabetes.

INTRODUCTION: Self-monitoring of blood glucose (SMBG) is important in diabetes management. Reliable and user-friendly instruments are essential. OneTouch Verio(®) is a new blood glucose concentration-measuring system designed to be used by patients with diabetes and healthcare professionals. The objective of the present study was to evaluate the analytical performance of the OneTouch Verio(®). METHOD: The OneTouch Verio(®) was evaluated by the Scandinavian evaluation of laboratory equipment for primary healthcare (SKUP) according to a protocol based on ISO 15197 and the American Diabetes Association (ADA) quality goals. Blood samples were collected and measured on the OneTouch Verio(®) by laboratory personnel and patients with diabetes (n = 91, randomized into groups receiving personal training or mail instructions for the OneTouch Verio(®) system). Results were compared to a validated routine method, imprecision and bias were calculated. User-friendliness was evaluated with a questionnaire. RESULTS: Quality specifications for blood glucose concentration monitoring systems according to ISO 15197 were fulfilled. The mean coefficients of variation (CV%) of repeatability was 3.4% when tested by laboratory personnel and within the goal of imprecision suggested by ADA. Mean CV% of repeatability for patient self-monitoring was 5.0% and 5.1% in the training- and the mail group, respectively. Total error was 6.4-10.0%. The OneTouch Verio(®) showed no hematocrit interference or variation between strip lots. CONCLUSION: The OneTouch Verio(®) displayed sufficient analytical quality and satisfactory user-friendliness. It is suitable for point-of-care testing of blood glucose concentration when handled by patients and healthcare professionals.

SARS-CoV-2 vaccines are not associated with hypercoagulability in apparently healthy people.

Background: SARS-CoV-2 adenoviral vector DNA vaccines have been linked to the rare but serious thrombotic postvaccine complication vaccine-induced immune thrombotic thrombocytopenia. This has raised concerns regarding the possibility of increased thrombotic risk after any SARS-CoV-2 vaccines. Objectives: To investigate whether SARS-CoV-2 vaccines cause coagulation activation leading to a hypercoagulable state. Methods: This observational study included 567 health care personnel; 521 were recruited after the first dose of adenoviral vector ChAdOx1-S (Vaxzevria, AstraZeneca) vaccine and 46 were recruited prospectively before vaccination with a messenger RNA (mRNA) vaccine, either Spikevax (Moderna, n = 38) or Comirnaty (Pfizer-BioNTech, n = 8). In the mRNA group, samples were acquired before and 1 to 2 weeks after vaccination. In addition to the prevaccination samples, 56 unvaccinated blood donors were recruited as controls (total n = 102). Thrombin generation, D-dimer levels, and free tissue factor pathway inhibitor (TFPI) levels were analyzed. Results: No participant experienced thrombosis, vaccine-induced immune thrombotic thrombocytopenia, or thrombocytopenia (platelet count <100 × 109/L) 1 week to 1 month postvaccination. There was no increase in thrombin generation, D-dimer level, or TFPI level in the ChAdOx1-S vaccine group compared with controls or after the mRNA vaccines compared with baseline values. Eleven of 513 (2.1%) participants vaccinated with ChAdOx1-S had anti-PF4/polyanion antibodies without a concomitant increase in thrombin generation. Conclusion: In this study, SARS-CoV-2 vaccines were not associated with thrombosis, thrombocytopenia, increased thrombin generation, D-dimer levels, or TFPI levels compared with baseline or unvaccinated controls. These findings argue against the subclinical activation of coagulation post-COVID-19 vaccination.

Prevalence and severity of interstitial lung disease in mixed connective tissue disease: a nationwide, cross-sectional study.

BACKGROUND: Mixed connective tissue disease (MCTD) is an immune-mediated, systemic disorder of unknown cause. OBJECTIVE: To assess the prevalence, pattern and severity of interstitial lung disease (ILD) in a cross-sectional study of the nationwide, Norwegian MCTD cohort. METHODS: 126 patients with MCTD were systematically examined for ILD by high-resolution CT (HRCT), pulmonary function tests (PFT), 6 min walk test (6MWT) and by the New York Heart Association (NYHA) functional classification of dyspnoea. The extent and type of HRCT lung abnormalities were scored according to the CT criteria of ILD recommended by the Fleischner Society. RESULTS: All 126 patients were Caucasian, 75% women. At the time of the cross-sectional ILD study, the patients had a mean disease duration of 9.0 years. 52% of the patients had abnormal HRCT findings, most commonly reticular patterns consistent with lung fibrosis (35%). Lung fibrosis was quantified as minor in 7%, moderate in 9% and severe in 19% of the patients. Fibrosis was uniformly concentrated in the lower parts of the lungs and was not associated with smoking. Patients with severe lung fibrosis had lower PFT values, shorter 6MWT and a higher mean NYHA functional class. After a mean 4.2 years' follow-up, overall mortality was 7.9%. Mortality in patients with normal HRCT was 3.3%, as compared with 20.8% in patients with severe lung fibrosis (p<0.01). CONCLUSIONS: Severe lung fibrosis is common in MCTD, has an impact on pulmonary function and overall physical capacity and is associated with increased mortality.

The effect of rivaroxaban on the diagnostic value of D-dimer in patients with suspected deep vein thrombosis.

INTRODUCTION: Empiric anticoagulation therapy is often used in patients with suspected deep vein thrombosis (DVT) to avoid complications if the workup is delayed. Studies have shown the safety of administering direct oral anticoagulants (DOACs) and low molecular weight heparin in patients with suspected DVT. However, the impact of empiric DOACs on D-dimer levels in patients with suspected DVT is not well established. Therefore, this study aimed to determine the effect of empiric rivaroxaban on the diagnostic performance of D-dimer. MATERIALS AND METHODS: D-dimer was measured before and after the administration of one to two tablets of rivaroxaban in 418 patients referred with suspected DVT to the Emergency Department at Østfold Hospital, Norway. To determine whether the effect of rivaroxaban significantly impacted D-dimer results, we calculated the diagnostic performance of the test before and after patients had taken rivaroxaban. All patients with negative workup were followed up at 90 days. RESULTS: Two hundred eighty-six (68.4 %) of the 418 included patients had lower D-dimer results after taking rivaroxaban. Median D-dimer values decreased from 1.0 mg/L (IQR: 0.7-2.2) to 0.9 mg/L (IQR: 0.6-2.0). Thirty-six patients (8.9 %) with positive D-dimer (≥ 0.5 mg/L fibrinogen-equivalent units) before taking rivaroxaban had negative D-dimer values after rivaroxaban intake. Of these, two had DVT diagnosed by compression ultrasonography. The sensitivity of D-dimer decreased from 99.0 % (95 % CI: 94.6-99.8) to 97.0 % (95 % CI: 91.6-99.0). CONCLUSIONS: Rivaroxaban administered before measuring D-dimer may reduce the sensitivity and increase false negative results of the test. Based on these results, we recommend performing D-dimer before the administration of rivaroxaban.

Thromboembolic complications during and after hospitalization for COVID-19: Incidence, risk factors and thromboprophylaxis.

Introduction: The incidence of thromboembolism during COVID-19 and the use of thromboprophylaxis vary greatly between studies. Only a few studies have investigated the rate of thromboembolism post-discharge. This study determined the 90-day incidence of venous and arterial thromboembolic complications, risk factors for venous thromboembolic events and characterized the use of thromboprophylaxis during and after hospitalization. Materials and methods: We retrospectively reviewed medical records for adult patients hospitalized for >24 h for COVID-19 before May 15, 2020, in ten Norwegian hospitals. We extracted data on demographics, thromboembolic complications, thromboembolic risk factors, and the use of thromboprophylaxis. Cox proportional hazards regression was used to determine risk factors for VTE. Results: 550 patients were included. The 90-day incidence of arterial and venous thromboembolism in hospitalized patients was 6.9% (95% CI: 5.1-9.3) overall and 13.8% in the ICU. Male sex (hazard ratio (HR) 7.44, 95% CI 1.73-32.02, p = 0.007) and previous VTE (HR 6.11, 95% CI: 1.74-21.39, p = 0.005) were associated with risk of VTE in multivariable analysis. Thromboprophylaxis was started in 334 patients (61%) with a median duration of 7 days (25th-75th percentile 3-13); in the VTE population 10/23 (43%) started thromboprophylaxis prior to diagnosis. After discharge 20/223 patients received extended thromboprophylaxis and 2/223 (0.7%, 95% CI: 0.3-1.9) had a thromboembolism. Conclusions: The 90-day incidence of thromboembolism in COVID-19 patients was 7%, but <1% after discharge. Risk factors were male sex and previous VTE. Most patients received thromboprophylaxis during hospitalization, but only <10% after discharge.

ß-Amyloid in Cerebrospinal Fluid: How to Keep It Floating (Not Sticking) by Standardization of Preanalytic Processes and Collection Tubes.

BACKGROUND: Phosphorylated tau (pTau), total tau (tTau), and ß-amyloid (Aß) are established cerebrospinal fluid (CSF) biomarkers used to help diagnose Alzheimer disease. Preanalytic workups of CSF samples lack harmonization, making interlaboratory comparison of these biomarkers challenging. The Aß adsorbs to sample tubes, yielding underestimated concentrations, and may result in false Alzheimer disease diagnosis. Our primary aim was to compare Aß recovery across multiple polypropylene tubes and to test the stability of tTau, pTau, and Aß in the best performing tube. METHODS: Eight polypropylene tubes were tested using 3 CSF pools with Aß concentrations <500, 500-1000, and >1000 ng/L. All samples were analyzed in duplicate. Tubes were cut open to assess their different infrared adsorption spectra. Freshly drawn CSF from 14 patients was distributed into 4 Sarstedt 5-mL (no. 63.504.027; Sar5CSF) tubes, left at room temperature for up to 7 days, and analyzed for pTau, tTau, and Aß by ELISA. RESULTS: Two Sarstedt 5-mL tubes and a Sarstedt 10-mL (Sar10CSF) tube showed significantly higher Aß recovery at all 3 concentrations compared with the 5 other tubes. The infrared adsorption spectra of Sar10CSF and Sar5CSF tubes were practically identical, unlike the other tubes. No significant loss of pTau, tTau, and Aß was observed in CSF left at room temperature for up to 7 days (P > 0.05). CONCLUSIONS: Recovery of Aß from Sar5CSF tubes is equivalent to Aß recovery from Sar10CSF tubes. Levels of pTau, tTau, and Aß were stable for at least 7 days at room temperature but not at 37 °C.

Markers of endothelial cell activation and neutrophil extracellular traps are elevated in immune thrombocytopenia but are not enhanced by thrombopoietin receptor agonists.

INTRODUCTION: Patients with immune thrombocytopenia (ITP) are at increased risk of thrombosis, which seems to be further enhanced by treatment with thrombopoietin-receptor-agonists (TPO-RAs). The underlying mechanisms of thrombosis in ITP are not fully understood. Endothelial cell activation and neutrophil extracellular traps (NETs) play important roles in thrombosis, however, their roles in ITP itself, or in TPO-RA-treatment, have not yet been fully explored. We aimed to investigate whether endothelial cell activation and NETs are involved in the hypercoagulable state of ITP, and whether TPO-RA-treatment enhances endothelial cell activation and NET formation. MATERIAL AND METHODS: We measured markers of endothelial cell activation including intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1) and thrombomodulin in 21 ITP patients, and E-selectin in 18 ITP patients. Markers of NET formation, citrullinated histone H3-DNA (H3Cit-DNA) and cell-free DNA (cfDNA), were measured in 15 ITP patients. All markers were measured before, and 2 and 6 weeks after initiation of TPO-RA-treatment in ITP patients, and in matched controls. RESULTS: Higher levels of ICAM-1, thrombomodulin, and H3Cit-DNA were found in ITP patients, both before and after TPO-RA-treatment, compared with controls. No differences were found for VCAM-1, E-selectin or cfDNA. TPO-RA-treatment did not further increase markers of endothelial cell activation or NET formation. CONCLUSIONS: This study showed that ITP patients have increased endothelial cell activation and NET formation, both of which may contribute to the intrinsic hypercoagulable state of ITP. TPO-RA-treatment, however, did not further increase endothelial cell activation or NET formation indicating that other drug-associated prothrombotic mechanisms are involved.