scholarly journals Delayed Plasma Clot Lysis in Adult Patients with Primary Immune Thrombocytopenia (ITP)

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3162-3162
Author(s):  
Theresa Schramm ◽  
Jennifer Machacek ◽  
Michael Fillitz ◽  
Barbara Dixer ◽  
Peter Quehenberger ◽  
...  
Keyword(s):  
Research Funding ◽  
Immune Thrombocytopenia ◽  
Clot Lysis ◽  
Lag Phase ◽  
Healthy Controls ◽  
Plasma Clot ◽  
Significant Difference ◽  
Primary Immune Thrombocytopenia ◽  
Pai 1 ◽  
Bleeding Severity

Abstract Introduction: Primary immune thrombocytopenia (ITP) is an orphan disease characterized by very low platelet counts. Patients have heterogeneous bleeding phenotypes, which are not only determined by platelet counts, also a paradoxically increased thrombotic risk has been observed. Aim: To investigate, whether the fibrinolysis inhibitors plasminogen activator inhibitor-1 (PAI-1) and α2-antiplasmin are associated with impaired plasma clot lysis in primary ITP patients in comparison to non-immunologic thrombocytopenic controls (TPC) and healthy controls (HC). Furthermore, associations with bleeding severity and previous thrombotic events were investigated. Methods: Patients from the Vienna ITP biobank (EC 1843/2016), a multi-centric study including adult patients with primary ITP were investigated and compared to age- and sex-matched control groups: TPC with thrombocytopenia after chemotherapy and HC. Informed consent was obtained from all individuals before study inclusion. A clot formation and lysis assay (CLA) was performed according to the recommendations of the ISTH SSC. Platelet poor plasma samples were measured in duplicates for each patient and control. PAI-1 (PAI-1 Actibind ELISA, Technoclone, Vienna, Austria) and α2-antiplasmin by the chromogenic STA Stachrom antiplasmin assay (Diagnostic Stago, Asnieres, France) were measured. Bleeding severity was measured using the ITP-specific ITP-ISTH BAT (Rodeghiero et al. 2013). Results: In total, 37 primary ITP patients, 18 TPC and 156 healthy controls were analyzed (Table 1). Primary ITP patients had a higher BMI than HC. Bleeding severity was higher and more ITP patients had a thrombosis history compared to HC, whereas there was no difference in comparison to TPC. PAI-1 activity was highest in ITP patients, with a statistically significant difference in comparison to HC. α2-antiplasmin activity was higher in ITP patients than in TPC, whereas there was no difference in comparison to HC. After adjustment for sex, age, BMI and fibrinogen, primary ITP patients had a reduced clot formation rate (V max) and significantly delayed plasma clot lysis compared to TPC and HC (Table 2). Also, the lag phase and time to peak absorbance (TTP) were prolonged with a significant difference in comparison to HC. To investigate outliers of PAI-1 and α2-antiplasmin, we calculated cut-offs at the 75 th percentile of healthy controls (PAI-1: ≥ 3.1 U/mL, α2-antiplasmin: ≥ 107.0 %). 14 (37.8 %) ITP patients had PAI-1 levels and 10 (27.0 %) ITP patients had α2-antiplasmin activity above the cut-off. ITP patients with high PAI-1 levels had mildly delayed clot lysis in comparison to those below with a significantly lower maximal lysis rate (mLR). ITP patients with α2-antiplasmin activity above the cut-off had a significantly shorter lag phase, faster V max and shorter TTP than patients below the cut-off, whereas there was no difference in clot lysis. No differences between ITP patients above or below the respective cut-offs of PAI-1 and α2-antiplasmin regarding their bleeding severity and thrombosis incidence were observed (Table 3). Conclusion: Primary ITP patients have a tendency towards increased PAI-1 activity, which is associated with considerably delayed plasma clot lysis. Albeit an association with the bleeding score could not be identified, this impaired lysis could be seen as a counter-regulation and at least contribute to the relatively mild bleeding tendency in patients with ITP. Figure 1 Figure 1. Disclosures Pabinger: CSL Behring: Consultancy, Honoraria, Research Funding; NovoNordisk: Consultancy, Research Funding; Bayer: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Daiichi Sanchyo: Consultancy, Honoraria; Alexion: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria.

scholarly journals Platelet Apoptosis and PAI-1 Content Are Involved in the Procoagulant Profile of Immune Thrombocytopenia Patients Responders to Agonists of Thrombopoietin Receptor.

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3738-3738
Author(s):  
Raul Justo Sanz ◽  
Elena Monzón Manzano ◽  
Ihosvany Fernandez-Bello ◽  
Teresa Álvarez-Roman ◽  
Mónica Martín ◽  
...  
Keyword(s):  
Research Funding ◽  
Immune Thrombocytopenia ◽  
Alpha Angle ◽  
Clot Formation ◽  
Clot Lysis ◽  
Control Group ◽  
Healthy Controls ◽  
Prothrombinase Complex ◽  
Thrombopoietin Receptor ◽  
Pai 1

Abstract Background: The treatment goal for patients with immune thrombocytopenia (ITP) is to raise platelet counts to levels that minimize or stop bleeding. Thrombopoietin receptor agonists (TPO-RAs) have been successfully and extensively employed as second-line therapy for ITP. TPO-RAs, however, have a small but significant increase in the risk of thrombosis. Aim: The aim of this study was to elucidate the mechanisms involved in the procoagulant effect of TPO-RAs. Methods: This is a prospective, observational and transversal study. Eighty-two patients with chronic primary ITP, 40 without treatment for at least six months (UT-ITP) and 42 responders to TPO-RA therapy (64.3% with eltrombopag and 35.7 % with romiplostim) were recruited. One hundred and twelve healthy participants were also included. ROTEM® (naTEM test: only recalcification) was performed on platelet rich plasma adjusted to a platelet count of 25 x 109/L. Clotting time (CT, time from start of measurement until 2 mm of amplitude [in seconds], alpha angle, which reflects the rate of fibrin polymerisation (tangent to the curve at 2 mm amplitude [in degrees]), maximum clot firmness, which reflects the maximum tensile strength of the thrombus (MCF, [in mm]) and LI60, which describes the percentage of maximum clot strength present at 60 min (in %), were recorded. Surface exposure of phosphatidylserine (PS), active caspase-3, -8 or -9 and prothrombinase complex binding to platelets were assessed by flow cytometry. Plasma and platelet levels of PAI-1 were determined by ELISA (eBioscience Ltd., Hatfield, United Kingdom). The effect of TPO and romiplostim on PAI-1 content of MEG-01 cells was evaluated by Western blot. Three MEG-01 cell cultures were initiated simultaneously: control without drugs and treated with either TPO (100 ng/mL) or romiplostim (53 μg/mL). Samples were collected at the start and after 24, 48 and 72 hours to determine the PAI-1 content. The statistical analysis was performed using SPSS 9.0 software (SPSS Inc., Chicago, Illinois, USA). Results: The ROTEM® studies showed significant differences in the dynamics of clot formation when comparing the control with ITP samples. There was a delay in clot formation in the UT-ITP group, as observed by a prolonged CT [expressed as median (p25-p75): control: 516 (490- 633) s; UT-ITP: 938 (914-1348) s, p<0.001], and a diminished alpha angle (mean±SD; control: 61.7±5.6 degrees; UT-ITP: 49.2±7.3 degrees, p<0.05). Nevertheless, samples from patients with UT-ITP reached the same MCF as those from healthy controls (control: 45.3±2.4 mm; UT-ITP: 46.9±3.7 mm). On the other hand, patients with ITP undergoing TPO-RA therapy presented an initial clot formation similar to that of the control group [expressed as median (p25-p75): CT, 672 (598-928) s; alpha angle, 55.8±5.8 degrees] but achieved a higher MCF (53.1±4.5 mm, p<0.05) and a reduced clot lysis after 60 min (control: 91.8±4.0%; UT-ITP: 93.7±4.0%, TPO-RA ITP: 97.6±1.7, p<0.05). Higher values of MCF observed with platelets from ITP patients treated with TPO-RAs might be a consequence of their augmented apoptosis signs: platelets from this group exposed more PS than controls and this situation was accompanied by an increased activity of caspases-3,7, -8 and -9 (Figure 1 A and B). Moreover, platelets from ITP patients on treatment with TPO-RAs bound more prothrombinase complex than platelets from UT-ITP patients and healthy controls (Figure 1 C). Reduced clot lysis observed in ITP patients treated with TPO-RA was due, at least in part, to increased plasma and platelet levels of PAI-1 (Table 1). Increase in platelet content of PAI-1 might be the result of the effect of TPO-RAs during megakaryopoiesis since treatments of MEG-01 cells with TPO or romiplostim induced a 3-fold increase in their endogenous PAI-1 content after an incubation period of 48 hs. Conclusion: The patients with ITP undergoing TPO-RAs therapy presented a procoagulant profile due to the formation of a more fibrinolysis-resistant clot because of increased platelet and plasma PAI-1 levels. Moreover, platelets from this group of patients showed more signs of apoptosis that causes a higher exposure of PS and, consequently, a larger surface for the binding of the prothrombinase complex. Work supported by grant from FIS-FEDER PI15/01457. NB holds a Miguel Servet II (FIS-FEDER CP14/00024). Disclosures Álvarez-Roman: SOBI: Consultancy; NovoNordisk: Consultancy; Shire: Consultancy. Jimenez-Yuste:Grifols: Consultancy, Research Funding; Octapharma: Consultancy, Research Funding; CSL Behring: Consultancy; Bayer: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Shire: Consultancy, Research Funding; Sobi: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; NovoNordisk: Consultancy, Research Funding. Butta:FIS-Fondos FEDER: Research Funding.

scholarly journals Effects of Rituximab and Dexamethasone on Regulatory and Pro-Inflammatory B-Cell Subsets in Patients with Primary Immune Thrombocytopenia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1378-1378
Author(s):  
Sif Gudbrandsdottir ◽  
Marie Brimnes ◽  
Tania Kollgaard ◽  
Hans Carl Hasselbalch ◽  
Claus Henrik Nielsen
Keyword(s):  
B Cells ◽  
Autoimmune Diseases ◽  
B Cell ◽  
Research Funding ◽  
Immune Thrombocytopenia ◽  
Lower Proportion ◽  
Surface Markers ◽  
Healthy Controls ◽  
Cell Functions ◽  
Primary Immune Thrombocytopenia

Abstract Background B-cell depletion with rituximab (RTX) is widely accepted as first- or second-line therapy in primary immune thrombocytopenia (ITP), but it is still unclear how RTX mediates its positive effect in ITP patients. RTX has been reported to induce a reduced titer of platelet antibodies. However, this finding is inconsistent and other B-cell functions, such as the ability to secrete cytokines or to function as antigen-presenting cells for T cells, may be involved in the pathogenesis of ITP. Evidence suggests that B cells participate in the regulation of autoimmune diseases by virtue of their ability to produce the regulatory cytokines interleukin (IL)-10, IL-35, or transforming growth factor β. The various functions of B cells involved in the pathogenesis of autoimmune diseases can in part be deducted by their phenotype as recognized by measurement of specific surface markers and cytokine secretion. Materials and Methods We previously conducted a trial involving 137 newly diagnosed adult ITP patients randomized to treatment with RTX (375 mg/m2/week for 4 weeks) + dexamethasone (DXM) (40 mg/day for 4 days repeated up to 6 cycles) or DXM monotherapy. From this cohort, we identified 16 patients with available samples of peripheral blood mononuclear cells (PBMCs) at baseline and 12 months after treatment; 9 patients from the RTX+DXM group, 7 patients from the DXM group. Seven anonymous blood donors served as healthy controls. PBMCs were incubated for 18 h at 37°C under 5% CO2 in RPMI-1640 containing 10% (v/v) serum from healthy blood group AB donors, either alone or stimulated with 10 µg/ml CpG oligodeoxynucleotides. Expression of the cell-surface markers CD5, CD27, CD25 and CD19, and intracellular content of IL-6 and IL-10 were measured by flow cytometry. Results All patients responded to therapy and were in complete or partial remission at 12 months. Patient characteristics are listed in table I. We observed a significant increase in the proportion of CD5+ B cells 12 months after treatment with RTX+DXM compared to baseline (p < 0.01, Fig. 1A). The percentage of CD27+ memory B cells was significantly decreased at 12 months compared to baseline in patients receiving RTX+DXM (p < 0.05, Fig. 1B), and there was an inverse correlation between platelet numbers and the proportion of CD27+ B cells (R = -0.71; p < 0.05). The proportion of CD25+ B cells tended to decrease in patients treated with RTX+DXM, and was lower at 12 months than in patients treated with DMX only (p < 0.05, Fig 1C). PBMCs from ITP patients contained a lower proportion of IL-10+ B cells (p < 0.01) as well as a lower proportion of B cells producing IL-6 (p < 0.01) at baseline than PBMCs from healthy controls. At 12 months the low proportions had normalized in both treatment groups (Fig. 2). Conclusion B cells from ITP patients treated with RTX+DXM contained a high proportion of CD5+ B cells and low proportions of CD25+ and CD27+ B cells. Before treatment, B cells from ITP patients contained low frequencies of IL-10+ and IL-6+ B cells. Treatment with RTX + DXM or DXM alone reverted these aberrancies to normal. The increase in IL-10+ B cells as well as CD5+ B cells, which may represent overlapping subsets, is compatible with induction of Bregs and may support Treg development. Given the role of CD5+ B cells in maintenance of tolerance, the high frequency of these cells, which has also been observed after RTX therapy in rheumatoid arthritis, is compatible with amelioration of disease. Table 1 Table 1. Disclosures Gudbrandsdottir: GSK: Research Funding; Amgen: Research Funding.

A Plasma Clot Lysis Assay Based on the Release of Fibrin Degradation Products: Application to the Diagnosis of Hypofibrinolytic States

1990 ◽  
Vol 63 (01) ◽  
pp. 076-081 ◽  
Author(s):  
Pascale Gaussem ◽  
Sophie Gandrille ◽  
Pascale Molho-Sabatier ◽  
Loïc Capron ◽  
Jean-Noël Fiessinger ◽  
...  
Keyword(s):  
Degradation Products ◽  
Venous Occlusion ◽  
Lower Limbs ◽  
Clot Lysis ◽  
Plasma Clot ◽  
Vein Thrombosis ◽  
Fibrin Degradation Products ◽  
Before And After ◽  
Euglobulin Clot Lysis Time ◽  
Pai 1

SummaryUsing a monoclonal antibody-based assay, we measured the fibrin degradation product release in the supernatant of plasma clots obtained before and after venous occlusion (VO) in 30 patients with definite or suspected vascular thrombosis (19 definite and 2 suspected deep vein thrombosis, 6 recurrent superficial thrombophlebitis, 3 arterial occlusions of lower limbs). tPA and PAI-1 concentrations were determined using ELISA assays; the post-occlusion values were corrected for haemoconcentration. The increase in tPA during VO was correlated with haemoconcentration (r = 0.74), but 3 patients had ineffective VO (<2% increase in proteins). The fibrinolytic response to VO was evaluated using the shortening of the time necessary for the release of 200 μg of fibrin degradation products per mg of fibrinogen (Δ T 200). Two among the 27 patients with effective VO were bad responders with a Δ T 200 <3 h (whereas all the others had Δ T 200 >10 h). These patients had respectively a deficient tPA release (Δ tPA = 1 ng/ml) and an elevated PAI-1 level at rest (33 ng/ml). Several other patients were bad responders in terms of tPA release or of shortening of the euglobulin clot lysis time but they had a normal Δ T 200. This plasma clot test reflects the ability of free tPA to bind to fibrin (the amount of which depends on the level of tPA and PAI-1), and may be useful in the diagnosis of a hypofibrinolytic state.

Functional Properties of p-Anisoylated Plasmin-Staphylokinase Complex

1993 ◽  
Vol 70 (02) ◽  
pp. 326-331 ◽  
Author(s):  
H R Lijnen ◽  
B Van Hoef ◽  
R A G Smith ◽  
D Collen
Keyword(s):  
Human Plasma ◽  
Rate Constant ◽  
Time Course ◽  
Bolus Injection ◽  
Similar Rate ◽  
Clot Lysis ◽  
Lag Phase ◽  
Plasma Clot ◽  
Rapid Clearance ◽  
Stoichiometric Complex

SummaryThe kinetic and fibrinolytic properties of a reversibly acylated stoichiometric complex between human plasmin and recombinant staphylokinase (plasmin-STAR complex) were evaluated. The acylation rate constant of plasmin-STAR by p-amidinophenyl-p’-anisate-HCI was 52 M-1 s-1 and its deacylation rate constant 1.2 × 10-4 s-1 (t½ of 95 min) which are respectively 50-fold and around 3-fold lower than for the plasmin-streptokinase complex. The acylated complex was stable as evidenced by binding to lysine-Sepharose. However, following an initial short lag phase, the acylated plasmin-STAR complex activated plasminogen at a similar rate as the unblocked complex, whereas the acylated plasmin-streptokinase complex did not activate plasminogen. These findings indicate that STAR, unlike streptokinase, dissociates from its acylated complex with plasmin in the presence of excess plasminogen. In agreement with this hypothesis, the time course of the lysis of a 125I-fibrin labeled plasma clot submerged in citrated human plasma, is similar for acylated plasmin-STAR, unblocked plasmin-STAR and free STAR (50% clot lysis in 2 h requires 12 nM of each agent). The plasma clearances of STAR-related antigen following bolus injection in hamsters were 1.0 to 1.5 ml/min for acylated plasmin-STAR, unblocked plasmin-STAR and free STAR, as a result of short initial half-lives of 2.0 to 2.5 min.The dissociation of the anisoylated plasmin-STAR complex and its consequent rapid clearance suggest that it has no apparent advantages as compared to free STAR for clinical thrombolysis.

scholarly journals Analysis of Interleukin-17 Levels in Patients with Thrombocytopenia

Biomedika ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 68-73
Author(s):  
Lidwina Septie Christyawardani ◽  
Mansyur Arief ◽  
Uleng Bahrun
Keyword(s):  
Blood Circulation ◽  
Immune Thrombocytopenia ◽  
Research Unit ◽  
Comparative Test ◽  
P Value ◽  
Interleukin 17 ◽  
Platelet Production ◽  
Immune Mediated ◽  
Significant Difference ◽  
Primary Immune Thrombocytopenia

Thrombocytopenia or platelet deficiency is a condition, in which platelet level in the blood circulation is below normal, which is less than 150,000 cells/µl. Thrombocytopenia is classified into some conditions, including decreased platelet production, increased need for platelets, and other thrombocytopenia. The need for increased platelets can be subdivided into primary immune thrombocytopenia, secondary immune thrombocytopenia, non-primary ITP, and thrombocytopenia that are not immune-mediated. Several cytokines play a role in the process of thrombocytopenia, one of which is Interleukin-17 (IL-17) that will be further discussed in this study. A previous study reported that IL-17 production increased in ITP and cITP patients. The objective of this study was to analyze the IL-17 levels and figure out the differences in IL-17 levels in the serums of patients with primary ITP and secondary ITP. The samples were taken from Wahidin Sudirohusodo Hospital and the specimens were examined in the Research Unit Laboratory of the Faculty of Medicine, Universitas Hasanuddin/Hospital of Universitas Hasanuddin. The comparative test resulted in p-value = 0.005, where p <α = 0.05; and therefore, there was a significant difference between IL 17 levels in ITP and non-primary ITP.

Sex Differences in the Determinants of Fibrinolytic Activity

1998 ◽  
Vol 79 (03) ◽  
pp. 587-590 ◽  
Author(s):  
J. A. Cooper ◽  
D. J. Howarth ◽  
T. W. Meade ◽  
G. J. Miller ◽  
P. K. MacCallum
Keyword(s):  
Plasminogen Activator ◽  
Whole Blood ◽  
Fibrinolytic Activity ◽  
Plasminogen Activator Inhibitor ◽  
Tissue Type ◽  
Clot Lysis ◽  
Significant Difference ◽  
Main Determinants ◽  
Activator Inhibitor Type ◽  
Pai 1

SummaryImpaired whole blood fibrinolytic activity (FA), measured by the dilute clot lysis time (DCLT), is associated with first episodes of ischaemic heart disease (IHD) in the Northwick Park Heart Study in men, especially under 55 years, and in women. In a community-based study to investigate possible determinants of the DCLT, and therefore to assess which fibrinolytic components might be predictors of first IHD events, we measured fibrinolytic variables in a sub-sample of 150 healthy adults (73 males, 77 females) randomly selected from a single general practice.Most of the variance in DCLT (68% in men, 63% in women) was explained by tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type-1 (PAI-1) activities. In multiple regression analysis there was a significant difference in the strength of the association of t-PA activity with DCLT in men compared to women (test for interaction p = 0.05), the association of t-PA activity with DCLT being significant in males but not in females. Plasma PAI-1 activity was strongly associated with DCLT in both sexes. There was no independent association of DCLT with plasma fibrinogen, t-PA antigen, other fibrinolytic inhibitors, body mass index, serum lipids or C-reactive protein.Plasma PAI-1 activity in females and both t-PA and PAI-1 activities in males are the main determinants of whole blood FA measured by DCLT. It is therefore likely that these modulators of the plasma fibrinolytic system are associated with the onset of first clinical episodes of IHD. Elevated levels of t-PA antigen were positively associated with DCLT after adjustment for age and sex and therefore indicate impaired rather than enhanced FA. Further studies of the association of FA with risk of IHD should include not only “global” measures but also assessment of t-PA and PAI-1 activities, particularly as our results suggest that their associations with IHD may differ in men and women.

The Ratio of Treg/Th17 Cells Correlates with the Platelet Number in Different Disease State of Primary Immune Thrombocytopenia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4649-4649
Author(s):  
Lili Ji ◽  
Feng Li ◽  
Yanxia Zhan ◽  
Fanli Hua ◽  
Shanhua Zou ◽  
...  
Keyword(s):  
Autoimmune Diseases ◽  
Th17 Cells ◽  
Immune Thrombocytopenia ◽  
Conflicts Of Interest ◽  
Disease Onset ◽  
Treg Cells ◽  
Healthy Controls ◽  
T Helper ◽  
Platelet Number ◽  
Primary Immune Thrombocytopenia

Abstract Abstract 4649 Background: Primary immune thrombocytopenia (ITP) is an autoimmune heterogeneous disorder that is characterized by decreased platelet count. Regulatory T (Treg) cells and T helper type 17 (Th17) cells are two subtypes of CD4+T helper (Th) cells. They play opposite roles in immune tolerance and autoimmune diseases, while they share a common differentiation pathway. The imbalance of Treg/Th17 has been demonstrated in several autoimmune diseases. In this study, we aimed to investigate the ratio of the number of Tregs to the number of Th17 cells in ITP patients and evaluate the clinical implications of the alterations in this ratio. Methods: Thirty adult patients with newly diagnosed ITP enrolled in this study. Patients who needed treatment had been clinically followed up for 12 months. The percentages of CD4+CD25hiFoxp3+ Treg cells and CD3+CD4+IL-17-producing Th17 cells in these patients and healthy controls (n=17) were longitudinally analyzed by flow cytometry. Results: The percentage of Treg cells in ITP patients was significantly lower than that of healthy controls and the percentage of Th17 cells increased significantly at disease onset. It is suggested that the ratio of Treg/Th17 correlated with the disease activity. Conclusion: The ratio of Treg/Th17 might be relevant to the clinical diversity of ITP patients, and this Treg/Th17 ratio might have prognostic role in ITP patients. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Absence of Hyperactivation of Fibrinolysis Explains the Lack of Hemostatic Efficacy of Prophylactic Tranexamic Acid (TXA) in Hypoproliferative Thrombocytopenia

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2094-2094
Author(s):  
Anton Ilich ◽  
Terry B. Gernsheimer ◽  
Darrell J Triulzi ◽  
Heather Herren ◽  
Siobhan P Brown ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Research Funding ◽  
Study Drug ◽  
Clot Lysis ◽  
Advisory Committees ◽  
Trial Investigator ◽  
Lysis Time ◽  
Pai 1 ◽  
Clot Lysis Time

Abstract Background: We previously reported the results of the A-TREAT study (American Trial Using Tranexamic Acid in Thrombocytopenia: NCT02578901). This randomized double-blind placebo-controlled trial demonstrated that TXA administration is not superior to placebo in preventing WHO grade 2 or higher bleeding in severely thrombocytopenic patients requiring supportive platelet transfusion following myeloablative therapy for hematologic disorders (Gernsheimer T., ASH 2020 Plenary Session). Here, we present results of the A-TREAT ancillary study - Fibrinolysis Evaluation in A-TREAT (FEAT). Blood samples were collected from a subset (n=115) of A-TREAT participants just prior to initiation of study drug (when the platelet count was &lt;30,000/µl) and at a later time point when TXA was at a steady state trough level (5 ±2 days following study drug initiation). Using global assays of fibrinolysis in plasma, our a priori hypotheses were that: 1] a baseline 'hyperfibrinolytic' profile would be associated with a higher proportion of grade 2+ bleeding; and 2] trough TXA levels would be associated with a 'hypofibrinolytic' profile and a lower proportion of grade 2+ bleeding. Methods: Fibrinolysis in platelet-free citrated plasma was assessed by 3 global assays: euglobulin clot lysis time (ECLT), plasmin generation (PG), and tPA resistance clot lysis time (tPA-CLT) using previously described methods (Ilich A. RPTH 2020, Miszta A. JTH 2021). Trough plasma TXA concentration was measured using a validated tandem mass spectrometry assay. Individual fibrinolytic analytes (PAI-1, tPA, plasminogen, alpha2-antiplasmin and plasmin-antiplasmin complexes) were quantified by ELISA. Results: Baseline samples did not demonstrate a hyperfibrinolytic profile by ECLT. To the contrary, ECLT values were significantly increased compared to healthy controls (figure 1). Furthermore, none of the measured fibrinolytic parameters (ECLT, tPA-CLT, total PAI-1, tPA, plasminogen, alpha2-antiplasmin or plasmin-antiplasmin complexes) at baseline were associated with a greater risk of grade 2+ bleeding during follow up, regardless of treatment arm. On the follow-up samples, neither pharmacokinetic (trough TXA concentration) nor pharmacodynamic parameters (PG or tPA-CLT) were associated with bleeding severity. A high inter-patient variability of TXA trough concentrations was noted in the treatment arm (min-max: 0.7-10 ug/ml), and drug levels correlated strongly with global fibrinolysis assessment by PG (Spearman r, -0.78, 95% CI -0.88 - -0.62) and tPA-CLT (r, 0.74, 0.56 - 0.85) (figure 2). Conclusions: 1] No evidence of fibrinolytic hyperactivation was observed in these thrombocytopenic patients; 2] trough TXA concentrations varied significantly between patients receiving the same dosing schedule; and 3] tPA-CLT and PG parameters correlated well with TXA plasma concentrations and thus may be used to estimate the extent of fibrinolytic inhibition in patients treated with TXA. Discussion: The absence of hyperactivation of endogenous fibrinolysis in this study is in contrast to our recent findings in trauma. Specifically, we reported that almost half of trauma patients demonstrated evidence of fibrinolytic hyperactivation (by ECLT) on admission (Ilich A. Thromb Res, 2021). Since TXA has been shown to reduce mortality due to bleeding in trauma (CRASH II, Lancet, 2010) and given that baseline hyperfibrinolysis is common in trauma, we hypothesize that the absence of fibrinolytic hyperactivation observed in the A-TREAT study patients likely explains the clinical lack of efficacy of TXA. Figure 1 Figure 1. Disclosures Gernsheimer: Amgen: Honoraria; Novartis: Honoraria; Principia: Research Funding; Rigel: Research Funding; Cellphire: Consultancy; Dova: Consultancy; Sanofi: Consultancy. Triulzi: Fresenius Kabi: Membership on an entity's Board of Directors or advisory committees; Realta: Membership on an entity's Board of Directors or advisory committees. Wolberg: CSL Behring: Consultancy; Bristol Myers Squibb: Research Funding; Takeda: Research Funding. Key: Takeda: Research Funding; BioMarin: Honoraria, Other: Participation as a clinical trial investigator; Sanofi: Consultancy; Grifols: Research Funding; Uniqure: Consultancy, Other: Participation as a clinical trial investigator.

scholarly journals Abnormal Microenvironment of Bone Marrow B Lymphocytes in Patients with Primary Immune Thrombocytopenia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3759-3759
Author(s):  
Tianshu Yu ◽  
Ming Hou ◽  
Xinguang Liu ◽  
Panpan Han
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Lymphocytes ◽  
Chemokine Receptors ◽  
Immune Thrombocytopenia ◽  
Plasma Cells ◽  
Healthy Donors ◽  
Significant Difference ◽  
Primary Immune Thrombocytopenia ◽  
Development And Differentiation

Abstract BACKGROUNDS: Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by peripheral blood platelet count<100x10^9/L and increased risk of bleeding, but its exact pathogenesis remains unclear. Previous researches mostly emphasized on periphral blood, in order to elucidate the pathogenesis and provide new strategies for treatment, a series of studies about bone marrow B cells were carried out in our investigation. METHODS: 5ml bone marrow blood samples from 11 newly diagnosed ITP patients and 7 allo-HSCT healthy donors were collected into heparin anticoagulant tubes , bone marrow mononuclear cells (BMMCs) were separated with Ficoll density gradient-centrifugation in two hours. Different subsets of B lymphocytes were determined by multicolor flow cytometry including naive B cells, total memory B cells , plasma cells and regulatory B cells (Bregs) ,as well as some chemokine receptors of B cells (CXCR5, BAFFR, BCMA, TACI) . RNA were extracted from BMMCs using Trizol reagent, transcription factors related to development and differentiation of B cells (PRDM1, Pax5, IRF-4, XBP1) were detected by real-time PCR. RESULTS: The percentage of B cells (CD19+) in bone marrow lymphocytes in ITP patients was significantly lower than that in healthy donors (6.16±0.74% vs. 17.28±2.43%, P < 0.0001). The proportion of naive B (CD19+CD27-) in B cells was also lower compared with normal controls (59.11±7.60% vs. 81.58±4.00%, P=0.041), and the proportion of memory B (CD19+CD27+) was higher(40.17±7.67% vs. 18.01±3.89%, P=0.045),but there was no significant difference in plasma cells (CD19-CD138+). Besides,there was a decrease of Breg (CD19+CD24highCD38high) in ITP patients compared with healthy donors (20.33±5.05% vs. 57.98±9.76% , P = 0.008), and its percentage of total lymphocytes was also significantly lower unsurprisingly (1.38±0.38% vs. 12.23±2.88%, P < 0.001). The level of BAFFR in mature B cells was elevated in ITP patients (80.72±4.53% vs. 45.81±8.49%, P = 0.002). However, no significant difference was observed in other three chemokine receptors. All four Transcription factors related to B cell development and differentiation was not found to be significantly different between ITP patients and healthy controls. CONCLUSIONS: Our results showed that memory B cells which represent the active form were increased, and Bregs which mediate immune tolerance were much more decreased in ITP patients. As BAFFR is the only specific receptor of B cell activating factor(BAFF), its elevated expression suggested the BAFF-BAFFR system enhanced chemotactic function of B cells in ITP patients. All those results indicated that the bone marrow B cells in patients with ITP were in a state of immune overstimulation, this may potentially constitute a novel therapeutic target. Figure. Figure. Disclosures No relevant conflicts of interest to declare.

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