Constitutive Activation of Hemostasis in Children with Sickle Cell Disease.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1216-1216
Author(s):  
MacGregor Steele ◽  
Suzan Williams ◽  
Fred Pluthero ◽  
K.W. Annie Bang ◽  
Ran Goldman ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Steady State ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Whole Blood ◽  
Surface Expression ◽  
Hypercoagulable State ◽  
Cell Disease ◽  
Normal Children

Abstract Recent studies of sickle cell disease (SCD) suggest that hemostatic activation is a key aspect of pathophysiology, leading to clinical consequences such as vaso-occlusive crises and stroke. In many of these studies a SCD-associated hypercoagulable state has been inferred from markers suggestive of increased hemostatic activity, such as elevated levels of plasma thrombin-antithrombin complexes and tissue factor-containing microparticles. As part of a study using a broad-spectrum approach to explore the relationships among various aspects of normal and abnormal hemostasis in SCD we used a whole-blood coagulation assay (thromboelastography, TEG) to directly assess global hemostatic activation in children with SCD defined by genotype (SS and SC), together with a group of unaffected children. We also assessed platelet activation and procoagulant surface expression in platelets and red blood cells (RBCs) using flow cytometry. Eligible SCD subjects included:patients with painful crisis assessed at two time points: hospital admission (crisis group) and clinic follow-up appointment (follow-up group);patients not in crisis attending a regular clinic appointment (steady-state group). Patients were ineligible if they had received a recent blood transfusion, hydroxyurea, anticoagulants or aspirin. The results of TEG assays with citrated whole blood showed that compared to SC patients (n = 16) and normal children (n = 16), SS patients (n = 45) had significantly (p<0.001) earlier clotting onset (mean R times were 4.5, 6.5 and 7.6 minutes for SS, SC and normals respectively) and significantly (p<0.001) higher rates of clotting (mean maximum clotting rates were 16.8, 12.6 and 10.9 mm/min for SS, SC and normals respectively). TEG clotting onset and maximum clotting rates were not significantly different among steady-state, crisis and follow-up groups of children with SCD (both SS and SC genotypes), nor between sexes within each study group. Whole blood flow cytometry revealed that platelet GPIIb/IIIa activation (PAC-1 binding) was significantly elevated (p<0.05) in SCD patients relative to normal children. In addition, markers of RBC procoagulant surface expression (RBC annexin A5 binding) and RBC-platelet aggregates were elevated in SCD patients compared to normal children. These results indicate that children with the SS genotype have an activated hemostatic system relative to normal and SC genotype children, and that this hypercoagulable state is maintained during sickle cell crisis as well as during steady state. It remains to be determined whether pharmacological interventions and/or RBC transfusions which improve clinical outcomes in SCD patients modify their constitutively hypercoagulable state.

Heme Induces Endothelial Tissue Factor Expression: Potential Role in Hemostatic Activation in Patients with Intravascular Hemolysis Including Sickle Cell Disease.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1902-1902
Author(s):  
Yamaja Setty ◽  
Suhita Gayen Betal ◽  
Jie Zhang ◽  
Nigel S Key ◽  
Marie Stuart
Keyword(s):  
Flow Cytometry ◽  
Endothelial Cells ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Whole Blood ◽  
Dependent Manner ◽  
Cell Disease ◽  
Intravascular Hemolysis ◽  
Tnf Α ◽  
Endothelial Tissue

Abstract Plasma levels of heme in the 20 to 600 μM range are found in clinical conditions associated with intravascular hemolysis including paroxysmal nocturnal hemoglobinuria and sickle cell disease, conditions also associated with a thrombotic tendency. Objectives: To investigate whether heme, an inflammatory mediator and a product of intravascular hemolysis in patients with hemolytic anemia including sickle cell disease (SCD), could modulate hemostasis by an effect on endothelial tissue factor (TF) expression. Additionally, in SCD patient-related studies, we assessed whether any association existed between whole blood TF activity (WBTF) and levels of surrogate markers of intra-vascular hemolysis including lactate dehydrogenase (LDH) and reticulocyte counts. Methods: Following incubation of human endothelial cells (from umbilical vein and/or lung microvasculature) with heme (1 to 100 μM) for various times (30 minutes to 8 hours), levels of TF protein were assessed using ELISA, flow cytometry and/or Western blotting; and TF mRNA by a semi-quantitative RT-PCR. An assay for TF functional activity was performed using a chromogenic tenase activity kit where specificity of TF activity was tested in antibody-blocking experiments. Three TF-specific antibodies including a rabbit polyclonal and two mouse monoclonal (clones hTF-1 and TF9-10H10) antibodies were used in assays involving TF protein analysis. All experiments were performed in media containing polymyxin B to neutralize any potential endotoxin contamination. In patient-related studies, 81 subjects with SCD (1 to 21 years) were evaluated for levels of WBTF, LDH, and reticulocyte counts and data analyzed for potential relationships. Results: Heme induced TF protein expression on the surface of both macro- and micro-vascular endothelial cells in a concentration-dependent manner with 12- to 50-fold induction noted (ELISA assays) between 1 and 100 μM heme (P<0.05, n=3 to 6). Complementary flow cytometry studies showed that the heme-mediated endothelial TF expression was quantitatively similar to that induced by the cytokine TNF-α. Heme also up-regulated endothelial expression of TF mRNA (8- to 26-fold, peak expression at 2 hours postagonist treatment), protein (20- to 39-fold, peak expression at 4 hours) and procoagulant activity (5- to 13-fold, peak activity at 4 hours post-agonist treatment) in a time-dependent manner. Time-course of heme-mediated TF antigen expression paralleled induction of procoagulant activity with antibody blocking studies demonstrating specificity for TF protein. Potential involvement of endogenously released cytokines including IL-1α and TNF-α in mediating the heme effect was next explored. We found that the latter cytokines are not involved, since antibodies against IL-1α and TNF-α, and an IL-1- receptor antagonist failed to block heme-induced endothelial TF expression. Inhibition of heme-induced TF mRNA expression by sulfasalazine and curcumin suggested that the transcription factor NFκB was involved in mediating heme-induced effect. In patient-related studies, whole blood TF levels in SCD correlated positively with both LDH (r=0.72, p<0.000001), and reticulocyte count (r=0.60, p<0.000001). Conclusions: Our findings demonstrate that heme induces TF expression in endothelial cells, and that the observed effects occurred at patho-physiologically relevant heme concentrations. Our results suggest that heme-induced endothelial TF expression may provide a pathophysiologic link between the intravascular hemolytic milieu and the hemostatic perturbations previously noted in patients with hemolytic anemia including sickle cell disease.

A Novel Connection Between Stress Erythropoiesis and Coagulation Activation in Sickle Cell Disease.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 905-905
Author(s):  
Julia E. Brittain ◽  
David Manly ◽  
Leslie V. Parise ◽  
Nigel Mackman ◽  
Kenneth I. Ataga
Keyword(s):  
Flow Cytometry ◽  
Sickle Cell Disease ◽  
Tissue Factor ◽  
Sickle Cell ◽  
Whole Blood ◽  
Conflicts Of Interest ◽  
Cell Disease ◽  
Coagulation Activation ◽  
Monocytic Cells ◽  
Stress Erythropoiesis

Abstract Abstract 905 Introduction: Sickle cell disease (SCD) is associated with a hypercoagulable state. Multiple studies show that plasma from these patients exhibit: 1) increased thrombin generation; 2) decreased levels of natural anticoagulant proteins; and 3) a defect in the activation of fibrinolysis. The mechanism of coagulation activation in SCD is presumed to be multi-factorial, with contributions from abnormal erythrocyte phospholipid asymmetry and induction of tissue factor (TF) following hemolysis. In addition, hemolysis in SCD leads to elevated levels of erythropoietin (EPO) in patients, increased reticulocyte counts and the presence of stress (or shift) reticulocytes in circulating blood. These stress reticulocytes retain expression of the α4b1 integrin and are demonstrably adhesive to vascular factors in SCD. We have previously reported that these stress reticulocytes bind to blood monocytes in SCD patients via the α4b1 integrin, but the effect of this interaction on either cell remained unknown in SCD. Objective: With the increasing evidence that hemolysis and subsequent stress erythropoiesis associates with coagulation activation, we sought to evaluate the role of erythropoietin and the effect of stress reticulocyte adhesion to monocytes on coagulation activation in SCD patients. Methods: Coagulation activation in plasma samples was examined by evaluating TF activity on microparticles derived from patients with SCD. Stress reticulocytes were visualized and enumerated from these same patients using Wright Giemsa stained blood smears counter stained with new methylene blue to detect reticulocytes. Reticulocytes were scored as a stress reticulocytes based on the amount of punctuate reticular material, cell size, and presence of nuclear material. Stress reticulocyte induction of monocyte tissue factor expression was measured by flow cytometry after incubation of THP-1 monocytic cells with purified SS RBCs or control RBCs. To determine if induced THP-1 TF expression was due stress reticulocyte binding, THP-1 TF expression was examined in the presence or absence of known inhibitors of the monocyte/stress reticulocyte interaction. TF expression on CD14+ monocytes was examined in whole blood from SCD patients using flow cytometry. Plasma erythropoietin levels were quantified by ELISA. Results: We found that direct binding of the stress reticulocyte increased THP-1 TF expression 2.5 fold. This increase in TF expression was completely ablated by function blocking antibodies against the α4 integrin, but not by an isotype-matched control IgG. In whole blood samples, we also found increased TF expression on CD14+ monocytes with stress reticulocytes directly bound, compared to those monocytes in the same patient without stress reticulocytes bound (p = 0.002, n =3).We noted a strong correlation between stress reticulocyte count and TF activity on plasma microparticles in SCD (rspearman = 0.8656, CI = 0.5382 – 0.9660, p = 0.0006, n=11). Furthermore, we found that EPO induced α4b1 activation on the stress reticulocyte. This activation may promote both adhesion to the monocyte and an increase in TF expression. Consequently, we noted a strong trend towards an association of EPO with microparticle TF activity in SCD (rspearman = 0.5740, CI=-0.06 – 0.8780, p=0.068, n= 11) suggesting that EPO, by promoting the interaction between the stress reticulocyte and the monocyte, may contribute to TF activity in SCD. Conclusion: Taken together, we find that stress reticulocyte adhesion to monocytes and monocytic cells induces TF expression and may promote TF activity in patients. These data suggest a novel connection between stress erythropoiesis and coagulation activation in SCD. Disclosures: No relevant conflicts of interest to declare.

Report on the International Co-Operative Study of the Effects of L-Selectin Gene Polymorphisms on the Development of Complications in Sickle Cell Disease.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3775-3775
Author(s):  
Iheanyi Okpala ◽  
Cynthia C. Ugochukwu ◽  
Panagiotis Pantelidis ◽  
Baba Inusa ◽  
Obike Ibegbulam ◽  
...  
Keyword(s):  
Steady State ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Surface Expression ◽  
Control Individual ◽  
Acute Chest Syndrome ◽  
Nucleotide Polymorphisms ◽  
Cell Disease ◽  
Increased Risk ◽  
Significant Difference

Abstract Our previous study showed that patients with sickle cell disease (SCD) and high steady-state expression of the adhesion molecules L-selectin and αMβ2 integrin on leukocytes developed complications [Blood. 2002;100(suppl):11a. Eur J. Haematol. 2002; 69:135–144]. The aim of this study was to find out if L-selectin protein expression by leukocytes and the development of complications in SCD are affected by previously described single nucleotide polymorphisms within the coding regions of the gene. To detect F206L, T49S and P213S polymorphisms we determined the L-selectin genotype in 142 HbSS patients (64M, 78F, age 2 – 62 yr, mean 27 yr ±12); and 102 racially-matched HbAA controls with similar age and sex distribution. The T49S and P213S amino acid changes in L-selectin are respectively associated with increased risk of vasculopathy and nephropathy; important features of SCD. [Hum Genet. 1996; 97:15–20. Am. J. Hum. Genet.2002; 70: 781–786]. All HbSS patients were evaluated for disease complications. Steady-state expression of L-selectin on neutrophils, lymphocytes and monocytes was measured by flow cytometry in 44 HbSS patients. With respect to F206L polymorphism, 100/142 (70%) patients and 73/102 (72%) controls were FF homozygous, 42 patients and 28 controls were heterozygous FL, and 1 control individual was LL homozygous. There was no significant difference in distribution of the polymorphic variants between patients and controls [Chi-squared (X2) = 0.1, p>0.05]. In codon 213, 48 (33.8%) patients and 42 (41.2%) controls were PP homozygous, 91 patients and 55 controls PS heterozygous, 1 patient and 5 controls SS homozygous [X2 =1.9, p>0.05]. With regard to the T49S polymorphism, 100% of the patients and controls were TT homozygous. At least one complication of SCD was observed in 110 SCD patients; 32 had uncomplicated disease. The most common complications observed were avascular joint necrosis (n=39), sickle nephropathy (n=31), stroke (n=25) and acute chest syndrome (n=20). The observed frequencies of FF genotype in codon 206 among patients with complications (74), and without complication (26) were not significantly different from the expected values [X2 = 2.37, p>0.05]. Similarly, none of the other genotypes (FL, PP, PS) was significantly associated with complications of SCD. Of the 44 patients in who leukocyte L-selectin expression was measured, 31 turned out to be FF homozygous in codon 206, and 13 FL. No significant differences were observed between FF and FL patients in the mean levels of L-selectin expression by neutrophils (FF: 4.00+ 4.56 vs FL: 3.24+ 3.4), monocytes (FF: 4.30+ 5.6 vs FL: 2.56+ 3.39) or lymphocytes (FF: 2.61+ 3.02 vs FL: 2.11+ 2.0); p>0.05. Similarly, the P213S polymorphism had no effect on the level of L-selectin expression. The findings suggest that neither F206L nor P213S L-selectin gene polymorphism predisposes to high leukocyte surface expression of this adhesion molecule, or the development of complications in SCD.

Hemolysis-Associated Elevation in Tricuspid Regurgitation Velocity Predicts Reduction in Six-Minute Walk Distance After Two Years of Follow up in Children and Adolescents with Sickle Cell Disease.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 574-574
Author(s):  
Victor R. Gordeuk ◽  
Lori Luchtman-Jones ◽  
Andrew D. Campbell ◽  
Sohail R Rana ◽  
Mehdi Nouraie ◽  
...  
Keyword(s):  
Steady State ◽  
Sickle Cell Disease ◽  
Children And Adolescents ◽  
Sickle Cell ◽  
Cell Disease ◽  
Walk Distance ◽  
Six Minute Walk Test ◽  
Minute Walk Distance ◽  
Minute Walk

Abstract Abstract 574 Background. Elevated tricuspid regurgitation velocity (TRV) as determined by echocardiography correlates with elevated systolic pulmonary artery pressure and is associated with increased morbidity and mortality in adults with sickle cell disease. The importance of elevated TRV in children and adolescents with sickle cell disease is not known. The Pulmonary Hypertension and the Hypoxic Response in SCD (PUSH) study is an ongoing, longitudinal and observational multicenter study of children with sickle cell disease. Methods. Baseline echocardiography and six-minute walk test were performed prospectively in 361 children and adolescents with sickle cell disease at steady state and then repeat studies were performed in 209 after a median of 22 months of follow up (range 10 months to 36 months), also at steady state. A hemolytic component was derived by principal component analysis of baseline values for reticulocyte count, lactate dehydrogenase, aspartate aminotransferase and total bilirubin. Results. TRV or six-minute walk test were measured at both baseline and follow-up in 193 patients. Twenty-one of these 193 patients had elevated TRV of 2.60 m/sec or higher at baseline. Elevated baseline TRV was associated with high hemolytic rate in 15 patients, defined as hemolytic component above the median for the population studied, and with lower hemolytic rate in six patients. Elevated baseline TRV with high hemolytic rate predicted elevated TRV at follow up (odds ratio 7.7; 95% confidence interval [CI] 2.5 to 24.2; P <0.001) but elevated baseline TRV with lower hemolytic rate did not (odds ratio 1.6; 95% CI 0.2 to 14.1; P = 0.7). Elevated baseline TRV with high hemolytic rate also predicted a decline in the six-minute walk distance by 10% or more at follow-up (hazard ratio 3.9; 95% CI 1.4 to 10.7; P = 0.009). In contrast, higher cardiac output as measured by the left ventricular end diastolic dimension z-score was associated with reduced risk for a decline in the walk distance (hazard ratio 0.7; 95%CI 0.6 to 0.9; P = 0.006). Conclusion. Steady-state TRV elevation in association with a high hemolytic rate occurs on screening in about 8% of children and adolescents with sickle cell disease and is predictive of elevated TRV and reduced six-minute walk distance after approximately two years of follow. Such children may be at risk for adverse clinical consequences of pulmonary hypertension as young adults. Further studies are indicated to identify the molecular mechanisms and to develop appropriate medical management for children and adolescents with this complication. Disclosures: No relevant conflicts of interest to declare.

Two Independant Assays Demonstrate High Phospholipid Procoagulant Activity In Poor Platelet Plasma of Sickle Cell Disease Children.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1630-1630
Author(s):  
Alina Ferster ◽  
Denis fondjie Noubouossie ◽  
Anne C Demulder ◽  
Francis V. Corazza ◽  
Phu-Quoc Le
Keyword(s):  
Steady State ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Specific Treatment ◽  
Positive Control ◽  
Procoagulant Activity ◽  
Hypercoagulable State ◽  
Clinical State ◽  
Cell Disease ◽  
Normal Controls

Abstract Abstract 1630 Sickle cell disease (SCD) is considered as a hypercoagulable state through still a mechanism poorly understood. Our hypothesis is that poor platelet plasma (PPP) from SCD children may contain a high phospholipids procoagulant activity. This study aimed 1° at using and comparing two different assays to detect the procoagulant activity of endogenous phospholipids (ePL) in the PPP of SCD children in steady state compared to normal controls, 2° at assessing the influence of the clinical state and treatment on this procoagulant activity. Patients: A group of 30 SCD children aged between 2 – 20 years (median=9, 16 males, 14 females) were studied: 12/30 didn't receive any specific treatment, 6/30 were chronically transfused (TRX) and 12/30 were treated by hydroxyurea (HU). 11/30 were previously admitted because of a vaso-occlusive crisis (VOC). 24 SCD patients were HbSS, 4 HbSC, and 2 HbSβ. Controls: 18 remaining samples from children aged between 3 – 20 years (median=9, 11 males, 7 females) undergoing minor elective surgery, with no history of coagulation disorder, normal routine coagulation tests, normal CRP, liver and kidney functions tests. The controls were not matched for the age neither sex. Venous blood was collected into 0,109M citrated tubes using a 23G butterfly needle. PPP was obtained after 2 steps of centrifugation (3200g for 15 min and 16000g for 2 min) within 2 hours following venipuncture, and stored at -80°C. Procoagulant activity of ePL was assessed using two independent assays: a commercial fully automated factor Xa-based clotting time assay (XACT: sec) as described by Exner et al (ProcoagPPL® Stago, Asnières sur Seine, France), and a thrombin generation assay (TGA) using calibrated automated thrombinography (CAT) as described by Hemker et al (Thrombinoscope®, Maastricht, The Netherland). TGA was triggered with 10pM tissue factor (TF) alone and with a combination of 10pM TF and 4μM synthetic PL (positive control). Four TGA parameters were analysed: lag time (LT), Peak, Velocity Index (VI) and Endogenous Thrombin Potential (ETP). For each parameter, the result was also expressed as a % of the positive control, to minimize the influence of age. Correlations were assessed between XACT and TGA parameters using the Spearman's coefficient. Group comparison was assessed using non parametric tests. Significant correlations were found between XACT and Peak (r= -0,76, p<0,0001), VI (r= -0,73, p<0,0001), ETP (r= -0,47, p<0,0001) measured without addition of PL, and also between XACT and % Peak (r= -0,73, p<0,0001), %VI (r= -0,63, p<0,0001) and % ETP (r= -0,60, p<0,0001). No correlation was found between XACT and LT (r= 0,20, p = 0,096). The table shows median and range values obtained from SCD patients in steady state as compared to those of normal controls, using both methods. The TGA values are those obtained with 10pM alone, and are also expressed as a percentage of positive control. Concerning the clinical state and treatment, XACT and all CAT parameters failed to show significant differences between subgroups of SCD (steady vs. CVO, n=11), and their treatment (TRX vs. HU vs. No specific treatment). For the patients undergoing chronic exchange transfusion, no significant difference was observed between the samples collected before and few hours after transfusion exchange. In SCD children in steady state, XACT is significantly shortened compared to normal controls. Velocity index and Peak thrombin are significantly increased when using a high TF concentration alone as trigger. Each test showed similar performance to detect a higher procoagulant activity of ePL in SCD patients, which could contribute to the hypercoagulable state observed in those patients. In our study, ePL procoagulant activity was not influenced by the clinical state, neither the type of treatment, but this could be due to the relatively small number of patients included till now. We are currently studying more patients to confirm our results in a larger group and in particular to analyze the effects of treatment. Disclosures: Noubouossie: Belgian Kid's Fund: Grant's recipient of the Belgian Kid's Funds.

scholarly journals Erythroid Chimerism Measurement As a Predictive Tool of Bone Marrow Transplantation Outcome in Sickle Cell Disease

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2028-2028
Author(s):  
Nicolas Hebert ◽  
Meghan Perkins ◽  
Ivan Sloma ◽  
Laura Bencheikh ◽  
Florence Beckerich ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Bone Marrow Transplantation ◽  
Sickle Cell Disease ◽  
Molecular Biology ◽  
Sickle Cell ◽  
Blood Cells ◽  
Marrow Transplantation ◽  
Cell Disease

Abstract Allogeneic bone marrow transplantation (BMT) is the only curative treatment available for sickle cell disease (SCD). The effectiveness of the treatment is primarily assessed by the chimerism rate, which is the fraction of cells derived from the donor's hematopoietic stem cells (HSCs) relative to the recipient's cells. New less toxic conditioning agents, described as reduced, nonmyeloablative (as opposed to myeloablative conditioning agents) are now used for BMT with sibling donors. Moreover, most sibling donors are sickle cell trait carriers (heterozygous A/S genotype). In the absence of a test performed on erythroid cells, the rate of chimerism is currently assessed either on different subpopulations of myeloid cells by molecular biology techniques or on hemoglobin measurement by chromatography (HPLC). However, the percentage of myeloid chimerism is rarely representative of the percentage of erythroid chimerism in these patients and HPLC cannot allow analysis at the single cell level. An easy-to-implement method for accurate measurement of fetal hemoglobin (HbF) content in individualized red blood cells (RBCs) has recently been developed (Hebert, et. al, AJH 2020). This method relies on flow cytometry for cell individualization and intracellular labeling of HbF with a fluorescent monoclonal antibody for quantification. Based on the same approach, we propose the use of monoclonal antibodies directed against adult hemoglobins (HbA0 and HbA2) or hemoglobin S (HbS). This strategy allows to discriminate, from a blood sample, the different RBC subpopulations coming from either the recipient or the donor, or from the transfusion associated with this procedure, thus allowing us to precisely determine the rates of erythroid chimerism in patients. As a proof of concept, we show here the evaluation of the percentage of erythroid chimerism during a longitudinal follow-up performed on 3 patients with SCD (P1 - 18 months, P2 - 4 months, and P3 - 4 months). The 3 patients received allogeneic BMT from a sibling A/S donor following nonmyeloablative conditioning consisting of the administration of an anti-CD52 antibody associated with radiotherapy (300 cGy TBI - total-body irradiation). We observed for P1 and P2 donor erythroid chimerism &gt;90% and &gt;95%, 1 and 2 months after BMT, respectively (measured after exclusion of transfused RBCs). These results are in accordance with the presence of most RBCs HbA- and HbS-positive, as determined by flow cytometry. In addition, the analysis of the reticulocyte (retic) subpopulations (CD71-positive cells) of these patients provides precise information on the RBC production of the bone marrow following transplantation. Retic donor chimerism levels were &gt;99% for both P1 and P2, 1 month after BMT procedure. P1 and P2 showed stable donor reticulocyte and donor erythroid chimerism levels during the follow-up. On the contrary, P3 presented a different response with 43%, 41% and 5% donor erythroid chimerism 1, 2 and 3 months after BMT, respectively. Retrospectively, this bad response in P3 would have been predicted by low donor reticulocyte chimerism levels (5%, 6% and 0.5% at 1, 2 and 3 months after BMT, respectively). Our erythroid specific chimerism results were also compared to the assessment of chimerism performed on either total white blood cells (WBCs) or lineage specific subpopulations after sorting. Over 18 months after BMT in P1, the correlation between retic chimerism and total WBCs or T lymphocytes (CD3-positive cells) chimerism were not statistically significant (P = 1 and P = 0.833, respectively - Spearman test) (Figure 1). This new tool to monitor BMT outcome to treat SCD shows great precision and potentially a stronger predictive capability than total WBCs or lineage specific chimerism assessed by molecular biology. Our results highlight the importance of analyzing reticulocyte population to better assess BMT efficacy and predict the outcome a few days after the transplant. Its use could also be considered in the context of the various gene therapy strategies currently under development using modified β-globin gene addition or direct mutation correction through CRISPR/Cas9 and homologous recombination system. Figure 1 Figure 1. Disclosures Bencheikh: Innovhem: Current Employment. Bartolucci: Innovhem: Current holder of individual stocks in a privately-held company.

scholarly journals Whole blood transcriptomic analysis reveals PLSCR4 as a potential marker for vaso-occlusive crises in sickle cell disease

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hawra Abdulwahab ◽  
Muna Aljishi ◽  
Ameera Sultan ◽  
Ghada Al-Kafaji ◽  
Kannan Sridharan ◽  
...  
Keyword(s):  
Steady State ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Whole Blood ◽  
Differentially Expressed ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Controls ◽  
Cell Disease ◽  
Blood Disorder ◽  
Potential Biomarker

AbstractSickle cell disease, a common genetic blood disorder, results from a point mutation in the β-globin gene affecting the configuration of hemoglobin, predisposing to painful vaso-occlusive crisis (VOC) and multi-organ dysfunctions. There is a huge variation in the phenotypic expressions of SCD and VOC owing to genetic and environmental factors. This study aimed to characterize the whole blood gene expression profile using Microarray technology in Bahraini patients with SCD determining the differentially expressed genes in steady-state (n = 10) and during VOC (n = 10) in comparison to healthy controls (n = 8). Additionally, the study intended to identify potential genetic marker associated with hemolysis. The analysis identified 2073 and 3363 genes that were dysregulated during steady-state and VOC, respectively, compared to healthy controls. Moreover, 1078 genes were differentially expressed during VOC compared to steady state. The PLSCR4 gene was almost 6-fold up-regulated in microarray, 4-fold in polymerase chain reaction, and a mean protein concentration of 0.856 ng/ml was observed in enzyme-linked immunosorbent assay during VOC compared to steady-state (0.238 ng/ml) (p < 0.01). Amongst these genes, PLSCR4 is involved in erythrocyte membrane deformity thus, predisposing to hemolysis, adhesion, and thrombosis. In conclusion, PLSCR4 may serve as a potential biomarker for VOC and future large-scale validation are recommended.

scholarly journals A Standardized Clinical Flow Adhesion Assay of Whole Blood Adhesion to VCAM-1 Predicts Severe SCD Phenotypes in a 2-Yr Prospective Observational Follow-up of the Original Elipsis Cohort

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3562-3562
Author(s):  
Patrick C. Hines ◽  
Ahmar Urooj Zaidi ◽  
Xiufeng Gao ◽  
Ke Liu ◽  
Muhammad O. Shareef ◽  
...  
Keyword(s):  
Steady State ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Whole Blood ◽  
Hospital Admissions ◽  
Phenotypic Variability ◽  
Acute Chest Syndrome ◽  
Adhesion Assay ◽  
Cell Disease ◽  
Equity Ownership

Sickle cell disease (SCD) is a complex, multi-organ system condition characterized by frequent and unpredictable vaso-occlusive episodes (VOEs) and significant phenotypic variability. Red blood cell (RBC) adhesion contributes to vaso-occlusive pathology, thus we have developed and validated a standardized clinical whole blood flow adhesion assay to VCAM-1 (FA-WB-VCAM) to serve as a clinical biomarker of RBC health in sickle cell disease and other conditions1-4. Blood for the FA-WB-VCAM assay is drawn in sodium citrate tubes and can be stored at 4oC for up to 48hrs. Whole blood samples are perfused through VCAM-1-coated channels and adherent blood cells are quantified manually to generate a clinical adhesion index (cells/mm2). We previously reported longitudinal steady-state FA-WB-VCAM adhesion indices established from every 3 weeks blood sampling over 6 months (mean=368.3 ±198.4 cells/mm2, range=83.50 - 917.0), and the correlation of steady state adhesion indices to a lifetime historical SCD severity index (SCDI) (r=0.5851, p=0.0003) 5,6. The lifetime historical SCDSI was calculated by quantifying the total number of objectively, documentable, vaso-occlusive end-organ events (VEEs), including acute chest syndrome/pneumonia, stroke, priapism, splenic sequestration, hepatic sequestration, and cholelithiasis, indexed over the total years of life (# VEEs/age; range=0.0 to 0.38 in ELIPSIS). The objective of this study was to determine if the FA-WB-VCAM could predict clinical SCD severity prospectively using various metrics of disease severity, including the SCDI over a 2-year period post ELIPSIS. First, we classified study subjects as "severe" or "mild/moderate" adhesion phenotypes defined by mean steady state adhesion indices acquired from every 3 week sampling over 6 months of the ELIPSIS study (severe adhesion phenotype: &gt; 75th percentile, 455.9 cells/mm2; mild/moderate adhesion phenotype: &lt; 75thpercentile). VEEs were verified by retrospective review of medical records, and a SCDSI over the 2-year period following the ELIPSIS study was established. Our data show that individuals with severe adhesive SCD phenotypes experienced significantly more VEEs compared to individuals with low/moderate severe adhesive SCD phenotypes (mean=55.67 ±69.78 compared to mean=17.04 ±20.58 respectively; p=0.01). SCD patients with severe adhesive phenotypes also had more hospital admissions (mean=5.67 ±2.29 compared to mean=2.88 ±3.41, p=0.001), ER visits (mean=36.00 ±63.42 compared to mean=9.20 ±15.65, p=0.02), transfusions (mean=4.33 ±3.74 compared to mean=1.60 ±2.55, p=0.01), acute chest syndrome/pneumonia (mean=1.56 ±0.73 compared to mean=0.20 ±0.65, p&lt;0.001), and priapism (mean=2.56 ±5.57 compared to mean=0.00 ±0.00, p=0.003) when compared to low/moderate adhesive phenotypes. These data suggest that the FA-WB-VCAM assay may serve as a predictive biomarker for impending VEEs, and a monitoring biomarker to assess response to SCD-modifying therapies. Additional studies in a larger prospective cohort are required to definitively establish the clinical utility of the FA-WB-VCAM assay. Disclosures Hines: Functional Fluidics: Equity Ownership. Gao:Functional Fluidics: Equity Ownership. Liu:Functional Fluidics: Employment. White:Functional Fluidics: Equity Ownership.

Analysis Of Hemostatic Characteristics using Thromboelastometry in Adults With Sickle Cell Disease and Controls

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4766-4766
Author(s):  
Maissaa Janbain ◽  
Cindy A. Leissinger ◽  
Rebecca Kruse-Jarres
Keyword(s):  
Steady State ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Whole Blood ◽  
Sickle Cell Trait ◽  
Acute Illness ◽  
Cellular Component ◽  
Healthy Controls ◽  
Cell Disease ◽  
The Impact

Background Vaso-occlusive phenomena and hemolysis are the clinical hallmarks of sickle cell disease (SCD). In addition, pain crisis was identified as the initial clinical manifestation in 61.9% of sickle cell patients who died shortly after hospital admission from thromboembolism and micro vascular thrombi.  Knowing that the vaso-occlusive events may be related to activation of the hemostatic system, and that thromboelastometry (TEM) assesses the functionality of this system from a global standpoint, it will be challenging to characterize the findings in patients with SCD as a way to differentiate their clinical phenotype upon presentation, and to predict the impact of these manifestations on their prognosis, mortality and morbidity. Objective   To characterize the findings of TEM in patients with SCD during periods of steady state and acute illness, to compare these results with those of healthy controls and sickle cell trait (SCT), to compare the findings in whole blood (WB) to plasma (PL) for each category, in a way to analyze the findings in plasma and their applicability in clinical practice as well as to delineate the contribution of the cellular component in whole blood samples. Design  In a cross-sectional study, we obtained TEM and other hemostatic data on 24 adult patients with SCD (16 in steady state and 8 in acute illness); and 13 race and age matched healthy controls (6 with sickle cell trait (SCT) and 7 with no trait). We specifically studied coagulation time (CT) as a function of coagulation factors; clot firmness time (CFT) and alpha angle(α) assessing platelet and fibrinogen function; and maximum clot firmness (MCF) evaluating the mechanical clot quality (plt, fibrinogen and factorXIII) and finally thrombodynamic potential index (TPI) as a function of patient’s global coagulation. Results   Overall, patients with SCD had higher TPI in WB (p=0.23;=0.25) and lower TPI in PL (p<0.0001;=0.47) when compared to controls and SCT respectively. Also, patients with SCD had lower CT (p=0.02), lower CFT (p<0.0001) higher MCF; α and TPI (p<0.0001; =0.051; <0.0001) in whole blood compared to plasma. Sickle cell trait patients had lower CT, CFT, alpha with higher MCF in WB compared to PL. While healthy controls had higher CT; MCF and TPI (p=0.01; <0.0001; <0.0001) and lower CFT, α (p=0.16; <0.0001) in WB compared to PL. Conclusion  Whole blood of SCD patients seems to be hypercoagulable in comparison to WB of controls and SCT. While the plasma of SCD patients was significantly hypocoagulable when compared to PL of healthy controls. Overall, TEG profiles of WB were different than PL. This was more obvious in SCD patients reinforcing the contribution of the cellular component to the pathophysiology of this disease and the possible compensatory hypocoagulable status of the plasma in these patients. Further study of larger and more homogeneous patient groups, is required to adequately assess the clinical utility of TEM in patients with sickle cell disease. Disclosures: Kruse-Jarres: Baxter Healthcare: Consultancy; Bayer HealthCare: Consultancy; Biogen IDEC: Consultancy; Grifols: Consultancy; Kedrion: Consultancy; Novo Nordisk: Consultancy.

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