Red Blood Cell Alloimmunization in Sickle Cell Disease: Advantage of Ethnic Heritage between Donors and Patients in Jeddah, Saudi Arabia

Abstract Introduction/Objective Red blood cell (RBC) transfusion is frequently required for patients with sickle cell disease (SCD). Development of alloantibodies in these patients complicates the blood bank process needed to identify these antibodies and to find compatible RBC units. The rate of alloimmunization has been reported as high as 47% in one study and 34.2% in another study from Eastern region of Saudi Arabia. The purpose of this study was to determine incidence and rate of RBC alloimmunization in the Saudi population in the Western region in SCD. Methods/Case Report A retrospective analysis of the immunohematological and transfusion history of a total of 161 SCD patients was reviewed, of which there 95 males and 66 females. All patients had erythrocytapheresis, ranging from one to 24 full red cell exchange sessions. A total of 490 red cell exchanges were performed and 4,914 units of blood were used. Extended compatibility to RhCcEe and K antigen was performed. Patient who developed alloimmunization to any of RhCcEe and K antigen were matched for Kidd, Duffy and MSN antigens for subsequent RBC requirements. Results (if a Case Study enter NA) The RBC alloimmunization incidence was 18% with a rate of 0.6 antibodies per 100 RBC transfusions. Alloimmunization in females was significantly higher than in the patients. Eighteen (11.2%) female patients demonstrated antibodies as compared to eleven (6.8%) male patients. Twelve patients (7.4%) had a history of at least one alloantibody and 17 (10.6%) had more than one. Antibodies found were directed against E (7.4%), K (5.6%), and D, C, c, S, M, Lea, Jk a, Chido/Rodgers, Fy a. Seven (4.3%) patients also had warm autoantibodies. Conclusion RBC alloimmunization incidence and rate in our study was lower to those reported in less heterogeneous population of donors and patients. Nonetheless, RBC alloimmunization still occurs in patients with SCD, often due to Rh variants or lack of consistency in the application of prophylactic antigen matching between institutions. Therefore, we believe that this rate can still be further reduced if all centers in the region establish transfusion programs to include at least RhCcEe and K phenotypic compatibility and communication mechanisms between major treating centers and transfusion centers in smaller cities to minimize the risks of exposing the patient to different RhCcEe and K phenotype and of developing RBC alloimmunization.

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Clinical Effects of Chronic Red Blood Cell Exchange and Different Types of Red Cell Concentrates in Patients with Sickle Cell Disease

Blood ◽

10.1182/blood.v112.11.4823.4823 ◽

2008 ◽

Vol 112 (11) ◽

pp. 4823-4823

Author(s):

Sergio Cabibbo ◽

Agostino Antolino ◽

Giovanni Garozzo ◽

Carmelo Fidone ◽

Pietro Bonomo

Keyword(s):

Sickle Cell Disease ◽

Blood Cell ◽

Iron Overload ◽

Sickle Cell ◽

Red Blood Cell ◽

Whole Blood ◽

Clinical Effects ◽

Red Cell ◽

Blood Components ◽

Cell Disease

Abstract For patients with severe SCD not eligible for hydroxyurea, two major therapeutic options are currently available: blood transfusion, and bone marrow transplantation. Either urgent or chronic red blood cell transfusion therapy, is widely used in the management of SCD but determines a progressive increase of ferritin level and is also limited by the development of antibodies to red cell antigens. The introduction of chronic red blood cell exchange and prestorage filtration to remove leucocytes and the use of techniques for multicomponent donation could be a good solutions. Thus, the aims of our studies were to evaluate the clinical effects of the different blood components in terms of annual transfusion needs and the intervals between transfusion, moreover we evaluated the efficacy of chronic red blood cell exchange (manual or automatic with cell separator) in preventing SCD complications and limiting iron overload. In our center we follow 78 patients affected by Sickle Cell Disease. We selected 36 patients occasionally treated with urgent red blood cell exchange because they had less than 2 complications/Year, and 42 patients regularly treated with chronic red blood cell exchange because they had more than 2 complications/Year with Hospital Admission. Moreover among these we selected 10 patients for fulfilling the criteria of continuous treatment at the Centre for at least 48 months with no interruptions, even sporadic and absolute transfusion dependency. All 10 patients were evaluated for a period of 4 years, during which two different systems of producing RCC were used. In the second two the patients were transfused with RCC obtained from filtering whole blood prestorage or with RCC from apheresis filtered prestorage. These products differed from those used in the preceding two years, during which the leucodepletion was obtained by bed-side filtration For all the patients we performed 782 automatic red blood cell exchanges and 4421 units of RCC were transfused. The exchange procedures were extremely well-tolerated by the patients and adverse effects were limited to symptoms of hypocalcaemia during automatic red blood cell exchange with cell separator. After every red blood cell exchange we obtained HbS level < 30%. The10 patients selected received respectively a mean of 6.9 and 6.1 units of RBCs exchanged per automatic procedure, in the first two years and in the second two years. Alloantibody developed in 14 patients but only 2 clinically significant and about the observed frequency of transfusion reactions it was very low. All patients treated with chronic red blood cell exchange had an improvement of the quality of life with a reduced number of complications/year (<2/year) and good compliance and moreover patients had limited iron overload making chelating therapy easier. In conclusion this study was focused on the most suitable characteristics of blood components for use in sickle cell disease patients and the choice of systematically adopting prestorage filtration of whole blood, enabled us to have RCC with a higher Hb concentration than standard. Moreover chronic manual or automatic red blood cell exchange as an alternative approach to simple long-term RBC transfusions give many advantages by being more rapid and tolerable as well as clinically safe and effective and minimize the development of iron overload especially when procedure was carried out with an automatic apparatus. To note that the clinical advantages for patients derived from good selection of the donor and good practices in the production of the blood components

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Outcomes of Red Cell Exchange in Pregnant Patients with Sickle Cell Disease: A Case Series

Blood ◽

10.1182/blood-2020-139892 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 22-22

Author(s):

Mahammed Khan Suheb ◽

Omar Abughanimeh ◽

Steven Ebers ◽

Julie Eclov ◽

Aleh Bobr ◽

...

Keyword(s):

Sickle Cell Disease ◽

Blood Cell ◽

Emergency Room ◽

Sickle Cell ◽

Red Blood Cell ◽

Red Cell ◽

Cell Disease ◽

Modest Improvement ◽

Exchange Program ◽

The Third

Background: Pregnant patients with sickle cell disease (SCD) have higher morbidity compared to patients without SCD. SCD during pregnancy can increase the risk of fetal and obstetrical complications including preterm birth, preeclampsia, and others. Moreover, during pregnancy SCD can become more severe resulting in more sickle cell vasoocclusive crisis. Prophylactic transfusion during pregnancy has been used in practice to reduce sickle cell pain crisis since hydroxyurea is contraindicated during pregnancy. However, using prophylactic red blood cell exchange (RBCX) has been a controversial topic. In this study, we aim to evaluate the outcomes of red blood cell exchange in pregnant patients with SCD Methods: This is a retrospective study. We evaluated the charts of three pregnant patients who were enrolled in the chronic RBCX program at the University of Nebraska Medical Center at the time of their pregnancy. Data was collected to assess the sickle cell disease related complications during pregnancy, outcomes of pregnancy, and safety of the red blood cell exchange. Results: A total of 19 exchange procedures were performed for three pregnant patients while being enrolled in the chronic red blood cell exchange program. Patients demographic is summarized in table 1. The indication for enrollment in the red cell exchange program were recurrent vasooclussive crisis in patient 1 and 3, avascular necrosis in patient 2. The pregnancies were uncomplicated except for preeclampsia in the third patient resulting on early delivery. Overall, the three patients had less frequent visits to the emergency room for sickle cell related complications after starting apheresis and during pregnancy (Figure 1). We believe that the modest improvement that was noticed for the third patient was due to late enrollment in the exchange transfusion program and her older age compared to the two other patients Conclusion: Our study shows that red blood cell exchange for SCD patients during pregnancy can be safe, feasible, and can reduce the visits to the emergency room due to SCD related complication. Further larger studies are warranted to confirm this. Disclosures Gundabolu: BioMarin:Consultancy;Bristol Myers Squibb pharmaceuticals:Consultancy.

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Assessment of Average Hematocrit of Red Cell Units for Erythrocytapheresis Procedure in Sickle Cell Disease

Blood ◽

10.1182/blood-2021-148842 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 4285-4285

Author(s):

Veronica Cook ◽

Teresa Munson ◽

Elpidio Pena ◽

Ashok Raj

Keyword(s):

Sickle Cell Disease ◽

Blood Cell ◽

Sickle Cell ◽

Red Blood Cell ◽

Small Sample ◽

Red Cells ◽

Red Cell ◽

Limited Data ◽

Cell Disease ◽

Consensus Report

Abstract Background: Erythrocytapheresis, or red blood cell exchange (RCE) is a non-invasive procedure in which a patient's erythrocytes are removed from the bloodstream while being replaced with erythrocytes from blood donors. RCE is commonly used as a transfusion technique in patients with sickle cell disease (SCD) to help treat and prevent complications associated with sickling of erythrocytes and iron overload. The AABB consensus report (1) outlines the procedural guidelines for RCE including appropriate indications and ideal forms of vascular access. However, the guidelines make no recommendation for determining the hematocrit (Hct) of the red cell bags for the procedure. Institutions take several different approaches to determine how many red cell units to exchange. The number of units needed depends on the volume and Hct of the individual units as well as the patient's pre-procedure Hct and HbS levels, height, weight, and the desired HbS and Hct targets. Red cell units are routinely labeled with volume, but are not generally labeled with Hct. The AABB consensus report (1) states that some institutions use an estimated Hct of 56% to 57% for each unit. The report rationalizes the use of an estimated Hct for input for the RCE, by citing the approximated Hct of bags of red cells (55% to 60%) with additive solution produced from whole blood donation, based on limited data. The goal of our study was to determine the average Hct on the red cell units used for RCE. Methods: This study used a retrospective chart review to investigate the Hct of red cell units during a RCE in a calendar year. Our institution uses pre-storage leuko-reduced red blood cells units in citrate phosphate dextrose adenine (CPDA-1) and adsol preservative (AS-1), which are 21 days old or less for RCE. The average Hct of the bags of red cells infused during the procedure was determined by accessing each bag for a small sample of blood to determine the Hct. Data was excluded if the patient did not meet standard weight requirements (> 30 kg) or required additional treatment protocols including the use of washed cells or machine priming. Results: A total of 297 encounters were recorded for 30 different patients. A total of 1953 bags (approximately 517 liters of red cell units in volume) were administered. Data from the encounters were used to calculate measures of central tendency. The average calculated Hct for each encounter was 63.3%, with a median and mode Hct being 63% and 62%. The range of Hct from the bags was 54.6% to 72.9%. The average Hct of the bags ranged from 60.6% (in March) to 64.8 % (in July). Conclusions: Our study suggests a higher average Hct of transfused red cell units than stated in the AABB consensus report (1), which was based on limited data. Our findings indicate that a standardized average of 63.3%, would be appropriate for our institution. Conversely, our findings also signify that the standardized average Hct must be determined in each institution prior to their application for RCE. However, our data also reveals that it is possible to subject patients to estimates as far as 9.7% above and 9.6 % below the true average Hct of the red cell bags used. The process of determination of Hct for each of the red cell units increases the time of pre-service activities, laboratory costs, and the overall infusion center time for the patients leading to higher costs per infusion. Consequently, using a standardized average of the Hct would result in cost savings. We have therefore adopted the practice of using the standardized average of Hct of 63.3% for RCE in our patients. Reference: 1. Biller E, Zhao Y, Berg M, Boggio L, Capocelli KE, Fang DC, Koepsell S, Music-Aplenc L, Pham HP, Treml A, Weiss J, Wool G, Baron BW. Red blood cell exchange in patients with sickle cell disease-indications and management: a review and consensus report by the therapeutic apheresis subsection of the AABB. 2018 Aug;58(8):1965-1972. doi: 10.1111/trf.14806 Disclosures Munson: Terumo Medical Corporation: Consultancy, Honoraria, Speakers Bureau. Raj: Terumo Medical Corporation: Honoraria, Speakers Bureau; Global biotherapeutics: Speakers Bureau; Forma therapeutics: Consultancy.

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End-Alveolar Carbon Monoxide As a Measure of Erythrocyte Survival and Hemolytic Severity in Sickle Cell Disease

Blood ◽

10.1182/blood.v124.21.2696.2696 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2696-2696

Author(s):

Caterina P. Minniti ◽

John H. Baird ◽

Dihua Xu ◽

Laurel Mendelsohn ◽

Rehan Saiyed ◽

...

Keyword(s):

Sickle Cell Disease ◽

Blood Cell ◽

Life Span ◽

Sickle Cell ◽

Red Blood Cell ◽

Adult Patients ◽

Red Cell ◽

Cell Disease ◽

Indirect Bilirubin ◽

Cell Lifespan

Abstract Introduction: In sickle cell disease, polymerization of sickle hemoglobin gives rise to changes in the integrity and viability of the erythrocyte, leading to both extravascular and intravascular hemolysis and shortened life-span. Current gold standard techniques to estimate RBC survival require that a label be placed on the cells that can be followed while the RBCs age in the circulation. These studies are infrequently employed in practice, due to the need for multiple blood draws and an extended period of observation (6 weeks) in order to obtain the necessary time points. Endogenous CO is a technique that has been used in multiple studies to assess RBC survival, based upon the principal that virtually all CO produced in human beings results from cleavage of the α-methene bond of heme and is completely excreted via the lungs. Because RBC destruction accounts for approximately 80% of heme turnover in the body, endogenous CO production can be used as a quantitative indicator of RBC life span. Furne has reported on the development of a simple, rapid, and noninvasive method for determining RBC life span based on gas chromatography measurement of exhaled alveolar CO (EACO) concentration immediately upon awakening corrected for atmospheric CO, as determined with a device that simulates the body's equilibration with CO. We set up to investigate the use of early morning end-alveolar CO (EACO) concentration as a quantitative measure of RBC life span and correlate it to indirect measurements of hemolytic rate in subjects with sickle cell disease. Material and methods: EACO was measured within 24 hours of breath collection in 67 SCD adult patients (67 HbSS, 4 HbSC and 1 HbSb-Thalassemia) and 14 HbAA race matched controls on an Ametrek TA 7000 Gas Purity Monitor. Subjects were at steady state, at least 30 days from transfusion or acute exacerbations. Breath samples were collected immediately upon awakening the same day as blood sampling for additional tests. EACO groups were compared using the Mann-Whitney test. EACO values were used to calculate the red blood cell lifespan by the method of Furne (PMID 12878986), using the calculation: RBC survival (days) = 1,380 · [Hb]/EACO. Correlation analyses are reported using Pearson's correlation coefficient. The statistical significance was set at a two-side p < .05. Analyses were performed with R version 2.13.1 (2011-07-08). Results: EACO was nearly four-fold higher in patients than controls (median 2.25 vs. 0.58 ppm, p<.0001, figure). In patients with SCD, unadjusted EACO values were correlated with %HbS (p<.01), indirect markers of hemolysis: absolute reticulocyte count (p<.02), and percentage of reticulocytes (p<.01), indirect bilirubin (p<.001), and negatively with plasma nitrite (p<.02). EACO-derived red blood cell lifespan correlated negatively with LDH (p<.04), hematocrit (p<.01), hemoglobin (p<.06) indirect bilirubin (p<.01), absolute and percent reticulocyte counts (p<.01), AST (p<.01), and %HbS (p<.01). Conclusions: Our results confirm the usefulness of exhaled CO measurement as a marker of hemolysis and red cell survival and in substantial, prospective cohort of adult patients with SCD, confirming and considerably extending results of other investigators. EACO-derived RBC survival can be used to update estimates from Crosby in 1955 regarding the proportion of overall hemolysis falling into the extravascular and intravascular categories, the latter related to oxidative stress and scavenging of nitric oxide. This assay may be a useful biomarker in clinical trials of therapeutic interventions aimed at improving red cell life-span in SCD and other hemolytic anemias. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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Red Blood Cell Alloimmunization in Sickle Cell Disease Patients in Jeddah, Saudi Arabia: A Pilot Study.

Journal of King Abdulaziz University-Medical Sciences ◽

10.4197/med.22-3.5 ◽

2015 ◽

Vol 22 (3) ◽

pp. 34-40

Author(s):

Abdulrahman S. Alboog ◽

Taher M. Tayeb ◽

Mohammed O. Alsager ◽

Salwa A. AlNajjar ◽

Ghazi A. Damanhouri ◽

...

Keyword(s):

Saudi Arabia ◽

Sickle Cell Disease ◽

Blood Cell ◽

Red Blood Cells ◽

Sickle Cell ◽

Red Blood Cell ◽

Blood Cells ◽

University Hospital ◽

Cell Disease ◽

Significant Difference

The treatment of patients with sickle cell disease frequently requires transfusion of red blood cells. Complications due to alloimmunization of red blood cells antigen remain a major risk as a post transfusion effect. The objective of this study is to determine the frequency of red cell alloimmunization in Jeddah, Saudi Arabia. A retrospective cross-section study of sickle cell disease patients at King Abdulaziz University Hospital between 2012 and 2013 was performed. Demographic characteristics and transfusion history was recorded. Blood samples were analyzed for alloimmunization using immunohematological technique. A total of 234 sickle cell patients were analyzed, of which 30 (12.8%) showed alloantibodies. A total of 43 alloantibodies were found out of which 28 belonged to Rh group, eight belonged to Kell while three belonged to MNS group. Demographic and transfusion characteristics were analyzed between alloimmunized and nonalloimmunized sickle cell disease patients. The rate of alloimmunization in Jeddah, Saudi Arabia was 12.8%. There was significant difference observed between alloantibodies detection between transfused patients compared to non-transfused patients. The consequences of red blood cell alloimmunization are highly significant and therefore immune hematological testing is highly recommended.

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FCGR2B B2.4 Haplotype Predicts Increased Risk of Red Blood Cell Alloimmunization in Sickle Cell Disease Patients

Blood ◽

10.1182/blood-2018-99-113896 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1255-1255

Author(s):

Abel Costa Neto ◽

Flávia Leite Santos ◽

Ingrid Helena Ribeiro ◽

Valeria Brito Oliveira ◽

Marcia Regina Dezan ◽

...

Keyword(s):

Logistic Regression ◽

Sickle Cell Disease ◽

Blood Cell ◽

Sickle Cell ◽

Red Blood Cell ◽

Promoter Region ◽

Cell Disease ◽

Increased Risk ◽

Lifetime Number ◽

History Of

Abstract Introduction: Red blood cell (RBC) alloimmunization is an important transfusion complication which is very prevalent among patients with sickle cell disease (SCD). Only part of patients is able to develop alloantibodies following antigen-mismatched transfusions, named the 'immune responders', who should be prospectively transfused with antigen-matched RBC units, comprising the most immunogenic erythrocyte antigens. Auto-immune diseases are a known risk factor for RBC alloimmunization, suggesting that auto-immunity and post-transfusion alloantibody development happen through similar physiopathological pathways. In this context, polymorphisms in FCGR2B gene have already been associated with several auto-immune disorders and, hypothetically, could be associated with RBC alloimmunization and help to identify the 'immune responders' in transfusion practice. Methods: In this case-control study, we enrolled 277 transfused SCD patients with retrospective data on alloimmunization status and transfusion exposure from two Brazilian centers. DNA samples (collected from March, 2017 to June, 2018) were extracted from whole blood samples using commercial kits (PureLink™ Genomic DNA®, Invitrogen, CA), and used for PCR amplification of promoter region of FCGR2B gene containing both -386G/C and -120T/A single nucleotide polymorphisms (SNPs) using gene-specific primer. SNPs of the FCGR2B were genotyped by direct Sanger sequencing (ABI3730XL, Applied Biosystems, CA). Cases had a positive history of alloimmunization with a clinically significant alloantibody and a minimum transfusion exposure of 1 RBC unit. Controls had a negative history of alloimmunization and having received ≥ 2 RBC units. Patients with autoimmune diseases or poor quality of DNA were excluded. Unadjusted and adjusted analyses were conducted by using Logistic Regression models to determine the association of covariates with binary outcome. Since the assumption of linearity in the logit was not supported, continuous covariates were categorized based on optimum cut-off point derived from ROC analysis. All statistical analyses were performed using SAS University Edition. A p-value of <0.05 was considered to be statistically significant. Results: A total of 237 patients met the eligibility criteria, 121 cases (alloimmunized) and 117 controls (non-alloimmunized). Majority of patients were female in cases (61%) and male in controls (86%), with mean age of 27.9 years (SD 15.3). Table 1 list the characteristics between the groups. RBC alloimmunization was associated with female sex (p<0.001), lifetime number of RBC units transfused (p=0.002) and FCGR2B 120T/A SNP (p=0.031). No statistically differences in the allele frequency of c.386C were observed between groups (p=0.602). FCGR2B -386G/C and -120T/A SNPs were in intense linkage disequilibrium. Three haplotypes of promoter region were identified as 2B.1 (-386G-120T), 2B.2 (-386C-120T) and 2B.4 (-386C-120A) with statistical significance (p=0.045). Logistic regression model was performed to assess the effects of age, gender, lifetime number of RBC units transfused and FCGR2B 2B.4 haplotype on the likelihood of RBC alloimmunization in patients with SCD. The analysis identified that female sex (OR 10.03, CI95% 5.16-19.49; p<0.001) and FCGR2B 2B.4 haplotype (OR 4.55, CI95% 1.11-18.65; p=0.035) predict increased risk of RBC alloimmunization in SCD patients as show in Table 2. Conclusions: SCD patients with the FCGR2B 2B.4 haplotype had over a 4-fold higher risk for RBC alloimmunization in comparison with patients without this haplotype and probably may be helpful to identify the 'immune responders'. The presence of FCGR2B 2B.4 haplotype have been associated with increased expression of this inhibitory Fc gamma receptor in immune system cells, that was strongly associated with capacity of immune tolerance, regulating the development of antibodies. Future studies are needed to understand more about the functional and immune mechanism behind alloimmunization in SCD patients and ultimately improve our current preventive strategies. Disclosures No relevant conflicts of interest to declare.

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Clinical and Genetic Variability of Red Blood Cell Hemolysis in Sickle Cell Anemia

Blood ◽

10.1182/blood.v118.21.1077.1077 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1077-1077

Author(s):

Jacqueline N Milton ◽

Paola Sebastiani ◽

Yingze Zhang ◽

Mehdi Nouraie ◽

Janet Lee ◽

...

Keyword(s):

Sickle Cell Disease ◽

Blood Cell ◽

Sickle Cell ◽

Red Blood Cell ◽

Globin Gene ◽

Red Cell ◽

Cell Disease ◽

Intravascular Hemolysis ◽

Plasma Hemoglobin ◽

Cell Storage

Abstract Abstract 1077 Intravascular hemolysis is an important pathological mechanism underlying some complications of sickle cell disease and other hemolytic anemias. Hemolysis contributes to endothelial dysfunction, pulmonary and systemic vasculopathy, and platelet and hemostatic activation via nitric oxide catabolism by plasma hemoglobin and arginine catabolism by red blood cell arginase. Little is known about the molecular mechanisms of hemolysis and how the propensity of erythrocytes to hemolyze is modulated. Hemoglobin F concentration and the presence of ∝ thalassemia affect the level of hemolysis but it is likely that other genes and their products are also important. We hypothesize that genetic variation, much of which is outside the β-globin gene-like cluster, underlies the susceptibility of erythrocytes to hemolyze in response to diverse disease stressors. We first characterized hemolysis by creating a principal component analysis (PCA) of age-adjusted values for LDH, AST, reticulocyte count and total bilirubin, but not hemoglobin concentration, to develop a hemolytic component that reflects shared variability among markers. The development of such a component helps to resolve the problem of dealing with correlated predictors in multivariate analyses and confounding variables such as site, and it permits for adjustment for the degree of anemia. To validate the PCA, we measured the plasma hemoglobin levels and red cell microparticle levels in the first and fourth quartile of PCA intensity of hemolysis in 118 HbS-only patients without detectable HbA, from the Walk-PHASST cohort We observed a highly significant increase in plasma hemoglobin (p<0.0001) and red cell microparticles (p=0.0004) based on PCA quartile. Despite the small sample size of this validating cohort we reproduced significant associations between high hemolytic rate and the subphentypes of low arterial oxygen saturation, high pulse pressure, leg ulcers, TRV, high NT-proBNP levels, and low 6-minute walk test distance. More patients with ∝ thalassemia and more females were present in the lower hemolytic index quartile (p=0.006). The hemolytic index and its individual components were then used as phenotypes in genome-wide association studies (GWAS) in the CSSCD (Cooperative Study of Sickle Cell Disease) and walk-PHaSST cohorts to discover novel genes that might be associated with hemolysis. As further validation of our approach using PCA stratification, patients in the quartile with the lowest hemolytic index from the CSSCD also had a much higher prevalence of ∝ thalassemia than patients within the highest quartile of hemolytic index (p=2.2E-16). We first examined 1117 cases from the CSSCD and found 303 SNPs, 265 with a MAF >0.05, that reached a threshold of significance of p<5E-4. For replication, we examined these SNPs in the Walk-PHASST cohort. Eight SNPs replicated with the same effects in a GWAS in 449 subjects from Walk-PHAAST and p-value<0.01. Of the 8 SNPs that replicated, 4 SNPs were in olfactory receptor (OR) genes on chromosome (chr) 11p; OR51L2 (rs7948471, rs7938426. rs1391617), and OR51L1 (rs2445284). Several of these SNPs were also associated with HbF in previous GWAS analyses. Polymorphisms in the OR gene cluster upstream of HBG might modulate HbF levels by altering chromatin structure within the HBB globin gene-like cluster. One SNP in an intron of NPRL3 (rs7203566) on chr16p is ∼34 kb upstream from a SNP causing ∝ thalassemia. In CSSCD cases there was an association of SNPs in NPRL3 with reticulocytes (p=5.1E-0006) and LDH (p=0.0003). In silico analysis did not predict any function for this SNP. Genetic studies to discover new biologic modifiers of hemolysis will help to identify critical molecular determinants of hemolysis for functional studies, to develop new disease severity biomarkers, and to suggest candidate therapies for some common human diseases with intravascular hemolysis. We anticipate that our studies will identify genetic variants enriched in the African-American population primarily determined by the evolved human response to endemic malaria infection. These studies are expected to broadly impact many human diseases and blood banking by providing genomic markers of susceptibility to hemolytic anemia, red cell storage stability and transfusion risk, and insights into novel strategies to reduce anemia and to enhance red blood cell storage and post-transfusion erythrocyte recovery. Disclosures: Gladwin: Patents filed related to treating hemolysis.: Patents & Royalties.

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Drugs for preventing red blood cell dehydration in people with sickle cell disease

10.1002/14651858.cd003426 ◽

2002 ◽

Cited By ~ 13

Author(s):

C Riddington ◽

L De Franceschi

Keyword(s):

Sickle Cell Disease ◽

Blood Cell ◽

Sickle Cell ◽

Red Blood Cell ◽

Cell Disease ◽

Cell Dehydration

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Effects of Genotypes and Treatment on Oxygenscan Parameters in Sickle Cell Disease

Cells ◽

10.3390/cells10040811 ◽

2021 ◽

Vol 10 (4) ◽

pp. 811

Author(s):

Camille Boisson ◽

Minke A. E. Rab ◽

Elie Nader ◽

Céline Renoux ◽

Celeste Kanne ◽

...

Keyword(s):

Steady State ◽

Sickle Cell Disease ◽

Blood Cell ◽

Sickle Cell ◽

Red Blood Cell ◽

Cell Disease ◽

Oxygen Gradient ◽

Acute Complication ◽

Adults And Children ◽

The Difference

(1) Background: The aim of the present study was to compare oxygen gradient ektacytometry parameters between sickle cell patients of different genotypes (SS, SC, and S/β+) or under different treatments (hydroxyurea or chronic red blood cell exchange). (2) Methods: Oxygen gradient ektacytometry was performed in 167 adults and children at steady state. In addition, five SS patients had oxygenscan measurements at steady state and during an acute complication requiring hospitalization. (3) Results: Red blood cell (RBC) deformability upon deoxygenation (EImin) and in normoxia (EImax) was increased, and the susceptibility of RBC to sickle upon deoxygenation was decreased in SC patients when compared to untreated SS patients older than 5 years old. SS patients under chronic red blood cell exchange had higher EImin and EImax and lower susceptibility of RBC to sickle upon deoxygenation compared to untreated SS patients, SS patients younger than 5 years old, and hydroxyurea-treated SS and SC patients. The susceptibility of RBC to sickle upon deoxygenation was increased in the five SS patients during acute complication compared to steady state, although the difference between steady state and acute complication was variable from one patient to another. (4) Conclusions: The present study demonstrates that oxygen gradient ektacytometry parameters are affected by sickle cell disease (SCD) genotype and treatment.

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Microfluidic electrical impedance assessment of red blood cell mediated microvascular occlusion

Lab on a Chip ◽

10.1039/d0lc01133a ◽

2021 ◽

Author(s):

Yuncheng Man ◽

Debnath Maji ◽

Ran An ◽

Sanjay Ahuja ◽

Jane A Little ◽

...

Keyword(s):

Sickle Cell Disease ◽

Blood Cell ◽

Red Blood Cells ◽

Sickle Cell ◽

Red Blood Cell ◽

Blood Cells ◽

Electrical Impedance ◽

Cell Disease ◽

Blood Disorders

Alterations in the deformability of red blood cells (RBCs), occurring in hemolytic blood disorders such as sickle cell disease (SCD), contributes to vaso-occlusion and disease pathophysiology. However, there are few...

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