Occurrence Of Acute Chest Syndrome Research Articles

Resolvin-D1 (RvD1) and Its Association with Markers of Inflammation, Endothelial Activation, Hemolysis and Clinical Correlates in Children with Sickle Cell Disease (SCD)

Introduction: Sickle Cell Disease (SCD) is an inflammatory and vaso-occlusive pathology. Multiple lipid mediators: resolvins, protectins and maresins, collectively known as Specialized Pro-resolving Mediators (SPMs), that are biosynthesized from Omega-3-PolyUnsaturated Fatty Acids (O3PUFAs), docosahexaenoic acid and eicosapentaenoic acid, appear to play a role in the resolution of inflammation. In a recent study, we have documented the presence of SPMs including Resolvin-D1 (RvD1), 17R-RvD3, and their pathway markers in plasma from both children with SCD and age-and race-matched controls with a significant increase in RvD1 levels noted in plasma from children with SCD. In an SCD mouse model exposed to hypoxia/reoxygenation, a previous study has shown that oral administration of 17R-RvD1, the longer acting isomer of RvD1, promotes resolution of SCD-associated inflammation and tissue damage. Objectives: We assessed whether there were any associations in children with SCD between baseline plasma levels of RvD1 and either markers of inflammation, endothelial activation and hemolysis or SCD-related clinical correlates. Methods: Multiplex assays were employed to assess endothelial activation markers (soluble adhesion molecules VCAM-1, ICAM-1 and E-selectin), and inflammatory cytokines (IL-1β, IL-4, IL-6, IL-10, TNF-α and CRP) in plasma. A 3-year retrospective review of individual SCD patient records was performed, and the number of painful episodes of vaso-occlusion or VOC, including those complicated by the occurrence of acute chest syndrome (ACS) were recorded. Total cumulative painful episodes over a 3-year period were included in the analysis. Spearman Rank Correlation was employed to assess the association between two variables. Results: Consistent with the published results, levels of endothelial activation markers (soluble VCAM-1 and soluble E-selectin), cytokines (IL-4, IL-6 and TNF-α), CRP and LDH were increased in SCD plasma compared to controls (Table-1). No significant associations were found in SCD between RvD1 or other lipid mediators and markers of endothelial activation or inflammation (Table-2). However, there were two significant associations noted between 5-HEPE and IL-1β, and between 12-HETE and IL-6. Plasma levels of the hemolytic marker LDH positively correlated with PGE2, TxB2, 7-HDHA, 5-HEPE and 5-HETE (Table-2). Review of medical history revealed 33 of 45 subjects (73%) had at least one VOC episode, and 17 (38%) had at least one ACS episode in the past 3 years. Subjects who had at least one ACS episode in the past 3 years also reported at least one VOC episode during the same period. There was no statistically significant difference in the RvD1 level by VOC [median RvD1 (ng/ml) of 0.056 in VOC -ve sub-group (n=12) vs 0.084 in VOC +ve sub-group (n=33), p=0.748] or ACS history [median RvD1 (ng/ml) of 0.060 in ACS -ve sub-group (n=28) vs 0.104 in ACS +ve sub-group (n=17), p=0.256]. There was no statistically significant association between levels of RvD1 and the total number of VOC/ACS in the past 3 years (correlation coefficient = -0.06, p=0.694). Summary and Conclusions: Because of the documented pro-resolving and anti-inflammatory effects of orally administered 17R-RvD1 in a mouse model of SCD, and elevated basal plasma levels of RvD1 in children with SCD, we investigated whether endogenous RvD1 provides protection against inflammation and clinical complications in SCD children. Other lipid mediators, which were synthesized from O3PUFAs and arachidonic acid, present in increased levels in SCD plasma and potentially involved in modulation of inflammation were also included in the analysis. Unlike in SCD mouse model in which exogenous RvD1 exerted anti-inflammatory effect in ex-vivo experiments and orally administered 17R-RvD1 promoted resolution of inflammation and down-regulated adhesion molecule expression and cytokine production, endogenous RvD1 did not show any significant association with markers of inflammation and endothelial activation or clinical correlates in a small group of SCD children under healthy condition. No significant findings were noted with other lipid mediators. Whether these lipid mediators modulate inflammation during crisis, pre- or post-crisis clinical conditions and whether their production is different during these clinical conditions compared to steady state healthy condition require further investigation.

PI-04: OXYGEN GRADIENT EKTACYTOMETRY-DERIVED BIOMARKERS ARE ASSOCIATED WITH THE OCCURRENCE OF ACUTE COMPLICATIONS IN SICKLE CELL DISEASE

Purpose: Sickle cell disease (SCD) is a monogenetic disorder with a highly complex pathophysiology. There is an unmet need for robust reproducible biomarkers that can assess red blood cell (RBC) function and predict disease severity and complications. Materials and methods: In this study, we investigated the association between oxygen gradient ektacytometry-derived biomarkers, and blood viscosity with incidence of major (acute) SCD-related complications. Oxygen gradient ektacytometry measures RBC deformability continuously while the sample is gradually deoxygenated and subsequently reoxygenated, and identifies the oxygen tension at which sickling occurs. We examined associations between the occurrence of acute chest syndrome, cerebral infarction and vaso-occlusive crisis (VOC) and known biomarkers such as fetal hemoglobin, blood viscosity as well as exploratory oxygen gradient ektacytometry-derived biomarkers in an adult cohort of 50 individuals with SCD (HbSS or HbS/βo-thalassemia) and a pediatric cohort consisting of 177 children with SCD (HbSS or HbS/βo-thalassemia). A substantial number of subjects were on hydroxyurea therapy (64% of adults and 89% of children). Subjects that received a blood transfusion less than three months prior to measurements were excluded from the study. A logistic regression analysis was performed; odds ratios were adjusted for age and hydroxyurea therapy. Results: In the adult cohort, for every 10 mmHg increase in Point of Sickling (PoS, the pO2 tension where RBCs start to sickle, reflecting sickling tendency) the likelihood of >1 acute complication increased; the adjusted odds ratio (aOR) was 3.00 (p=0.015). For every 0.1 increase in EImax (reflecting RBC deformability at normoxia), the aOR was 0.33 (p=0.035, Table 1). In the pediatric cohort, for every 10 mmHg increase in PoS, the likelihood of >1 acute complication increased; the aOR was 1.65 (p=0.006). For every 0.1 increase in EImin (reflecting RBC deformability at hypoxia), the aOR was 0.50 (p=0.007). Fetal hemoglobin and blood viscosity levels were not associated with likelihood of multiple acute complications. However, fetal hemoglobin was associated with reduced likelihood of VOC in adults (aOR of 0.32 for every 10% increment, p=0.010) but not in children (aOR of 0.68, p=0.231, data not shown). In the adult cohort higher EImax was associated with reduced likelihood of VOC (aOR 0.31, p=0.029). There was a trend found for an association between higher PoS and greater likelihood of VOC (aOR 2.22, p=0.050), and no association for EImin. In the pediatric cohort only EImin was associated with VOC (aOR 0.68, p=0.036). Conclusion: These findings indicate that oxygen gradient ektacytometry generates novel clinically relevant biomarkers and provide a rationale for further development of these biomarkers in the evaluation of novel therapies, as part of clinical care, or clinical trial endpoints. In particular, in assessment of treatment strategies that do not target HbF induction, such as pyruvate kinase activators, voxelotor and l-glutamin, oxygen gradient ektacytometry can generate relevant biomarkers.The authors do not declare any conflict of interest

Identification of Biomarkers That Are Associated with Clinical Complications of Hemoglobin SC Disease and Sickle Cell Anemia

Introduction: Sickle cell disease (SCD) is an umbrella term used to describe inherited anemias that originate from a mutation in HBB, the gene coding for β-globin, that causes the formation of the abnormal hemoglobin S (HbS). The two most common genotypes are HbSS, termed sickle cell anemia (SCA) and HbSC, termed hemoglobin SC disease. Due to the higher prevalence and more severe clinical symptoms in SCA, attention is focused on this latter group of patients. Patients with HbSC disease who report significant SCD related symptoms are treated largely the same as SCA patients, despite differences in disease pathophysiology.Objective: To evaluate rheological differences in red blood cells (RBC) and whole blood from individuals with SCA and HbSC, and examine for associations with clinical complications.Methods: We analyzed an adult (n=30) and pediatric cohort (n=226) of SCA and HbSC individuals. Blood samples were evaluated for percent dense red blood cells (% DRBC), whole blood viscosity, and several ektacytometry-derived parameters, such as the cell membrane stability test, osmotic gradient ektacytometry and Point of Sickling (PoS): an oxygen gradient ektacytometry-derived biomarker that depicts the oxygen tension at which sickling is initiated. Subsequently, we assessed in the pediatric cohort (189 SCA and 37 HbSC individuals) if PoS, dense RBCs or blood viscosity are associated with clinical complications.Results: In particular (micro)dense RBCs (Figure 1A and B), blood viscosity (Figure 1C) and point of sickling (PoS, Figure 1D-F), are notably different in HbSC disease compared to SCA. In SCA, PoS was associated with occurrence of acute chest syndrome (ACS, for every 10mmHg increase OR 1.84, p<0.0001, adjusted OR 1.67, p=0.002), but no such association was found in children with HbSC. In contrast, we found an association of blood viscosity and ACS (OR 9.3, p=0.012; adjusted OR 13.5, p=0.015) in HbSC children, while we found no such association in SCA. No significant association of micro dense RBCs was found in SCA or HbSC children.Conclusion: We found that associations between PoS and ACS found in SCA were not found in HbSC. Instead, in HbSC ACS was associated with higher whole blood viscosity. We therefore conclude that sickling is a key factor in the pathophysiology of SCA, whereas in HbSC disease blood viscosity might play a crucial role in development of certain complications like ACS. This study suggests that complications in SCA and HbSC disease are driven by different aspects of blood abnormalities, and may warrant a distinct treatment approach. [Display omitted] DisclosuresRab: Axcella Health: Research Funding; Agios Pharmaceuticals: Research Funding. Schutgens: Shire/Takeda: Research Funding; Pfizer: Research Funding; OctaPharma: Research Funding; Novo Nordisk: Research Funding; CSL Behring: Research Funding; Bayer: Research Funding. Wijk: Axcella health: Research Funding; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding. Van Beers: Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; RR Mechatronics: Research Funding; Pfizer: Research Funding. Sheehan: Beam Therapeutics: Research Funding; Novartis: Research Funding; Forma Therapeutics: Research Funding.

EVALUATION OF THE LEUKOCYTE INDEX IN SICKLE CELL ANEMIA WITH THE USE OF HYDROXYUREA

The term sickle cell disease (SCD) is used to describe a group of genetic disorders in which there is a predominance of HbS, a variant hemoglobin originated from a single nucleotide polymorphism (SNP) responsible for the exchange of a glutamic acid by valine in position 6 of ß-globin chain. The most severe form of the disease is homozygous (HbSS). Thus, sickle cell disease patients may present different clinical manifestations and inflammatory processes. A pharmacotherapeutic used for the treatment is Hydroxyurea. The action of this drug includes increasing fetal hemoglobin levels and improving clinical severity and hematological parameters. This study aimed to investigate hematological stress in patients with sickle cell anemia treated (or not) with hydroxyurea, and classified regarding the risk of severity by the Calculator of severity of sickle cell disease. DNA samples from 200 patients with sickle cell anemia, in steady state of the disease, using and not using hydroxyurea, were submitted to molecular analysis to confirm HbSS. Then, chronic stress was characterized from the neutrophil-lymphocyte ratio (NLR) through the analysis of the blood count and clinical history. NLR is an important inflammatory marker, its calculation is indicated for patients with sickle cell disease and values above one may indicate hematological stress. Statistical analyzes were performed using IBM SPSS Statistics 20 software. Data normality was verified using the Shapiro-Wilk test. Assessed for non-normality, the non-parametric Wilcoxon test was performed to compare the means between the leukocyte profile and the use of hydroxyurea. Then, a comparison was made between the risk of death of patients who were (or not) treated with hydroxyurea. The results were shown as mean and standard deviation, with a significance level of 0.05. The means and standard deviation were NLR/With HU (1.76 ±1.53) and NLR/Without HU (1.65 ±1.07). In order to verify the difference between the means, we used the Wilcoxon test whose value was p = 0.975. Thus, we observed that there was no difference between leukocyte stress and the use of Hydroxyurea. When comparing the risk of death of patients which use the drug (1.96 ±0.73) and those who do not use it (2.22 ±0.75), we noticed that there were significant differences between the groups (p = 0.01). Therefore, the drug can contribute to reduce the risk of death. The non-relation between leukocyte stress and the use of hydroxyurea reported in this study is not well documented in the literature. However, we observed an increase in NLR in critically ill patients with sickle cell disease classified by the Calculator of severity of sickle cell disease. The role of hydroxyurea in the risk of life for patients with sickle cell anemia is well documented. It is known that it can help reducing the number of hospitalizations, length of stay, less occurrence of acute chest syndrome, lower morbidity and mortality rate, contributing to an increase of up to 40% in patient survival. Our results corroborate literature data. There was no relationship between stress through the NLR and the use of hydroxyurea, but there is a relationship between the severity of the disease and the use of the medication. Relating leukocyte stress with disease severity as well as the impact of hydroxyurea on these indices is important to understand the clinical manifestations of sickle cell anemia patients.

Evaluation of Vaso-occlusive Crisis Management With Patient-Controlled Analgesia in Children With Sickle Cell Disease Requiring Hospitalization.

The aim of this study was to review the use of patient-controlled analgesia (PCA) in sickle cell disease (SCD) for pediatric patients with vaso-occlusive crisis (VOC) in our institution and to compare the effect of early vs late PCA start on pain relief and LOS. This retrospective study included all pediatric patients treated with PCA for a severe VOC from 2010 to 2016. "Early-PCA" was defined as start of PCA within 48 hours of arrival. Time to reach adequate analgesia was defined as the time to reach 2 consecutive pain scores less than 5/10 at 4-hour interval. During the study period, 46 patients presented 87 episodes of VOC treated with PCA. Sixty-three patients with VOC were treated with Early-PCA and 24 with Late-PCA. Both groups were comparable except for median pain score at admission; the Early-PCA group had higher scores: 9.0/10 vs 7.0/10. Time to reach adequate analgesia could be evaluated only in a subset of patients (n = 32) but was shorter in the Early-PCA group with a median difference of 41.0 hours (95% CI -82.0 to -6.0). Early-PCA was associated with a median reduction in LOS of 3.4 days (95% CI -4.9 to -1.9). There was no difference between the 2 groups in terms of side effects and occurrence of acute chest syndrome during hospitalization. In this study, a reduced time to reach adequate analgesia and LOS was noted in the Early-PCA group for severe VOC. A prospective study is required to confirm these results.

Actions of L-Glutamine vs. COVID-19 Suggest Additional Benefit in Sickle Cell Disease

Background:The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection associated with coronavirus disease 2019 (COVID-19) causes a 3- to 9-fold higher age-adjusted mortality in African American and Hispanic populations, the major US racial groups affected by sickle cell disease (SCD). The Centers for Disease Control designates SCD as a condition at increased risk for severe COVID-19. An urgent need for repurposing of available and safe therapeutics has been cited for such high-risk populations until vaccines are widely available.L-glutamine (GLN) ameliorates clinical pathology of SCD related to elements of COVID-19. Multiple systemic complications of COVID-19 are increasingly attributed to oxidative damage, a target which GLN regulates. Prescription-grade L-glutamine (PGLG) (Endari®, Emmaus Medical) decreases oxidative stress by increasing the ratio of reduced nicotinamide adenine dinucleotide (NAD) to total NAD, which may increase availability of reduced glutathione. PGLG also decreases red cell endothelial adhesion in patients with SCD. Of note, additional analysis of the phase 3 trial demonstrated a 63% lower occurrence of acute chest syndrome (ACS) in PGLG-treated SCD patients compared to control, which has important relevance in the pandemic. A recent report of two computational screens of FDA-approved therapeutics, directed to protein and chemistry targets and to gene expression changes induced by SARS-CoV-2, predicts glutathione and GLN are highly likely to confer benefit in COVID-19 (Kim, J Translat Med, 2020).Methods:We therefore reviewed reports of multi-system effects of GLN in experimental respiratory distress animal models and in ICU and COVID-19 patients. We focused on contributors to cytokine storm and acute respiratory distress syndrome (ARDS), the leading causes of mortality in COVID-19 (Huang, Lancet, 2020). We also conducted a clinical trial in hospitalized COVID-19 patients on ESPEN-recommended nutrition +/- GLN.Results:In experimental ARDS, sepsis, and endotoxin-induced lung injury, GLN decreases consolidation, pulmonary edema, and neutrophil infiltration and increases lung compliance, oxygen saturation, heat shock protein activation, and survival by 2.5-fold over saline controls (Perng WC, Clin Exp Pharmacol Physiol, 2010; Singleton, Crit Care Med, 2005). Patients with severe COVID-19 have increased proinflammatory cytokines; interleukin 6 (IL-6) levels predict and contribute to severity of COVID-19 (Yuki, Clin Immunol, 2020). GLN modulates inflammatory responses by suppressing C-reactive protein, IL-6, and TNF-α release; it also reduces IL-6 in murine studies (37% decrease,p< 0.05; Chuang, BMC Pulm Med, 2014), which could benefit COVID-19 patients.Myocardial injury occurs in up to 12% of COVID-19 patients directly with viral entry through ACE-2 receptors, microvascular damage, endothelial shedding, and inflammation-mediated damage, which GLN protects against (Shi, Eur Heart J, 2020; Shi, JAMA Cardiol, 2020; Shao, Pak J Med Sci, 2015). Inflammatory states lead to GLN consumption and negative GLN balance (Santos, Amino Acids, 2019). Deficient plasma GLN (< 420 µmol/L) is a defined risk for higher mortality in ICU and COVID-19 patients (Shen, Cell, 2020). Glutathione deficiency contributes to SARS-CoV-2 oxidative lung damage and severe disease (Polonikov, ACS Infect Dis, 2020).In a recent clinical trial, patients were confirmed to have SARS-CoV-2 by RT-PCR, had positive CT scans, and were admitted from a COVID-19 clinic. Both arms received ESPEN-recommended nutrition for COVID-19 alone or with GLN (10 grams, 3 times/day; see Table).Conclusions:GLN and glutathione deficiency contribute to COVID-19 severity, and GLN has salutary biologic actions on reducing lung pathology, mediators of cytokine storm, and myocardial injury in animal models, SCD, and ICU patients. GLN reduces severity in standard risk COVID-19 patientsafterinfection has occurred. These findings, combined with computational prediction of GLN benefit vs. COVID-19, support the hypothesis that PGLG treatmentprior toSARS-CoV-2 infection mayreducethe development of severe COVID-19 in SCD and perhaps other high-risk populations. The data as a whole provides a strong rationale for a controlled clinical trial of PGLG toreducesevere COVID-19 in high-risk SCD patients and improve outcomes if infection occurs.DisclosuresCengiz:Biruni University Medical Faculty:Current Employment;Istanbul University-Cerrahpasa Medical Faculty:Ended employment in the past 24 months.Yavuzer:Istanbul University-Cerrahpasa, Cerrahpasa School of Medicine, Department of Internal Medicine, Division of Geriatrics:Current Employment.Yavuzer:Biruni University Medical Faculty:Current Employment;Istanbul University-Cerrahpasa Mediacl Faculty:Ended employment in the past 24 months.Tang:Kaiser Permanente:Current Employment.Ward:Emmaus Medical, Inc.:Current Employment.Goodrow:Emmaus Medical, Inc.:Current Employment;Emmaus Life Sciences Shareholder:Current equity holder in publicly-traded company.Ludlum:Emmaus Life Sciences, Inc.:Consultancy, Current equity holder in publicly-traded company.Stark:Emmaus Life Sciences Shareholder:Current equity holder in publicly-traded company;Emmaus Medical, Inc:Current Employment.Perrine:Cetya Inc.:Membership on an entity’s Board of Directors or advisory committees;Phoenicia Bioscience:Current Employment, Current equity holder in private company, Membership on an entity’s Board of Directors or advisory committees;Phoenicia Therapeutics:Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties;Boston University School of Medicine:Current Employment, Patents & Royalties;Viracta Therapeutics:Patents & Royalties.

Predictors of Maternal Morbidity Among Participants Enrolled in the Sickle Cell Disease Implementation Consortium Registry

Introduction Pregnancy in sickle cell disease (SCD) is associated with an exacerbation of SCD-related complications and an increased risk of maternal complications. The increased risk is partly due to physiologic adaptations in pregnancy, which include increased metabolic demands and a hypercoagulable state. The maternal death rate for SCD is 629 per 100,000 deliveries, compared to 12 per 100,000 deliveries in black women and 6 per 100,000 deliveries in the general population (Raider et al., 2016). Studies on maternal and perinatal outcomes of patients with SCD present inconsistent and conflicting results. Some studies have reported an increase in maternal complications such as pre-eclampsia, acute chest syndrome and thromboembolic events, while other studies have reported no significant risk in adverse maternal outcomes. The inconsistent findings reported in prior studies may be attributed to small sample sizes and single-centered sites. Our study aims to determine the prevalence and predictors of maternal morbidity among participants enrolled in the SCD Implementation Consortium (SCDIC) registry, which is the largest, most geographically diverse SCD participant sample in the United States. Methods This cross-sectional study included women enrolled in the SCDIC registry who had at least one pregnancy event. The SCDIC is composed of eight academic SCD centers across the United States and one data-coordinating center. Participants were enrolled in the SCDIC registry if they were 18 to 45 years of age and had a confirmed diagnosis of SCD. Enrolled participants completed a series of surveys that collected sociodemographic information, SCD and pregnancy history and data abstractions of participants' medical records was completed. Medical complications queried during pregnancy included: vaso-occlusive episodes, acute chest syndrome, blood transfusion requirement, preeclampsia, maternal diabetes and deep venous thrombosis. Descriptive analysis of sociodemographic, clinical and maternal characteristics was conducted. Bivariate analysis was performed using Chi-Square test, Mann-Whitney U test, t-test, and logistic regressions, as appropriate. A p-value of ≤ 0.05 was considered statistically significant for all analysis. Results The study sample included 743 women who had at least one pregnancy event, and a total of 1066 live births. Almost all women (96.3%) were African American, with a median age of 21 years (inter-quartile range of 19 to 23 years) at first birth. The majority had Hb SS SCD genotype (69.5%; 513 of the 738 with SCD genotype data). Of all reported pregnancies, participants did not use hydroxyurea during conception (78%), and pregnancy (84.5%). Only 2.7 % of the women reported using fertility drugs or assisted reproductive procedures. Seventy five percent of the pregnancies that ended in live births had maternal complications. The leading complications were vaso-occlusive episodes (61.2%), pregnancy requiring blood transfusion(s) (33.2%), preeclampsia (15.4%), deep venous thrombosis (5.6%) and acute chest syndrome (7.7%). When the pregnancies were stratified by SCD genotype, women with Hb SS had a higher occurrence of acute chest syndrome (63.4% vs. 26.7%), transfusion requirement (70.8% vs. 21%) and preeclampsia (66.7% vs 22.4%). In the univariate logistic regressions, multiparous women, with a history of adverse maternal outcomes in a previous pregnancy, had higher odds of vaso-occlusive episodes (OR: 3.42; 95% CI: 2.42-4.94) acute chest syndrome (OR:4.99; 95% CI:2.56- 9.48), transfusion requirement (OR:3.86; 95% CI:2.64- 5.69), and pre-eclampsia (OR:3.36; 95% CI:2.05-5.45). Conclusion In this large multicenter registry, we found pregnant women with SCD have significant maternal complications. Early antenatal care by healthcare providers knowledgeable about risk factors for adverse maternal outcomes in SCD is essential improve maternal and fetal outcomes and reduce the maternal death rate for SCD. Disclosures Hankins: Novartis: Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; MJH Life Sciences: Consultancy, Patents &amp; Royalties; UptoDate: Consultancy; National Heart, Lung, and Blood Institute: Honoraria, Research Funding; LINKS Incorporate Foundation: Research Funding; American Society of Pediatric Hematology/Oncology: Honoraria. Treadwell:Global Blood Therapeutics: Consultancy; UpToDate: Honoraria. King:Amphivena Therapeutics: Research Funding; Bioline: Consultancy; Celgene: Consultancy; Cell Works: Consultancy; Incyte: Consultancy; Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees; Novimmune: Research Funding; RiverVest: Consultancy; Tioma Therapuetics: Consultancy; WUGEN: Current equity holder in private company. Gordeuk:CSL Behring: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; Imara: Research Funding; Ironwood: Research Funding; Novartis: Consultancy. Kanter:SCDAA Medical and Research Advisory Board: Membership on an entity's Board of Directors or advisory committees; AGIOS: Membership on an entity's Board of Directors or advisory committees; BEAM: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; GLG: Honoraria; Jeffries: Honoraria; Cowen: Honoraria; Wells Fargo: Honoraria; NHLBI Sickle Cell Advisory Board: Membership on an entity's Board of Directors or advisory committees; Medscape: Honoraria; Guidepoint Global: Honoraria; bluebird bio, inc: Consultancy, Honoraria; Sanofi: Consultancy. Glassberg:Pfizer: Research Funding; Global Blood Therapeutics: Consultancy; Eli Lilly and Company: Research Funding. Shah:Novartis: Consultancy, Research Funding, Speakers Bureau; Alexion: Speakers Bureau; CSL Behring: Consultancy; Bluebird Bio: Consultancy; Global Blood Therapeutics: Consultancy, Research Funding, Speakers Bureau.

Oxygen Gradient Ektacytometry-Derived Biomarkers Are Associated with the Occurrence of Cerebral Infarction, Acute Chest Syndrome and Vaso-Occlusive Crisis in Sickle Cell Disease

Background: In sickle cell disease (SCD), hemoglobin S (HbS) polymerizes upon deoxygenation, reducing red blood cell (RBC) deformability. RBC deformability can be measured over a gradient of oxygen tensions (pO2) with the Laser Optical Rotational Red Cell Analyzer (Lorrca) ektacytometer (RR Mechatronics). Oxygen gradient ektacytometry generates 3 key parameters: 1) EImax, RBC deformability at normoxia; 2) EImin, minimum RBC deformability upon deoxygenation; and 3) the point of sickling (PoS): the oxygen tension at which a 5% decrease in deformability is observed during deoxygenation, reflecting the patient-specific pO2 at which sickling begins (Figure 1A). Previously we showed that oxygen gradient ektacytometry-derived biomarkers correlate with measures of SCD disease severity and hemolytic rate (Rab et al. Blood 2018), and is associated with vaso-occlusive crisis (VOC) frequency (Rab et al, Blood 2019). In this study, we confirm these observations in 2 independent cohorts and extend it to occurrence of acute chest syndrome (ACS), stroke including silent cerebral infarction (SCI), and transcranial Doppler (TCD) outcome. Methods: We analyzed 2 cohorts of SCD patients; an adult patient cohort of 53 SCD patients, enrolled at either University Medical Center Utrecht, The Netherlands (UMCU, n=25) or Hospital Lyon France (LIBM, n=28), and a pediatric patient cohort of 190 SCD patients enrolled at Texas Children's Hospital, USA (TCH). Subjects were HbSS or HbS/β-thalassemia, with a substantial number of subjects on hydroxyurea (HU) therapy (adult cohort 66% and pediatric cohort 86%), and not on chronic transfusion therapy. Correlations between oxygen gradient ektacytometry-derived biomarkers and the clinical complications of stroke or silent infarcts (SCI), ACS, VOC were assessed in both pediatric and adult patients. Patient groups generally did not significantly differ significantly by age, gender or HU treatment in the adult cohort except for age, which was lower in the ACS+ group (25.3years (y) compared to 32.0y) and also lower in the VOC+ group (27.1y compared to 35.8y). In the pediatric cohort, patient groups differed significantly in the ACS+ group compared to the ACS- group by age (ACS- group 8.37, ACS+ group 10.9y) and HU treatment (ACS- group 76%, ACS+ group 93%). Similarly, age was significantly higher in the Stroke+ group compared to the Stroke- group (14.0y compared to 9.3y), which was also found when studying VOC (VOC+ group 11.6y, VOC- group 8.2y). Results: In the pediatric cohort, PoS was significantly higher in patients with ACS (mean 40.3 compared to 34.9 mmHg, p=0.0001, Figure 1B). In the adult cohort, PoS was also higher in those with ACS although this did not reach significance (p=0.053, Figure 1C). In the pediatric cohort, PoS was higher in patients with stroke or SI (mean 43.0 mmHg compared to mean 37.3 mmHg, p&amp;lt;0.05), Figure 1D). This finding was replicated in the adult cohort (p&amp;lt;0.05, Figure 1E). EImin and EImax in both cohorts were significantly lower in patients who experienced stroke or SCI (all p&amp;lt;0.05). PoS was higher and EImin and EImax lower in subjects with elevated TCD measurements (all p&amp;lt;0.01, Figure 1F and G). In the adult and pediatric patient cohort, PoS was higher in patients with recent VOC (both p&amp;lt;0.05, Figure 1H and I). Differences in mean PoS between pediatric and adult patient cohorts could be due to differences in treatment, age, genetic background or technical differences between Lorrca devices. Lower significance levels found in the adult patient cohort could be due to smaller sample size. Conclusion: We show that oxygen gradient ektacytometry provides functional, clinically relevant next generation biomarkers that are associated with ACS, stroke and VOC. This study therefore further validates the clinical usefulness of these biomarkers, in particular in relation to cerebral vasculopathy. Since our results merely describe an association and not causality further validation is warranted to establish how well oxygen gradient ektacytometry can assess disease severity. However, its parameters could already provide the clinician with information about patient RBC characteristics and sickling propensity that could aid in clinical decision making. Our results provide a rationale for further development of these biomarkers in the evaluation of novel therapies as part of clinical care, or clinical trial endpoints. Disclosures Rab: RR Mechatronics: Research Funding. Bos:RR Mechatronics: Research Funding. Cnossen:Takeda: Research Funding; Shire: Research Funding; Baxter: Research Funding; Bayer: Research Funding; Sobi: Research Funding; CSL behring: Research Funding; Nordic Pharma: Research Funding; Novo Nordisk: Research Funding; Pfizer: Research Funding. Wijk:Agios Pharmaceuticals Inc.: Research Funding; RR mechatronics: Research Funding. Sheehan:Emmaus: Research Funding; Global Blood Therapeutics: Research Funding; Novartis: Research Funding. van Beers:Pfizer: Research Funding; RR mechatronics: Research Funding; Agios: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding.

Sickle cell/β-thalassemia: Comparison of Sβ0 and Sβ+ Brazilian patients followed at a single institution

Objectives: In sickle cell/β-thalassemia, mutations in the corresponding β-globin genes are responsible for complex pathological events resulting in diverse clinical complications. The objective of this study was to provide an overview of the clinical and laboratory characteristics of patients with the syndrome, and of the degree of severity of clinical manifestations resulting from the β-thalassemia mutation.Methods: A retrospective chart review was performed on 46 patients with sickle cell/β-thalassemia (31 Sβ° and 15 Sβ+), evaluating hematological parameters and end organ damage. Statistical analyzes were carried out in order to highlight differences between the two groups according to the nature of the thalassemia mutation.Results: As expected, patients with the Sβ0 phenotype had a higher degree of hematological involvement in comparison to Sβ+ patients; with lower hemoglobin levels, and signs of more intense chronic hemolysis. However, Sβ+ patients were more prone to the occurrence of acute chest syndrome. The impact of the thalassemia mutation upon total body and bone composition was also evident, as Sβ0 patients presented lower body mass index (BMI) and bone mineral density. The degree of bone damage correlated to lower BMI and hemoglobin levels, as well as plaquetosis, monocytosis and elevated lactate dehydrogenase, possibly reflecting the effects of hemolysis and inflammation upon bone metabolism and body constitution.Conclusions: This study identified significant differences among sickle cell/β-thalassemia patients according to the beta mutation involvement, pointing to an important predictor of disease severity.

Endothelial Nitric Oxide Synthase (-786T>C) and Endothelin-1 (5665G>T) Gene Polymorphisms as Vascular Dysfunction Risk Factors in Sickle Cell Anemia.

Sickle cell anemia (SCA) patients have vascular complications, and polymorphisms in endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) genes were associated with ET-1 and nitric oxide disturbance. We investigate the association of ET-1 5665G>T and eNOS −786T>C polymorphisms with soluble adhesion molecules (sVCAM-1 and sICAM-1), biochemical markers, and medical history. We studied 101 SCA patients; carriers of eNOS minor allele (C) had the highest levels of sVCAM-1, and carriers of ET-1 minor allele had more occurrence of acute chest syndrome (ACS). The multivariate analysis suggested the influence of the ET-1 gene on ACS outcome and an association of the eNOS gene with upper respiratory tract infection. We suggest that eNOS and ET-1 gene polymorphisms can influence SCA pathophysiology and that eNOS variant in SCA patients might be important to nitric oxide activity and vascular alteration. We found an association of the ET-1 minor allele in ACS, showing the importance of genetic screening in SCA.

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Introduction: In patients with sickle cell disease (SCD), sickle cell crisis (SCC) is a frequent cause of emergency department (ED) visit. Acute chest syndrome (ACS) is a known complication in patients with SCD and is a major cause of morbidity and mortality. Outcome data are limited to single center studies and there is a paucity of data regarding ED visits and resource utilization for patients with SCC and ACS. Methods: We performed a retrospective analysis of the Nationwide Emergency Department Sample (NEDS) for the years 2008 to 2010. The NEDS is a part of the Healthcare Cost and Utilization Project sponsored by the Agency for Healthcare Research and Quality. All children (aged <=21 years) visiting hospital based EDs with a diagnosis of sickle cell crisis (ICD-9-CM codes of 282.42, 282.62, 282.64, and 282.69) were selected. Occurrence of acute chest syndrome (ICD-9-CM code of 517.3) was estimated for these ED visits. Characteristics examined included age, gender, and type of sickle cell disease leading to crisis. Outcomes examined included disposition information following ED visit, hospital ED charges, and hospital mortality. Results: During the study period, there were a total of 149,472 ED visits for sickle cell crisis. The mean age of these patients was 14.6 years. Males comprised 49.3% of all ED visits. Close to 90.7% of all ED visits had Hb-SS disease with crisis, 3.3% had sickle-cell thalassemia with crisis, and 2.5% had sickle-cell/HB-C disease with crisis. About 3.6% had other sickle-cell disease with crisis. Close to 6.6% had acute chest syndrome. Medicaid was the major payer covering 62.2% of all ED visits. Twenty-six patients died in the ED while 116 died following admission as inpatients into the same hospital. Following ED visit, 42.3% were discharged routinely, 53.9% were admitted as inpatients into the same hospital, and 2.5% were transferred to another short-term hospital. The mean ED charge (inflation adjusted to year 2010) per visit was $2,162 and the total ED charges across the entire United States was $276.7 million. Conclusions: In this large retrospective nationwide emergency department study, sickle cell crisis was a frequent cause of emergency department visits in children with sickle cell disease. Acute chest syndrome is not an uncommon complication and is associated with significant utilization of hospital resources.

Hydroxyurea Is Associated With Lower Costs of Care of Young Children With Sickle Cell Anemia

In the BABY HUG trial, young children with sickle cell anemia randomized to receive hydroxyurea had fewer episodes of pain, hospitalization, and transfusions. With anticipated broader use of hydroxyurea in this population, we sought to estimate medical costs of care in treated versus untreated children. The BABY HUG database was used to compare inpatient events in subjects receiving hydroxyurea with those receiving placebo. Unit costs were estimated from the 2009 MarketScan Multi-state Medicaid Database for children with sickle cell disease, aged 1 to 3 years. Inpatient costs were based on length of hospital stay, modified by the occurrence of acute chest syndrome, splenic sequestration, or transfusion. Outpatient expenses were based on the schedule required for BABY HUG and a "standard" schedule for 1- to 3-year-olds with sickle cell anemia. There were 232 hospitalizations in the subjects receiving hydroxyurea and 324 in those on placebo; length of hospital stay was similar in the 2 groups. Estimated outpatient expenses were greater in those receiving hydroxyurea, but these were overshadowed by inpatient costs. The total estimated annual cost for those on hydroxyurea ($11 072) was 21% less than the cost of those on placebo ($13 962; P = .038). Savings on inpatient care resulted in a significantly lower overall estimated medical care cost for young children with sickle cell anemia who were receiving hydroxyurea compared with those receiving placebo. Because cost savings are likely to increase with age, these data provide additional support for broad use of hydroxyurea treatment in this population.

Soluble Vascular Cell Adhesion Molecule Levels, Endothelin-1 and Endothelial Nitric Oxide Synthase Gene Polymorphisms: Association with Clinical Symptoms in Sickle Cell Anemia.

AbstractAbstract 2118 Introduction:Vascular occlusions trigger most of the acute and chronic sickle cell anemia (HbSS) clinical complications and have been associated with high levels of soluble adhesion molecules and leukocytes activation. Accumulated evidence from clinical and experimental data shows that endothelin-1 (ET-1) plays an important role in the pathophysiology of the vascular system, because of its vasoconstrictor and hypertrophic activities. Endothelial nitric oxide synthase (eNOS) is an enzyme involved in nitric oxide (NO) synthesis pathway, a potent vasodilator and anti-inflammatory molecule. Polymorphisms in ET-1 and eNOS genes are associated with disturbance in ET-1 production and with reduced NO production respectively. The aim of this study was investigate the ET-1 5665G>T gene polymorphism and eNOS 786T>C gene promoter polymorphism with levels of soluble Intercellular Adhesion Molecule 1 (sICAM-1) and soluble Vascular Cell Adhesion Molecule 1 (sVCAM-1), biochemical markers and medical history of HbSS patients. Patients and Methods:We studied 51 HbSS patients from Northeast Brazil in attendance of the outpatient's clinic of the Foundation of Hematology and Hemotherapy of Bahia (HEMOBA). Biochemical analyses were measured by colorimetric methods, soluble adhesion molecules were measured by ELISA and the complete medical history was recorded by patient's record. The study was approved by the FIOCRUZ ethical committee and informed consents were signed by patients or official responsible.cerqueira Results:Our results showed genotype frequencies of 62.7% (32/51) of wild type (GG), 35.3% (18/51) of heterozygous (GT) and 2% (1/51) of homozygous (TT) for ET-1 5665G>T gene polymorphism. The eNOS 786T>C gene polymorphism showed 60.5% (23/38) of wild type, 34.2% (13/38) of heterozygous and 5.3% (2/38) homozygous. Both polymorphisms were in Hardy-Weinberg equilibrium. HbSS patients carriers of eNOS mutant allele (C) had the highest levels of sVCAM-1 (p= 0.015) (Fig. 1). Levels of sICAM were not related to any studied gene polymorphism. However, regarding to patients clinical history, we found a raised occurrence of acute chest syndrome (ACS) in carries of the ET-1 5665G>T mutant allele (Fig. 2). Discussion and Conclusion:Our study suggests that eNOS 786T>C and ET-1 5665G>T gene polymorphisms can participate of the HbSS pathophysiology. It is well known that high levels of circulating sVCAM are associating to an increased inflammatory state and VOC susceptibility, and our data show that eNOS variant in HbSS patients might be important to NO activity and anti-inflammatory vascular process. Also, the raised frequency of ACS, a major clinical feature in SCA which leads to patient mortality, was associated with the ET-1 variant showing the importance of the studied genes screening and their participation in these key molecules mechanism related to vascular health and VOC process. [Display omitted] [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Hemorheological risk factors of acute chest syndrome and painful vaso-occlusive crisis in children with sickle cell disease

Little is known about the effects of blood rheology on the occurrence of acute chest syndrome and painful vaso-occlusive crises in children with sickle cell anemia and hemoglobin SC disease. To address this issue, steady-state hemorheological profiles (blood viscosity, red blood cell deformability, aggregation properties) and hematologic parameters were assessed in 44 children with sickle cell anemia and 49 children with hemoglobin SC disease (8-16 years old) followed since birth. Clinical charts were retrospectively reviewed to determine prior acute chest syndrome or vaso-occlusive episodes, and rates of these complications were calculated. Multivariate analysis revealed that: 1) a higher steady-state blood viscosity was associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, but not in children with hemoglobin SC disease; 2) a higher steady-state red blood cell disaggregation threshold was associated with previous history of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. Our results indicate for the first time that the red blood cell aggregation properties may play a role in the pathophysiology of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. In addition, whereas greater blood viscosity is associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, no association was found in children with hemoglobin SC disease, underscoring differences in the etiology of vaso-occlusive crises between sickle cell anemia and hemoglobin SC disease.

Optimizing Hydroxyurea Use in Children with Sickle Cell Disease: Least Tolerated Dose Is Effective

Abstract 4851 Background:Hydroxyurea (HU) is an antimetabolite that effectively ameliorates the course of sickle cell disease (SCD). Starting dose is usually 20 mg/kg/day and the dose is escalated up to 35 mg/kg/day in most of the centers. In Oman, due to high level of consanguinity, ethnic neutropenia affects around 10% of population rendering higher doses difficult to maintain in most of the patients. Materials and Methods:161 patients (age 2–16 years, 61% male and 39% female) with SCD at Sultan Qaboos University Hospital, Muscat, Oman, were started on HU for clinically severe course (defined as: annual vaso occlusive crisis admissions more than 3, and/or occurrence of acute chest syndrome) with starting dose of 15 mg/kg and a mean dose of 18 mg/kg/day. All patients were included in the study except for 19 patients who were excluded for various reasons (8 lost follow up, 6 stopped HU by parents, and 5 stopped due to side effects: dizziness, abdominal pain, and myelosuppression). Remaining 142 patients were followed up for median treatment duration of 4 years (range, 1.5–10 years). Patients were assessed for clinical and laboratory response to HU. Results:There was significant reduction in the annual number of admissions due to vaso occlusive crisis (P <0.001, Wilcoxon Signed Ranks Test) with a mean of 4.7 and 1.5 before and after HU use respectively.There was also observed clinical improvement regarding the incidence of acute chest syndrome. Only 12 out of 39 patients initiated on HU for acute chest syndrome had a recurrent attack during a follow up period of 3–7 years.The laboratory parameters were consistent with previous reports: significant increase in hemoglobin level, fetal hemoglobin (HbF) level, Mean Corpuscular Volume, whereas significant decrease in platelet, absolute neutrophil, and absolute reticulocytic counts.All 142 patients tolerated the treatment well. Observed side effects included abdominal pain, dizziness, rash, tremor in one patient each. Of note, 21 patients (11.1%) developed neutropenia (ANC<1000 × 10^9/l) while 7 patients (3.7%) had thrombocytopenia (<100 × 10^9/l) which interrupted the treatment for period ranging from 3 weeks to 3 months only. Conclusion:In SCD patients with background of ethnic neutropenia, lower starting dose and limited range of dose escalation of HU ensured safety and yet did not affect efficacy. Disclosures:No relevant conflicts of interest to declare.

Risk Factors for Acute Chest Syndrome in Patients From Low Socioeconomic Background

A prospective cohort study to assess the risk factors for acute chest syndrome (ACS) in individuals with sickle cell disease was carried out in a referral center from Sergipe, Brazil. A total of 168 SS homozygotic individuals (ages between 12 wk and 26 y) were followed for 12 months. There were 134 admissions of 81 patients. There were 50 events of ACS, which was the second most frequent cause of hospital admission (after pain crisis). One patient died of ischemic stroke during follow up. In bivariate analysis, the following variables showed statistically significant associations with the occurrence of ACS: age less than 5 years, living in rural area, history of previous hospital admission; white blood cell count greater than 10,000/dL; hemoglobin concentration less than 7 g/dL and oxygen saturation ≤ 95% on admission. After controlling for confounding in multivariate logistic regression, only a history of previous admission remained as an independent predictor of ACS (relative risk=4.20; 95% confidence interval: 1.79-9.87; P=0.001). Patients with a positive history of hospital admission are under increased risk and should be monitored closely for prevention and early detection of ACS.

Comprehensive healthcare for individuals with sickle cell disease

Comprehensive healthcare for individuals with sickle cell disease