Clinical Manifestations Of Sickle Cell Disease Research Articles

Evolving Landscape of Sickle Cell Anemia Management in Africa: A Critical Review.

Sickle cell disease (SCD) is a prevalent inherited blood disorder, particularly affecting populations in Africa. This review examined the disease's burden, its diverse clinical presentations, and the challenges associated with its management in African settings. Africa bears a significant burden of SCD, with prevalence varying across countries and age groups. Newborn screening programs have highlighted the high prevalence of SCD at birth, emphasizing the need for early diagnosis and intervention. The clinical manifestations of SCD in Africa are multifaceted, encompassing acute complications like vaso-occlusive crises, acute chest syndrome, and stroke, as well as chronic complications such as organ damage and leg ulcers. Biological factors, including fetal hemoglobin levels, and demographic factors, like age and sex, influence disease severity and outcomes. The management of SCD in Africa faces numerous challenges. Limited access to resources, including diagnostic tools, medications, and trained healthcare professionals, hinders optimal care. The high cost of advanced therapies further restricts patient access. Cultural stigma and a lack of awareness create additional barriers to effective management. To address these challenges, early diagnosis through newborn screening programs and point-of-care testing is crucial. Comprehensive care models, including hydroxyurea therapy, pain management, and patient education, are essential for improving outcomes. Collaboration with international networks and leveraging local resources can enhance the sustainability of SCD programs. In conclusion, SCD significantly impacts African populations. Overcoming the challenges associated with its management requires addressing resource limitations, affordability issues, and cultural barriers. Early diagnosis, comprehensive care models, and ongoing research focused on affordability and accessibility are crucial for improving the lives of individuals living with SCD in Africa.

Hospitalization Events Among Adolescents and Adults With Sickle Cell Disease in a Tertiary Care Center in Central India.

Sickle cell disease (SCD) is an inherited red blood cell disorder, wherein mutation causes the substitution of glutamic acid to valine at the sixth position of the β-globin chain. These include sickle cell anemia (homozygous sickle mutation), sickle-beta thalassemia, and hemoglobin SCD. The clinical manifestations of SCD are protean. Individuals with SCD suffer from both acute and chronic complications, which include recurring episodes of pain commonly called vaso-occlusive crisis (VOC) - acute chest syndrome (ACS); aseptic necrosis of the bone; micro-infarction of the spleen, brain, and kidney; infections; stroke; and organ damage affecting every part of the body. SCD necessitates frequent hospitalizations because of severe complications, which pose a significant burden on caregivers and economic strain on healthcare systems. The pattern of hospital admission with SCD varies in different parts of the world. This study aimed to determine the causes of hospitalization among adolescent and adult patients with SCD and to determine factors associated with their hospital stay. The study was a hospital-based prospective observational study comprising adolescent and adult patients diagnosed with SCD, aged 15-45 years, who were hospitalized in the Department of General Medicine at All India Institute of Medical Sciences in Raipur from August 2021 to August 2022. According to our study, the primary reason for hospitalization was a painful crisis, accounting for 63% of cases, followed by infection (17%), ACS (11%), and acute hemolytic crisis (9%). Notably, we did not observe any significant differences between genders and causes of admission (p > 0.05). Joint pain (p = 0.005), back pain (p = 0.001), and chest pain (p = 0.001) were more frequently reported by adults over the age of 19. In addition, our analysis of the duration of hospital stays and various factors revealed that patients admitted for infections had a significantly longer mean hospital stay duration (p = 0.040). Acute painful crises were the primary cause of hospital admission among individuals with SCD; many patients also encountered infections and ACS. Furthermore, patients who experienced infections and VOC had a lengthier duration of hospital stay. Therefore, it is essential to provide them with comprehensive instructions on various preventive measures against infections and the factors that trigger painful crises.

Orthopaedic Diagnoses in the Black Pediatric Population.

The Black pediatric population is one that has been historically underserved and continues to have unmet needs. Factors including lack of diversity in orthopaedic studies and in historical standards, such as bone age, may inadvertently lead to inferior care. There are certain conditions in this population for which the practicing orthopaedic surgeon should have a higher degree of suspicion, including slipped capital femoral epiphysis, Blount disease, and postaxial polydactyly. Systemic diseases with higher rates in this population have orthopaedic manifestations, including sickle cell disease, vitamin D deficiency, and obesity. Racial discrepancies in access to prenatal care can have orthopaedic consequences for babies, especially cerebral palsy and myelodysplasia. Racial discrepancy exists in evaluation for nonaccidental trauma. Increased awareness of these issues better prepares practitioners to provide equitable care.

Impact of Abnormal Leukocyte Count in the Pathophysiology of Sickle Cell Anemia.

Sickle cell disease (SCD) is a hereditary disease that causes deoxygenated erythrocytes to stiffen, resulting in vaso-occlusive crises, endothelial damage, organ failure and systemic consequences. An abnormal leukocyte count is associated with a worse clinical picture in SCD. I studied the link between an abnormal leukocyte count and sickle cell disease. I used the PRISMA guidelines to conduct a systematic review of 5 different clinical literatures that discussed the link. Use of databases including Web of Science, Scopus, Cochrane Library, MEDLINE, ScienceDirect, EMBASE, and JSTOR to make our findings. SCD is a red cell disorder, but an elevated leukocyte count plays a significant role in its pathophysiology. Sickled red cells adhere better to leukocytes when compared to normal red cells, which explains the worse clinical picture seen in sickle cell patients. Hydroxyurea therapy inhibits the recruitment and invasion of neutrophils, which lowers vaso-occlusion. An elevated leukocyte count is responsible for worse clinical manifestations in SCD, eg, clinical stroke, acute chest syndrome, end organ damage, and infarction pain. Leukocytes attach to erythrocytes and vascular endothelium to cause vaso-occlusion, responsible for these effects. They also elaborate inflammatory mediators to aid the process. The higher the leukocyte count, the worse the effects. Hydroxyurea is very helpful in disrupting several pathways of leukocyte contribution to SCD pathophysiology. Therefore, more research on other pharmacologic agents that interfere with this disease process is necessary. Lastly, there is a need for further research into the effects of a reduced leukocyte count in SCD pathophysiology.

P101: GUT MICROBIOTA IMPACT ON ANGOLAN CHILDREN WITH SICKLE CELL DISEASE

Background: Sickle cell disease (SCD) is one of the most prevalent genetic diseases, affecting between 20 and 25 million people worldwide. In the Sub-Saharan Africa, where it is more prevalent, it contributes to 50–80% of under-5 mortality. Clinical manifestations of SCD are very heterogeneous and the intestinal microbiome appears to be crucial in the modulation of inflammation, cell adhesion and induction of aged neutrophils, which are the main interveners of recurrent vaso-occlusive crisis. Enterocyte injury, increased permeability, altered microbial composition, and bacterial overgrowth have all been documented as microbial and pathophysiologic changes in the gut microbiome of SCD patients in recent research studies. Microbiota analysis in SCD populations will be essential to demonstrate the importance of specific bacteria and their function in this disease and provide new insights for attenuating symptoms and new drug targets. Aims: Given this, our aim is to sequence by NGS bacterial 16S RNA gene in order to characterize the gut microbiome of SCD children and healthy siblings, as a control. A written informed consent was presented and explained to all the guardian participants prior to the data collection. A total of 72 stool samples were obtained from children between 3–14 years old. Results: Our preliminary results showed that the SCD and control samples exhibit some notable differences in microbiota relative abundance, at different levels of classification. Children with the disease have a higher number of the phylum Actinobacteria (p=0.013) with a mean of sequences of 5.47% (± 3.49), while the siblings have a mean of 3.25% (± 2.98). As for the genus level, only Clostridium cluster XI bacteria was more prevalent in the SCD children, whereas the siblings had higher numbers of Blautia, Aestuariispira, Campylobacter, Helicobacter, Polaribacter and Anaerorhabdus. Conclusion: There is still much to learn before fully relying on the therapeutic approaches for gut modulation, which is why more research in this field is crucial to making this a reality. This works as been supported by FCT/Aga Khan (project n°330842553) and FCT/MCTES (UIDB/05608/2020 and UIDP/05608/2020) –H&TRC.

A call to start hydroxyurea by 6months of age and before the advent of sickle cell disease complications.

A call to start hydroxyurea by 6months of age and before the advent of sickle cell disease complications.

Alemtuzumab/Low Dose TBI Conditioning Facilitates Stable Long-Term Donor Hematopoietic Cell Engraftment from Sibling Donors in Children with Sickle Cell Disease

BackgroundHematopoietic stem cell transplant (HCT) is the only established curative approach for sickle cell disease (SCD). Due to the high toxicity profile of myeloablative regimens, some adult patients with severe sickle cell anemia are not eligible for such therapy. However, a new adult nonmyeloablative protocol (National Institutes of Health, NIH protocol) described by Hsieh et al. (2014) was able to achieve a curative degree of mixed donor chimerisms with minimal transplant-related complications. The NIH protocol includes alemtuzumab, low dose total-body irradiation (TBI) of 300 cGy, and prolonged sirolimus for graft-versus-host disease (GVHD) prophylaxis for those recipients with a matched-sibling donor (MSD).The Alberta Children's Hospital has adopted this published regimen for MSD HCT in adolescents and younger children with SCD since the NIH data was presented in 2013.To our knowledge, there is no published literature describing the application of the NIH protocol in a pediatric population; the youngest subject in the referenced adult study was 16 years of age.MethodsThis retrospective cohort describes outcomes of nonmyeloablative allogeneic MSD HCT in children and adolescents with SCD who underwent HCT between 2013-2017. Fourteen patients with SCD under 18 years of age at the time of HCT received the NIH conditioning regimen. HLA-matched siblings had either normal hemoglobin or sickle cell trait and of the appropriate weight/height to donate peripheral blood stem cells (PBSCs) without blood priming of the apheresis circuit.The conditioning regimen consisted of alemtuzumab 1.0 mg/kg administered subcutaneously daily divided over five days (Days -7 to Day -3). Patients received a single TBI dose of 300 cGy on day -2, with testicular shielding for male recipients. GVHD prophylaxis consisted of a sirolimus loading dose of 3mg/m2/dose (PO) on day -1, followed by 1mg/m2/dose once daily starting on Day 0. PBSCs were typically collected on Day -3 to allow for cancellation of the HCT before TBI in the event of failed mobilization. Unmanipulated PBSCs were infused fresh on Day 0. Patients were eligible for early discharge post-transplant even prior to neutrophil engraftment. Weaning of sirolimus was initiated no earlier than 1-year post-HCT and if donor T-cell chimerisms were greater than 50%. Treatment failure was defined as clinical manifestation of SCD, failure to start weaning sirolimus by 2-years post-HSCT, or a failure to complete a sirolimus wean by 2.5 years post-HCT.ResultsFourteen patients (3 M,11 F) are included on this retrospective study. Median age at HCT was 11 years. Post-HCT follow-up ranges from 1 to 48 months (median 17). There were no failed donor stem cell mobilizations. Patients received a median of 11.4x106 CD34 cells per kilogram of body weight.All patients were discharged home prior to neutrophil engraftment with a median hospital stay of 7 days (range 5-19). All patients had donor neutrophil engraftment at a median of 21 days (mean= 22, SD= 4) and platelet engraftment at median of 14 days (mean= 12, SD= 14). Six patients never required platelet transfusion. Readmission after initial discharge was required in 9/14 patients with an average of 1 readmission/patient (range 1-4), typically for fever or CMV pre-emptive therapy. One patient developed septic shock with Acinetobacter ursingii related to poor central line care at home.All patients are currently alive. Post-HCT, there have been no cases of graft failure, sickling crises, veno-occlusive disease, idiopathic pneumonia syndrome, cerebral hemorrhage, PRES, or PTLD. Although 6/14 patients had CMV reactivation, only 3 patients required pre-emptive therapy. None had CMV/EBV disease.There were no treatment failures as defined by protocol. Currently, 8 patients are off sirolimus, 1 is currently weaning, with no secondary graft failure events. Only 2 patients over 1-year post-HCT have not initiated sirolimus weaning. There have been no cases of acute or chronic graft-versus-host disease.ConclusionsNonmyeloablative conditioning regimen is safe and effective as curative therapy for children with SCD. Outpatient management pre-engraftment was feasible in this population. In contrast to adult data, sirolimus weaning was possible in most patients by one-year post-HCT. Graft integrity was maintained after discontinuation of sirolimus in all eligible patients. [Display omitted] DisclosuresGuilcher:Patient Access Solutions: Consultancy; Canada Market Research: Consultancy; Jazz pharmaceuticals: Consultancy. Bruce:Bristol-Meyers-Squibb - consultant 2016-2017: Consultancy; ovartis consult and ad board 2015-2016: Consultancy; Apopharma 2015: Consultancy.

Scalp Swelling and Headache in a 12-year-old Boy

1. Kathryn Westphal, MD* 2. Respicius Bakalemwa, MD† 3. Elizabeth Groothuis, MD, MPH* 1. *Department of Pediatrics, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL 2. †Department of Pediatrics, Bugando Medical Centre, Mwanza, Tanzania A 12-year-old boy with sickle cell disease (SCD) is admitted to a hospital in Mwanza, Tanzania, with acute onset of periorbital and scalp swelling. Associated symptoms include fever, headache, difficulty breathing, and back pain. Because resources in sub-Saharan Africa are limited, access to comprehensive care for patients with SCD is variable. The general principles of management focus on early diagnosis, parental education, prevention of infection with vaccinations and prophylactic medications, prompt treatment of infection and pain, the use of hydroxyurea for stroke prevention, and blood transfusions for life-threatening anemia. This patient has a known diagnosis of SCD but has infrequent pain episodes and no previous transfusions. He is not receiving hydroxyurea or prophylaxis against bacterial infections or malaria. He has no history of stroke and no known head trauma. On presentation he is afebrile and his heart rate is 120 beats/min, respiratory rate is 40 breaths/min, and blood pressure is 105/75 mm Hg. His oxygen saturation is 92% in room air. Physical examination is significant for pallor, periorbital edema, scalp edema, dyspnea without adventitious lung sounds, and splenomegaly with diffuse abdominal tenderness. His scalp edema is fluctuant and extends posteriorly from the periorbital region, encompassing the entire scalp. Swelling is most prominent in the frontal and parietal areas. The overlying skin is nonerythematous and nontender but is warm to the touch. His neurologic examination has no focal findings, although generally he appears tired. Initial laboratory results demonstrate a white blood cell count of 84,000/μL (84×109/L) with a lymphocytic predominance (57%), a hemoglobin level of …

Osteonecrosis of mandible secondary to sickle cell crisis

<h3>Background</h3> Sickle cell disease (SCD) is an autosomal recessive hemoglobinopathy causing amino acid substitution in the B-hemoglobin chain of erythrocytes. SCD affects 1 in 500 African American children. SCD is associated with multiorgan morbidity and significant reduction in life expectancy. Vaso-occlusive crisis associated with SCD is characterized by acute pain and local tissue hypoxia and necrosis. The extremities, back, and chest are frequently affected, and jaw involvement is very rare. To the best of our knowledge, only 3 cases of jaw osteonecrosis secondary to SCD have been reported in the English-language literature. <h3>Case Summary</h3> A 38-year-old African American man with a history of SCD and avascular necrosis of the hips presented to an emergency department with severe pain in his back, legs, and chest due to a vaso-occlusive episode precipitated by physical overexertion. A few days later, the patient complained of left jaw pain and paresthesia. Computed tomography (CT) of the head with intravenous (IV) contrast, maxillofacial CT with IV contrast, and the remainder of the neurologic examinations were unremarkable. The oral medicine service was consulted, and physical examination of the patient demonstrated lingual gingival tissue swelling of the lower left molars. The mass was nonfluctuant with ulceration causing malalignment of tooth number 18. Bone biopsy revealed squamous mucosa with hemorrhagic foci, ulceration, and ectatic blood vessels with fragments of necrotic bone consistent with osteonecrosis. At the patient's 2-week follow-up visit, a small area of exposed necrotic bone was noted in the affected area. Maxillofacial CT without IV contrast showed mixed radiolucency and sclerosis with dehiscence along the lingual cortex of the posterior mandibular body and along the cortex of the retromolar trigone. Chlorhexidine gluconate 0.12% oral solution was prescribed, and debridement of the left posterior mandible and extraction of the lower left molars with local flap reconstruction were recommended by an oral and maxillofacial surgeon. The patient did not return for follow-up management. <h3>Conclusions</h3> Acute pain and chronic vasculopathy are significant complications of SCD. Jaw involvement in SCD is very rare, as illustrated in this case. It is important for oral health care professionals to understand the pathophysiology and clinical manifestations of SCD.

Early Results from a Phase 1/2 Study of Aru-1801 Gene Therapy for Sickle Cell Disease (SCD): Manufacturing Process Enhancements Improve Efficacy of a Modified Gamma Globin Lentivirus Vector and Reduced Intensity Conditioning Transplant

Introduction: ARU-1801 is a gene therapy consisting of autologous CD34+ hematopoietic stem cells and progenitors (HSCPs) transduced with a lentiviral vector (LV) encoding a modified γ-globinG16D gene. Preclinical studies in SCD mice have shown that g-globinG16D binds α-globin with higher affinity; hence, the g-globinG16D LV produces 1.5-2x more HbF/vector copy number (VCN) than a g-globin LV. Preliminary studies also show greater reduction in reticulocytes in SCD mice expressing HbFG16D compared to those expressing the same level of HbF, suggesting that HbFG16D may have a more potent anti-sickling effect than HbF. We hypothesized a high potency anti-sickling globin would allow ARU-1801 to be effective with reduced intensity conditioning (RIC). RIC would result in lower toxicities and resource utilization compared to myeloablative approaches, allowing access of gene therapy to a broader group of SCD patients. We previously reported early data from patient 1 (P1) and 2 (P2) in the ongoing Phase 1/2 study (NCT02186418), who were treated with drug product (DP) from the initial ARU-1801 manufacturing process (Process I). We now present the long-term data on these patients and early data from P3, the first patient treated with our new manufacturing process (Process II). Methods: Adults with severe SCD, as defined by recurrent vaso-occlusive events (VOE) and acute chest syndrome deemed eligible were enrolled. Manufacturing process improvements in Process II included optimized timing of HSCP collection after plerixafor mobilization, LV production and improved HSCP transduction. Prior to DP infusion, all patients received a single dose of IV melphalan (140 mg/m2 BSA) and were weaned off transfusions 3-6 months after DP infusion. Patients were monitored for safety, engraftment, VCN, anti-sickling Hb (ASG) expression, and hematological and clinical manifestations of SCD. Levels of ASG (including HbFG16D) are presented as fractions of endogenous Hb. Results: As of 28 July 2020, data from 3 patients treated with ARU-1801 are available. P1 (34yr old) has HbSβ0- and P2 (24yr old) has HbSβ+ thalassemia (2-3% HbA). Both have 30 months (mo) post-transplant (PT) follow up. P3 (19yr old) has HbSS genotype with 6 mo PT follow up. ARU-1801 demonstrated a favorable safety profile with no treatment-related adverse events to date. Time to neutrophil engraftment (ANC ≥500) was 9, 7, and 7 days PT, and time to platelet recovery (Plt &amp;gt;50,000) was 12, 7, and 6 days PT, in P1, P2, and P3, respectively. Figure 1 shows HSPC dose, conditioning exposure and gene transfer; Figure 2 shows ASG over time. Using Process I, P1 has shown stable expression of 20% HbFG16D, 31% ASG and 31%à64% F-cells over 2.5 years, despite a low DP VCN of 0.2 and low HSPC dose of 1.4 x106 cell/kg. P2 received a higher cell dose of 7.1 x106 cell/kg with a DP VCN of 0.47 but had below target melphalan exposure, likely due to rapid clearance from hyperfiltration (GFR= 200 mL/min/1.73m2). Despite lower engraftment and HbFG16D level, P2 maintains stable total ASG of 22% at 30 mo due to a compensatory increase in HbF. Using Process II, P3 received DP of 6.8 x106 cells/kg with a VCN of 1.0, and demonstrated an engrafted VCN of 0.74, 71% F-cells and 91% F-reticulocytes at 6 mo. As P3 is being weaned off transfusions, HbFG16D is progressively rising, showing the selective advantage to HbFG16D-containing RBCs. P1 and P2 have maintained improvements in VOEs, no VOE in P3 so far (data will be presented). Conclusion: We show that engraftment of ARU-1801 and amelioration of disease is possible with RIC using IV melphalan, with persistent stable ASG expression and meaningful improvement in VOEs in P1 and P2. P1 shows stable HbFG16D and high ASG despite low, albeit stable VCN. P2 had lower HSCP engraftment, which we hypothesize was due to below target melphalan exposure. Nevertheless, significant clinical benefit was observed in P2 due to stable ASG of 22% at mo 30. It is likely that the presence of this amount of HbFG16D has provided enough ASG to prevent sickling/ineffective erythropoiesis, resulting in the preferential survival of HbF+HbFG16D-expressing RBC. Process II DP in P3 resulted in 2-4X higher engraftment of transduced HSCPs at 6 mo. Additional process enhancements are under development for future treated patients. ARU-1801, administered with RIC, holds significant promise for achieving durable responses with a favorable safety profile in patients with severe SCD. Disclosures Asnani: Aruvant Sciences: Research Funding; Avicanna Ltd.: Research Funding. Lutzko:Aruvant Sciences: Patents &amp; Royalties: pre-clinical vector development. Lo:Aruvant Sciences: Current Employment. Little:Aruvant Sciences: Current Employment. McIntosh:Aruvant: Current Employment, Current equity holder in private company. Malik:Aruvant Sciences, Forma Therapeutics, Inc.: Consultancy; Aruvant Sciences, CSL Behring: Patents &amp; Royalties. OffLabel Disclosure: Plerixafor - stem cell mobiliziation Melphalan - chemotherapy conditioning pre autologous transplant with ARU-1801

Robust Pre-Clinical Results and Large-Scale Manufacturing Process for Edit-301: An Autologous Cell Therapy for the Potential Treatment of SCD

Sickle cell disease (SCD) is an inherited blood disorder affecting approximately 100,000 individuals in the United States. As fetal hemoglobin (HbF) has been shown to be protective against clinical manifestation of SCD, we are developing EDIT-301, an autologous cell therapy comprising CD34+ cells genetically modified using a Cas12a ribonucleoprotein (RNP) to promote HbF expression to treat SCD. Fetal hemoglobin induction for EDIT-301 is achieved by disrupting the HBG1 and HBG2 promoter distal CCAAT-box region where naturally occurring mutations are found to be associated with elevated HbF expression. Cas12a was selected over Cas9 due to the more productive and sustainable (NHEJ derived) indel profile, as well as high specificity. Using Cas12a RNP, on-target editing of ~90% was achieved in mobilized peripheral blood CD34+ cells (mPB-CD34+ cells) from both healthy and SCD donors at research scale with no detectable off targets. Editing of CD34+ cells led to an average of 43% and 54% of HbF expression in the erythroid progeny of normal donor and SCD donor cells respectively in a pancellular fashion (~93% population). The robust HbF induction in SCD red blood cells (RBCs) resulted in significant phenotypic and functional improvement including reduced sickling and increased deformability under hypoxia ex vivo. Using a microfluidic assay that replicated blood flow in microvasculature under varying oxygen conditions, SCD RBCs derived from RNP electroporated CD34+ cells showed improved rheological behavior. The rheology improvement under hypoxia was strongly correlated with the increased levels of HbF in each sample. Infusion of the modified CD34+ cells from normal donors into NBSGW mice resulted in long-term multi lineage and polyclonal reconstitution. Editing levels at 16 weeks post infusion were &amp;gt; 90% in all human lineages tested, demonstrating the efficient editing of SCID-repopulating hematopoietic stem cells (HSCs). Consistent with the high editing levels, human erythroid cells from the bone marrow of mice that received Cas12a-RNP treated cells demonstrated pancellular (~90% F+ RBCs) HbF expression averaging 40-50% of total hemoglobin compared to ~5% HbF observed in the control group. We have developed a consistent large-scale process using functionally closed, semi-automated systems suitable for use in clinical manufacturing. We have shown robust editing of normal donor CD34+ cells and SCID-repopulating HSCs with the clinical scale process. Editing levels of &amp;gt;90% were detected after long term engraftment in mice. In summary, we have demonstrated successful on-target editing of mPB CD34+ cells derived from both normal and SCD donors using a Cas12a RNP, which coincided with robust HbF induction and a phenotypic reduction of sickling in the SCD erythroid progeny, as well as improved rheological behavior. Editing of the HBG1 and HBG2 promoters using this RNP was highly specific with no measurable off-target. In vivo, cells from normal donors readily engrafted and reconstituted all blood cell lineages at levels comparable to unedited cells. Finally, a robust large-scale manufacturing process has been developed to supply material for the clinical setting. Based on these results, we are completing the activities required to assess EDIT-301 in the clinic as treatment for SCD. Disclosures De Dreuzy: Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company. Heath:Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company. Sousa:Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company. Janoudi:Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company. An:Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company. Albright:Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company. Teixeira:Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company. Monesmith:Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company. Zhang:Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company. Chang:Editas Medicine Inc.: Current Employment, Current equity holder in publicly-traded company.

Prevalence and Predictive Factors for Leg Ulcers in Sickle Cell Disease Patients in Saudi Arabia: A Cross-Sectional Observational Study.

IntroductionSaudi Arabia has a high prevalence of sickle cell disease (SCD). Leg ulceration is one of the complications associated with SCD. There is a gap in the literature in regard to the prevalence of leg ulcers among SCD patients in Saudi Arabia.ObjectivesThe primary objective of this study was to evaluate the lifetime prevalence of leg ulcers in SCD patients in our population and to study the predictive factors of leg ulcers by using sociodemographic factors, clinical manifestations of SCD, and other relevant factors like hydroxyurea.MethodsA cross-sectional study design was utilized. Data collection was done using an electronic survey to collect self-reported information for the prevalence of leg ulcers and possible associated factors. The survey was distributed using social media platforms. Chi-square test was used to test for the presence of an association between having leg ulcers and sociodemographic variables as well as SCD related history. Furthermore, binary logistic regression was utilized to determine factors predicting the incidence of leg ulcers among SCD.ResultsA total of 790 valid responses were included in the study. Among these, 646 were included in the analysis of leg ulcers prevalence. From them, 52 (8%) SCD patients reported a history of leg ulcers. The male to female ratio was (9.7% vs 7.2%). The age group most affected by leg ulcers was those older than 50 (16.7%). There was no significant association between a history of leg ulcers and sociodemographic variables. The only predictive factors for leg ulcers were having six to eight vaso-occlusive crises per month and having more than eight vaso-occlusive crises per month.ConclusionLeg ulcers among SCD patients in Saudi Arabia were considerably prevalent (8%). There was no statistically significant correlation between leg ulceration and sociodemographic variables. Leg ulcers were more likely in patients with a history of highly frequent vaso-occlusive crises. No association was found between the incidence of leg ulcers and other complications of sickle cell disease or hydroxyurea.

Clinical and epidemiological profile of sickle cell anemia in children: an integrative review

Objective: The aim of this study is to analyze the clinical epidemiological profile of children with sickle cell anemia published in the literature over the last ten years. Methods: It is an integrative review. To search the articles, the Virtual Health Library (VHL) was used, and the articles from the database of the Scientific and Technical Literature of Latin America and the Caribbean (LILACS) of the Medical Literature Analysis and Retrieval System Online (MEDLINE) database were selected, data from the Scientific Electronic Library Online (Scielo), with national and international publications, carried out from 2007 to 2017 through the following descriptors: Sickle Cell Anemia, Profile, Children. Results: The results revealed that brown-skinned 2 to 8 year old children with the SS type genotype were the most frequently mentioned with sickle cell anemia (SCA). Among the clinical manifestations of SCA, they indicated: the infection; acute splenic sequestration; behavioral and performance problems of social competence, pain, skin paleness, fever, weight and iron deficiency, short stature and problems prosthetics. Final considerations: It is concluded that early diagnosis and specific interventions will allow, in addition to reducing physical damage, the adoption of more proactive strategies in view of the limitations imposed by the disease.

Associations between endothelial dysfunction and clinical and laboratory parameters in children and adolescents with sickle cell anemia.

BackgroundHematological changes can drive damage of endothelial cells, which potentially lead to an early endothelial dysfunction in patients with sickle cell anemia (SCA). An association may exist between endothelial dysfunction and several clinical manifestations of SCA. The present study aims to evaluate the links between changes in endothelial function and clinical and laboratory parameters in children and adolescents with SCA.MethodsThis study included 40 children and adolescents with stable SCA as well as 25 healthy children; aged 6–18 years. All study subjects were evaluated for endothelial function using Doppler ultrasonography. In addition, a number of laboratory assays were performed, including reticulocyte and leukocyte counts as well as measurement of circulating levels of total bilirubin, C-reactive protein (CRP), glucose, lipoproteins and peripheral oxyhemoglobin saturation. These parameters were also compared between SCA patients who were undertaking hydroxyurea (HU) and those who were not.ResultsFlow-mediated vasodilation (FMD) values were found to be reduced in SCA patients compared with those detected in healthy controls. SCA individuals with lower FMD values exhibited higher number of hospital admissions due to vaso-occlusive events. Additional analyses revealed that patients who had decreased FMD values exhibited higher odds of acute chest syndrome (ACS) episodes. A preliminary analysis with limited number of individuals failed to demonstrate significant differences in FMD values between SCA individuals who were treated with HU and those who were not.ConclusionsChildren and adolescents with SCA exhibit impaired endothelial function. Reductions in FMD values are associated with ACS. These findings underline the potential use of FMD as screening strategy of SCA patients with severe prognosis at early stages.

High Foetal Haemoglobin in Sickle Cell Disease: Not so Protective?

High Foetal Haemoglobin in Sickle Cell Disease: Not so Protective?

Sickle‐cell disease in California: A population‐based description of emergency department utilization

Acute and chronic clinical manifestations of sickle-cell disease (SCD) lead to significant healthcare utilization, especially of the emergency department (ED). Limited population-level data are available in SCD with the ability to connect patients to visits, leaving us with minimal description of utilization patterns. Using ED discharge data with links between patients and visits, we sought to describe the California SCD population and its ED utilization patterns across facilities. Non-public California Office of Statewide Health Planning and Development data employ unique patient identifiers, linking patients, and visits. SCD patients of all ages are heavily reliant on Medicaid (46%). The majority of SCD Californians visit an ED more than once during a year (69%), but only a minority use more than one facility during a year (34%). However, adults with SCD have multiple visits and utilize multiple EDs in higher proportions than do children (72% vs. 60% and 40% vs. 21%, respectively). A higher proportion of visits to the ED are made by SCD adults, but a higher proportion of visits by children result in hospital admission. Uninsured adults outnumber uninsured children (16% vs. 5%). ED utilization by the California SCD population is described on a population level. Utilization patterns by adults point towards increased utilization in the population no longer eligible for Title V pediatric coverage for their disease. Further investigation using population-level socioeconomic and geographic correlates is warranted to evaluate the factors leading to ED utilization in SCD.

Contributions of Immune Cells to Vascular Occlusion in Sickle Cell Disease.

Sickle cell disease (SCD) results from a single missense mutation in the β-globin gene, making the gene product susceptible to polymerize in conditions of low O2 tension. The resulting polymers can disrupt the normal architecture of sickle red blood cells (sRBC), altering their membrane and promoting adherence. sRBC adhesion events within the vasculature produces the painful vaso-occlusive episodes that account for most of the morbidity and mortality of this disease.1 The mechanisms mediating vaso-occlusion (VOC) in SCD are not well understood. Several studies have shown that sRBC, most notably the immature reticulocytes, can bind to endothelial cells (EC) though multiple overlapping adhesion mechanisms. However, whether these interactions are directly involved in VOC is controversial. sRBC can clearly interact with other blood cells inside the vasculature. For example, in a humanized mouse model of SCD, sRBCs interact prominently with leukocytes that are adherent in inflamed venules.2 A role for leukocytes in VOC is consistent with clinical data that have linked leukocyte counts, but not reticulocyte counts, with clinical manifestations of SCD. High-speed multichannel fluorescence intravital microscopy (MFIM) using low doses of lineage-specific antibodies has shown that sRBCs interact specifically with adherent neutrophils.3 Most adherent neutrophils are not immobile but rather crawl along inflamed venules, and virtually all of them exhibit a polarized appearance in vivo with clustered L-selectin at the uropod. Inhibition of or deficiency in the endothelial selectins (E- and P-selectins) protects SCD mice from VOC. Recent studies into the individual role of each selectin have revealed, unexpectedly, a major function for E-selectin. Whereas E-selectin inhibition or deficiency does not significantly affect neutrophil adhesion in inflamed venules, it dramatically blocks the interactions of RBC with adherent neutrophils, suggesting that E-selectin signaling into an adherent leukocyte may induce RBC capture. We have found that RBCs carrying normal hemoglobin (nRBCs) also interact with adherent neutrophils in inflamed venules of wildtype mice. In the mouse, three glycoproteins, P-selectin glycoprotein ligand-1 (PSGL-1, encoded by the Selplg gene), CD44 (encoded by Cd44), and E-selectin ligand-1 (ESL-1, encoded by Glg1) mediate all E-selectin binding activity of leukocytes.4 Detailed analyses of Selplg−/− mice, Cd44−/− mice, or chimeric mice, in which Glg1 is knocked-down by RNA interference, revealed that E-selectin-induced signals are mediated specifically by Glg1. Using MFIM analyses, we have mapped the location of RBC captures on the leading edge of polarized neutrophils. Further investigations have revealed that RBC capture was mediated by the β2 integrin Mac-1 (αMβ2). We have developed a new method to assay Mac-1 activation on adherent leukocytes in live mice. These analyses have shown that Glg1-mediated signals activate αMβ2 regionally at the leading edge, allowing RBC capture. These results suggest a new pathway for the development of targeted therapies for VOC. The fact that genetically normal RBCs are captured by neutrophils through mechanisms similar to sRBCs also suggests broad functions for this paradigm in other thrombo-inflammatory diseases.

Nitric Oxide Effects in Sickle Cell Disease.

Sickle cell disease (SCD) is a complex hemoglobinopathy characterized by microvascular occlusion and hemolytic anemia. Patients suffer from a myriad of both acute and chronic problems affecting virtually every organ system. Historically, microvascular occlusion has been the focus of scientific investigations into these manifestations and the chronic hemolysis of SCD was overlooked. More recently, however, the importance of the pathophysiology of hemolysis has been appreciated and related to a subset of the clinical manifestations of SCD, including pulmonary hypertension, priapism, skin ulcers, and possibly stroke. This subphenotype of SCD has been convincingly related to impaired nitric oxide (NO) homeostasis due to hemolysis. NO has pleiotropic effects including vaso-dilatory, antioxidative, anti-adhesion, and anti-thrombotic properties, which are all potentially important in the pathophysiology of SCD. Perturbation of NO homeostasis, therefore, could profoundly impact patients with SCD. Animal and human data support a state of “NO resistance” in SCD patients. Human studies have shown that SCD patients have a decreased response to exogenous NO donors and that is likely due to the scavenging of NO by free plasma hemoglobin that results from ongoing hemolysis. “NO resistance” is further augmented by the increased levels of reactive oxygen species (ROS) known to occur in SCD patients. High levels of ROS favor additional hemolysis through increased oxidant stress on the sickle red blood cell and reduce NO bioavailability by inactivation of circulating NO. With the substantial human and animal data to support a role for “NO resistance” in the pathophysiology of SCD, investigation with NO-based therapy have begun. Several approaches to overcoming “NO resistance” can be devised including increasing the precursors to NO, decreasing hemolysis, direct NO donors, and decreasing oxidant stress. To date, studies evaluating arginine (NO precursor), inhaled NO, and sildenafil (NO donor) have been reported. Oral arginine showed no benefit in a large clinical trial, and a preliminary trial of inhaled NO had only minimal benefit. Sildenafil may be more promising and is under further study. Lastly, although impaired NO bioavailability has been related to a subset of patients with pulmonary hypertension, skin ulcers and priapism, it will be important to determine what impact NO has on other manifestations, such as vaso-occlusive pain episodes and whether NO modulation can also be used therapeutically in this setting.

Mechanisms of Vasculopathy in Sickle Cell Disease and Thalassemia

Many mechanisms contribute to the complex pathophysiology of sickle cell disease (SCD), with dysfunction of the vascular endothelium as a unifying theme. Specifically, hemolysis-associated low arginine and nitric oxide (NO) bioavailability, amplified by NO synthase uncoupling, elevated arginase activity, superoxide production, oxidative stress, accumulation of arginine analogs such as asymmetric dimethylarginine, ischemia-reperfusion injury, inflammation, apolipoprotein A-1 depletion, and a hypercoagulable state are significant mechanisms contributing to endothelial dysfunction. Genetic polymorphisms also influence disease severity. Clearly the variable spectrum of disease is the consequence of multiple events and genetic susceptibility that go beyond the occurrence of a single amino acid substitution in the beta globin chain of hemoglobin. Recent studies begin to demonstrate overlap among these seemingly unrelated processes. Impaired NO bioavailability represents the central feature of endothelial dysfunction, and is a common denominator in the pathogenesis of vasculopathy in SCD. The consequences of decreased NO bioavailability include endothelial cell activation, upregulation of the potent vasoconstrictor endothelin-1, vasoconstriction, platelet activation, increased tissue factor, and activation of coagulation, all of which ultimately translate into the clinical manifestations of SCD. Evidence supporting vasculopathy subphenotypes in SCD, including pulmonary hypertension, priapism, cutaneous leg ulceration, and stroke, will be reviewed and relevance to other hemolytic disorders including the thalassemia syndromes will be considered.

Identificação dos polimorfismos do gene XRCC1 em pacientes com anemia falciforme

Abstract Sickle cell disease (SCD) is an inherent disorder caused by asingle nucleotide substitution. The great variability in clinical andhematological features of SCD provides a challenge in theunderstanding of the pathophysiological mechanisms leading tothe disease. The identification of DNA polymorphisms cancontribute to understand the role of the different biomarkers andtheir relationships with the extremely variable clinical manifestationof SCD. In order to contribute to the identification of polymorphismsin SCD, we proposed to study the distribution of the DNA repairgene XRCC1 in SCD patients and healthy control individuals. Ourresults indicate that the polymorphisms of the XRCC1 variantalleles 399Gln and 194Trp were not statistically different betweenthe groups studied. We observed a tendency for the prevalence ofthe Gln/Gln genotype in SCD patients. The results from ongoinginvestigations with other polymorphisms have been elucidatingthe role of such biomarkers and their relationships with the clinicalmanifestation of SCD. Rev. bras. hematol. hemoter. 2006;