Consensus definition of essential, optimal, and suggested components of a pediatric sickle cell disease center

Sickle cell disease (SCD) requires coordinated, specialized medical care for optimal outcomes. There are no United States (US) guidelines that define a pediatric comprehensive SCD program. We report a modified Delphi consensus-seeking process to determine essential, optimal, and suggested elements of a comprehensive pediatric SCD center. Nineteen pediatric SCD specialists participated from the US. Consensus was predefined as 2/3 agreement on each element's categorization. Twenty-six elements were considered essential (required for guideline-based SCD care), 10 were optimal (recommended but not required), and five were suggested. This work lays the foundation for a formal recognition process of pediatric comprehensive SCD centers.

No child left behind: Building a comprehensive sickle cell disease care oasis in the Lake County, Indiana care desert

BACKGROUND

Sickle cell disease (SCD) leads to end-organ damage and shortened life expectancy. The second highest incidence of SCD in Indiana is in Lake County, but until 2017, there was no SCD expert within 65 miles. The Indiana Hemophilia and Thrombosis Center (IHTC) developed the Sickle Care coordination OutReach and Education (SCORE) program in 2017 to bring high-quality, guideline-based care to children with SCD.

PROCEDURE

The St. Vincent IRB deemed this retrospective analysis of SCORE clinic care from 2017 to 2020 exempt. Data on the number of transcranial Dopplers (TCD) performed, HU dosing escalation, and vaccine rates were collected along with the number of school and home visits completed.

RESULTS

Fifty-three children, adolescents, and young adults completed 288 SCORE clinic visits during the study period; over 75% completed at least three clinic visits. Mean HU dose increased significantly with SCORE clinic care. TCD screening rates increased every year starting in 2018 through 2020 when we added local care coordination. One hundred seventy-three vaccines were administered in SCORE outreach clinics. The PPSV23 vaccines had a 100% acceptance rate, and seasonal influenza had a 75.8% acceptance rate.

CONCLUSION

Access to care coordination services and local hematology specialty care alleviates barriers to care and enables comprehensive SCD care delivery to children in need. Prior to the establishment of the SCORE clinic, 75% of children in Lake County were not receiving recommended stroke screening. The SCORE clinic model demonstrates feasibility and impact when delivering on the promise of high-quality care for children with SCD.

Development and Validation of the Patient/Caregiver Reported Hydroxyurea Evaluation of Adherence for Life (HEAL) Scale

INTRODUCTION

Hydroxyurea reduces the incidence of vaso-occlusive episodes, stroke, and respiratory, cardiac, and renal damage in sickle cell disease by increasing fetal hemoglobin. However, because suboptimal adherence to hydroxyurea limits its effectiveness, understanding patient-specific barriers to hydroxyurea adherence could help improve adherence and health outcomes in patients with sickle cell disease. The aim of this single-site, prospective, IRB-approved study was to validate a 24-item patient- and caregiver-reported hydroxyurea treatment adherence questionnaire, the Hydroxyurea Evaluation of Adherence for Life (HEAL) scale.

METHODS

A sample of 24 adults with sickle cell disease and 16 caregivers of children with sickle cell disease completed the HEAL scale, and a subset of the original sample provided a second HEAL scale for test-retest reliability. HEAL scale results were validated against global adherence ratings from participants and health-care providers, records of access to pill bottles, and laboratory values for fetal hemoglobin and absolute neutrophil count.

RESULTS AND DISCUSSION

Results demonstrated excellent internal consistency for the HEAL Total score and eight (3-item) subscale scores (Dose, Remember, Plan, Cost, Understand, Effectiveness, Laboratory, and Pharmacy), as well as strong test-retest reliability for all HEAL scores except the Cost subscale. HEAL Total scores correlated significantly with validity measures, including global adherence ratings and lab values. The HEAL scale offers significant clinical potential for understanding adherence in individual sickle cell disease patients and significant research potential for characterizing adherence in persons with sickle cell disease who are treated with hydroxyurea.

How we coordinate care for uninsured children with nonmalignant hematologic disorders

Providing medical care for uninsured children with nonmalignant hematologic diagnoses presents unique challenges to medical providers and multidisciplinary staff. Financial and psychosocial stressors can hinder optimal care of the uninsured child. Maximizing coverage of medical costs through patient enrollment in state and charity care programs and capitalizing upon community partnerships can help providers achieve comprehensive care for these children. Collaboration between primary care providers, subspecialists, and multidisciplinary teams can be optimized to facilitate provision of hematology care for uninsured children. We detail our experience in establishing these collaborations to improve access to subspecialty care for children with nonmalignant hematologic disorders.

Use of dual-electron probes reveals the role of ferritin as an iron depot in ex vivo erythropoiesis

In the finely regulated process of mammalian erythropoiesis, the path of the labile iron pool into mitochondria for heme production is not well understood. Existing models for erythropoiesis do not include a central role for the ubiquitous iron storage protein ferritin; one model proposes that incoming endosomal Fe³⁺ bound to transferrin enters the cytoplasm through an ion transporter after reduction to Fe²⁺ and is taken up into mitochondria through mitoferrin-1 transporter. Here, we apply a dual three-dimensional imaging and spectroscopic technique, based on scanned electron probes, to measure Fe³⁺ in ex vivo human hematopoietic stem cells. After seven days in culture, we observe cells displaying a highly specialized architecture with anchored clustering of mitochondria and massive accumulation of nanoparticles containing high iron concentrations localized to lysosomal storage depots, identified as ferritin. We hypothesize that lysosomal ferritin iron depots enable continued heme production after expulsion of most of the cellular machinery.

Ring the Bell for Sickle Cell: Encouraging Advocacy in an Underserved Community

Sickle cell disease (SCD) was once a disease of childhood because of a limited life expectancy. Due to medical advances, it is now common for people with SCD to live into adulthood. Funding and resources for adults with SCD, however, remain limited. Adult patients would benefit from increased access to medical care, mental health care services, and workforce development. The Indiana Sickle Cell Consortium, a group of medical providers and community-based organizations, worked closely with people living with SCD and their family members to create a campaign advocating for state funding for programs for adults with SCD. This campaign culminated with the passage of a bill that provides $250,000 in funding for program development for adults with SCD. The bill also directs the Indiana Department of Health to carry out a needs assessment for people with SCD in Indiana. However, continued efforts are needed to reduce health disparities for people with SCD. The Indiana Sickle Cell Consortium will continue advocacy efforts in future legislative cycles and bring attention to the health inequities that affect people with SCD.

Hematopoietic stem cell transplant referral patterns for children with sickle cell disease vary among pediatric hematologist/oncologists' practice focus: A Sickle Cell Transplant Advocacy and Research Alliance (STAR) study

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) provides a curative therapy for children severely affected by sickle cell disease (SCD). Rejection-free survival after matched sibling donor (MSD) HSCT is very high, but adoption of HSCT as a curative SCD therapy has been slow. In this study, we assess providers' perceptions about MSD HSCT for children with variable SCD severity, and determine the influence of provider characteristics on HSCT referrals.

PROCEDURE

After our Institutional Review Board deemed the study exempt, American Society of Pediatric Hematology/Oncology Clinical Forum listserv subscribers and American Society of Hematology members who self-identified as pediatric hematologists/oncologists (PHO) were emailed a survey. Analysis was performed to describe and evaluate correlations between participant demographics (including practice focus within PHO) and likelihood of HSCT referral for each scenario.

RESULTS

Spearman's rank correlation analysis did not reveal any significant relationship between demographic characteristics except practice focus and likelihood to refer to HSCT for any scenarios. Providers focused on SCD and HSCT were more likely to refer a child who had never been admitted to the hospital or had suboptimal adherence to hydroxyurea than general PHOs. A significantly higher proportion of all respondents would refer a child with β-thalassemia major (87%) than an asymptomatic child with HbSS (47%, P < .00001) or non-HbSS variant (23%, P < .00001).

CONCLUSION

PSCD and HSCT physicians are more likely to refer for MSD HSCT in almost every condition than general PHO practitioners, likely because of increased awareness of long-term effects of SCD and safety of MSD HSCT for children with SCD.

Not all red cells sickle the same: Contributions of the reticulocyte to disease pathology in sickle cell anemia

Sickle cell anemia (SCA) is associated with morbidity and early death. While the switch from fetal to sickle hemoglobin during the first months of life results in hemolytic anemia with reticulocytosis, the role of the reticulocyte in the pathophysiology and prognosis of SCA is not well-defined. Reticulocytes have unique cytoskeletal and membrane components that allow them to be distinguished from mature sickle erythrocytes in the circulation. Reticulocytes in patients with SCA are less dense than more mature and 'sickled' erythrocytes, and have increased adhesive properties. The circulating reticulocyte number in peripheral blood may assist in predicting disease severity in SCA; characterization of patient-specific reticulocyte properties during infancy and childhood may assist in predicting therapeutic response to therapies. Here, we review the biological and clinical data regarding reticulocytes and their potential impact on SCA pathophysiology and disease severity.

Characterization of natural killer cells expressing markers associated with maturity and cytotoxicity in children and young adults with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is increasingly recognized as a red blood cell disorder modulated by abnormally increased inflammation. We have previously shown that in patients with SCD not on a disease-modifying therapy (hydroxyurea or chronic transfusions), natural killer (NK) cell numbers are increased. In the current study, we further investigated the NK cell function to determine if there was evidence of increased activation and cytotoxicity.

PROCEDURE

We conducted a cross-sectional study of 44 patients with HbSS/HbSβ⁰ thalassemia at steady state (hydroxyurea = 13, chronic transfusion = 11, no disease-modifying therapy = 20) and 23 healthy controls. Using a fresh blood sample, NK immunophenotyping was performed as follows: NK cells (CD3^- CD56⁺ lymphocytes) were evaluated for makers associated with activation (NKG2D, NKp30, NKp44, and CD69) and maturity (CD57, killer immunoglobulin-like receptors (KIR), and CD56dim). Degranulation and cytotoxicity assays were performed to evaluate NK cell function.

RESULTS

Patients with SCD who were not on disease-modifying therapy had a higher number of NK cells with an immunophenotype associated with increased cytotoxicity (NKG2D⁺ , NKp30⁺ , CD56dim⁺ , and KIR⁺ NK cells) compared with healthy controls and patients on hydroxyurea. NK cells from SCD patients not on disease-modifying therapy demonstrated significantly increased cytotoxicity (measured by assaying NK cell killing of the K562 cell line) compared with healthy controls (P = 0.005). Notably, NK cell cytotoxicity against K562 cells in the hydroxyurea or chronic transfusion patients was not significantly different from that in healthy controls.

CONCLUSION

SCD is associated with increased NK cell function as well as increased NK cell numbers, which appears to be normalized with disease-modifying therapy.

Clinical features of children, adolescents, and adults with coexisting hypermobility syndromes and von Willebrand disease

We present five patients with coexistent von Willebrand disease (VWD) and Ehlers-Danlos syndrome and 21 with VWD and joint hypermobility. Females outnumbered males ten to three, Beighton scores were documented in 58% (15 of 26 patients), and several patients experienced moderately severe bleeding. We believe coexistent hypermobility disorder with VWD potentially affects bleeding severity and want to raise awareness among hematologists. Evaluation by geneticists is recommended because of the varying complexities observed across the disease spectrum, and the availability of new genetic tests should lead to more accurate diagnoses for the various hypermobility disorders.

Access to hematopoietic stem cell transplant for patients with sickle cell anemia

Hematopoietic stem cell transplantation (HSCT) is a curative therapy for patients with phenotypically severe sickle cell anemia, and survival rates following matched-sibling HSCT are very high. However, despite cure rates much higher than HSCT for malignant diseases, the field has been slow to adopt this treatment modality for sickle cell anemia. This article explores some of the social forces that may contribute to this dichotomy.

Diverse manifestations of acute sickle cell hepatopathy in pediatric patients with sickle cell disease: A case series

The hepatic complications of sickle cell disease (SCD) are associated with increased morbidity and mortality in adults; children usually survive but may suffer significant sequelae. Few diagnostic tools differentiate the various hepatic manifestations of SCD. Why patients exhibit one hepatic pathology versus another is unclear. We report four pediatric patients with hemoglobin SS disease with diverse manifestations of acute hepatic involvement including acute sickle hepatic crisis, hepatic sequestration, sickle cell intrahepatic cholestasis, and a non-SCD cause of hepatopathy in a patient with viral hepatitis. These complications require a systematic approach to extensive evaluation and coordinated multidisciplinary care.

Treatment Options for Sickle Cell Disease

Sickle cell disease (SCD) complications begin with the polymerization of sickle hemoglobin (HbS). Thus, SCD therapies are focused on preventing HbS production or reducing the circulating amount of HbS. Hydroxyurea treatment has become more widespread, whereas the number of evidence-based indications for erythrocyte transfusion is small. Hematopoietic stem cell transplant is a curative option for SCD but less than 25% of patients have a suitable donor. This article focuses on supportive and preventive care improvements and the benefits of hydroxyurea. Indications for erythrocyte transfusion, hematopoietic stem cell transplant, and gene therapy trials are also summarized.

Early initiation of inhaled corticosteroids does not decrease acute chest syndrome morbidity in pediatric patients with sickle cell disease

Acute chest syndrome (ACS) is a leading cause of mortality in patients with sickle cell disease (SCD). Systemic corticosteroids decrease ACS severity, but the risk of readmission for vaso-occlusive crises (VOC) has limited their use. The efficacy of inhaled corticosteroids (ICS) as a safer alternative is currently unknown. An observational, historic cohort study compared patients with SCD with ACS who received ICS at admission (ICS) to those who did not (non-ICS). Outcome measures included rates of transfusion, oxygen requirement, BiPAP initiation, PICU transfer, intubation, readmission, hospital cost, and length of stay. One hundred twenty patients with SCD (55 non-ICS, 65 ICS) were included. A significantly higher proportion of the non-ICS group had bilateral infiltrates, but fewer had asthma. More children in the ICS group had BiPAP initiated, however transfer to the PICU, intubation, transfusion rates, oxygen requirement, hospital cost, length of stay, and readmission rates did not differ between groups. Regression analysis did not reveal any differences in outcomes, nor were outcomes changed when patients were separated based on the presence or absence of asthma. In this observational cohort study, ICS did not demonstrate a significant reduction in ACS morbidity, though ICS use should be studied in a prospective manner.

Cranial epidural hematomas: A case series and literature review of this rare complication associated with sickle cell disease

BACKGROUND

Patients with sickle cell disease (SCD) may experience many complications of the central nervous system (CNS) including stroke, silent cerebral infarcts, and neuropsychological deficits. Cranial epidural hematoma is a rare but potentially serious complication.

PROCEDURE

Case series of cranial epidural hematomas in children with SCD from three different institutions is considered, along with a literature review of cranial epidural hematomas in this population.

RESULTS

Seven children with SCD with cranial epidural hematomas were identified from three different institutions. All patients were male and the age at presentation ranged from 10 to 18 years. Two patients presented with headache (28.6%), while the rest had no neurologic symptoms at presentation. Four patients required urgent neurosurgical intervention (57.1%) and one patient died (14.3%). A literature review identified 18 additional cases of cranial epidural hematomas in children with SCD. Of these, treatment ranged from supportive care to neurosurgical intervention. Twelve patients completely recovered (66.7%), one patient had long-term cognitive impairment (5.6%), and four patients died (22.2%). Combined with our data, cranial epidural hematomas have a mortality rate of 20.0%.

CONCLUSIONS

Although rare, cranial epidural hematoma can be fatal and should be considered in patients with acute neurological symptoms.

Homozygous α-thalassemia: Challenges surrounding early identification, treatment, and cure

The prognosis for homozygous α-thalassemia is changing. Prenatal diagnosis and intrauterine transfusions (IUT) reduce maternofetal morbidity and mortality; hematopoietic stem cell transplant (HSCT) is curative. Empiric evidence to support IUT and HSCT to treat homozygous α-thalassemia is lacking. The first case of curative HSCT for homozygous α-thalassemia was reported in 1997. Nearly 20 years later, five additional reports are published. We review the literature and report an institutional experience with three homozygous α-thalassemia patients. The first died shortly after birth. The second underwent HSCT after years of chronic transfusion therapy. The third benefited from IUT and HSCT. These cases exemplify the varied outcomes associated with this condition.

Pediatric sickle cell disease: past successes and future challenges

Once a fatal disease of childhood, more than 95% of patients born today with sickle cell disease (SCD) in developed countries are expected to survive into adulthood, largely because of improvements in supportive and preventive care (newborn screening, penicillin prophylaxis, transcranial Doppler (TCD) screening). Hydroxyurea (HU) therapy, the only oral medication currently available to prevent SCD complications, has become more widespread over the past 20 y. The NHLBI recommends that HU be offered to all patients with HbSS beginning at 9 mo of age, and the recently published Abnormal TCD with Transfusions Changing to HU (TWiTCH) trial has shown HU as an acceptable alternative to transfusion therapy for patients at high risk of stroke. While hematopoietic stem cell transplant (HSCT) is a curative option for SCD, less than 25% of patients have a suitable donor. Alternative stem cell sources from unrelated donors and haplo-identical donors are currently under investigation as are gene therapy trials. This review will focus on early efforts to elucidate SCD pathophysiology as well as supportive and preventive care improvements. Findings from recent multi-center studies (Silent Infarct Transfusion (SIT) Trial and TWiTCH) will be summarized. Finally, HSCT trials and gene therapy will be reviewed.

Examination of Reticulocytosis among Chronically Transfused Children with Sickle Cell Anemia

Sickle cell anemia (SCA) is an inherited hemolytic anemia with compensatory reticulocytosis. Recent studies have shown that increased levels of reticulocytosis during infancy are associated with increased hospitalizations for SCA sequelae as well as cerebrovascular pathologies. In this study, absolute reticulocyte counts (ARC) measured prior to transfusion were analysed among a cohort of 29 pediatric SCA patients receiving chronic transfusion therapy (CTT) for primary and secondary stroke prevention. A cross-sectional flow cytometric analysis of the reticulocyte phenotype was also performed. Mean duration of CTT was 3.1 ± 2.6 years. Fifteen subjects with magnetic resonance angiography (MRA) -vasculopathy had significantly higher mean ARC prior to initiating CTT compared to 14 subjects without MRA-vasculopathy (427.6 ± 109.0 K/μl vs. 324.8 ± 109.2 K/μl, p<0.05). No significant differences in hemoglobin or percentage sickle hemoglobin (HbS) were noted between the two groups at baseline. Reticulocyte phenotyping further demonstrated that the percentages of circulating immature [CD36(+), CD71(+)] reticulocytes positively correlated with ARC in both groups. During the first year of CTT, neither group had significant reductions in ARC. Among this group of children with SCA, cerebrovasculopathy on MRA at initiation of CTT was associated with increased reticulocytosis, which was not reduced after 12 months of transfusions.

Effectiveness of red blood cell exchange, partial manual exchange, and simple transfusion concurrently with iron chelation therapy in reducing iron overload in chronically transfused sickle cell anemia patients

BACKGROUND

Chronic transfusion therapy (CTT) is indicated for stroke prevention in children with sickle cell anemia (SCA) and is complicated by iron overload and alloimmunization. CTT is performed by simple transfusion (ST), partial manual exchange (PME), or erythrocytapheresis (RCE). Although small case series have demonstrated RCE in combination with iron chelation therapy stabilizes and/or decreases ferritin, there are no reports comparing the effect of ST, PME, and RCE on liver iron concentration (LIC). CTT modality effect on serum ferritin and LIC were compared in SCA patients on iron chelation, with hemoglobin (Hb)S goal of 30%.

STUDY DESIGN AND METHODS

Medical records of SCA patients on CTT and deferasirox (≥25 mg/kg/day) were retrospectively reviewed. Mean HbS%, change in ferritin and LIC, and alloimmunization rate were determined for each CTT group.

RESULTS

Twenty-eight patients were included; six crossed over (one from ST to PME, one from ST to PME then to RCE, three from ST to RCE, and one from PME to RCE) to include 36 transfusion modality intervals. Median pretransfusion HbS% levels were 32.7% (ST), 36.2% (PME), and 34.7% (RCE; p = 0.732). Median ferritin changes were +15 (-17 to +45), +38 (+24 to +105), and -91 (-141 to -48) ng/mL/month (p = 0.003), and median LIC changes (available in 22 patient transfusion modality intervals) were +1.3 (-1.6 to +4.3), +2.3 (-6.5 to +8.9), and -5.7 (-10.7 to -0.5) mg/g/year (p = 0.024) in ST, PME, and RCE, respectively. There was no significant difference in alloimmunization rate between ST/PME and RCE groups.

CONCLUSION

We recommend RCE plus chelation as an effective method for reducing iron overload, while maintaining HbS at 30% to 35%.

Early Reticulocytosis and Anemia Are Associated with Abnormal and Conditional Transcranial Doppler Velocities in Children with Sickle Cell Anemia

OBJECTIVE

To improve prediction of sickle cell anemia severity at an early age, we evaluated whether absolute reticulocyte count (ARC) or hemoglobin (Hb) levels during early infancy (2-6 months of age) in patients with sickle cell anemia predict the risk of later developing an abnormal (abTCD) or conditional (cdTCD) Transcranial Doppler (TCD).

STUDY DESIGN

We used chart review to identify 121 consecutive patients who underwent TCD screening and had steady state ARC and Hb levels recorded between 2 and 6 months of age. Cox regression analysis was used to determine the relationship between ARC, Hb levels, and risk of developing cdTCD/abTCD over time.

RESULTS

Mean ARC in early infancy was highest and mean Hb lowest in those children with abTCDs and cdTCDs. Cox regression analysis revealed that those subjects with an ARC ≥200 K/μL in early infancy had nearly 3 times the risk of having an abTCD/cdTCD than the group with an ARC <200 K/μL, and patients with a Hb <8.5 g/dL had 2.7 times the risk of having an abTCD/cdTCD.

CONCLUSIONS

These data suggest that both elevated ARC and low baseline Hb during early infancy are associated with an increased risk of developing a cdTCD or abTCD later in childhood.

Provider Perspective on Integrative Medicine for Pediatric Sickle Cell Disease-related Pain

OBJECTIVE

Integrative medicine (IM) approaches are sometimes used to manage sickle cell disease (SCD)-related pain. The purpose of this research is to (1) understand provider perspective towards the use of IM for pain in children with SCD at a large urban children's hospital and (2) provide recommendations on how to better promote IM for children and adolescents with SCD.

METHODS

After approval from the institutional review board, a qualitative case study approach was used with criterion-type purposeful sampling to select providers from the division of hematology to adequately inform the study. Semistructured interviews were completed using audiotape to facilitate transcription. NVivo 10 analytic software (QSR International Pty Ltd, Doncaster, Victoria, Australia) was used to organize data into themes to answer the study questions.

RESULTS

Ten provider interviews were completed. Attitudes were generally positive, and most providers felt that IM is generally helpful. All providers reported that they do not optimally use integrative therapies for children with SCD. The barriers uncovered focused on lack of process for integration of IM, specifically that IM resources seem transient and based on short-term funding. Provider attitude towards CAM is generally positive, but provider comfort level is highly variable. No providers are completely comfortable with their knowledge base about IM, and increased knowledge is desired.

CONCLUSIONS

Creation of protocols and processes to incorporate IM into management plans for patients with SCD could help to promote its use. Education of providers about utility and efficacy of IM for SCD-related pain and about existing resources would aid in promotion of IM for children with SCD.

Absolute Reticulocyte Count Acts as a Surrogate for Fetal Hemoglobin in Infants and Children with Sickle Cell Anemia

Hemoglobin switching is largely complete in humans by six months of age. Among infants with sickle cell anemia (HbSS, SCA), reticulocytosis begins early in life as fetal hemoglobin (HbF) is replaced by sickle hemoglobin (HbS). The objective of this study was to determine if absolute reticulocyte count (ARC) is related to HbF levels in a cohort of pediatric SCA patients. A convenience sample of 106 children with SCA between the ages of 1 month and 20 years who were not receiving hydroxyurea or monthly blood transfusions were enrolled in this observational study. Hematologic data, including ARC and HbF levels, were measured at steady state. F-cells were enumerated by flow cytometry. Initial studies compared infants with ARC greater than or equal to 200 K/μL (ARC ≥ 200) based upon the previously reported utility of this threshold as a predictive marker for SCA severity. Mean HbF and F-cell levels were significantly lower in the ARC ≥ 200 group when compared to the ARC < 200 group. Both HbF and F-cell percentages were negatively correlated to ARC in infants and in children between the ages of 1 and 9 years. However, the inverse relationship was lost after the age of 10 years. Overall, decreased expression and distribution of HbF during childhood SCA is well-correlated with increased reticulocyte production and release into the peripheral blood. As such, these data further support the clinical use of reticulocyte enumeration as a disease severity biomarker for childhood sickle cell anemia.

Current attitudes of parents and patients toward hematopoietic stem cell transplantation for sickle cell anemia

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only available cure for sickle cell anemia (SCA). HSCT-associated risks are one of many barriers to its widespread use for SCA. The study objective was to assess parent and patient perceptions of HSCT in the era of more widespread knowledge about HSCT for SCA.

PROCEDURE

We surveyed parents of children with SCA and adolescents with SCA using the standard reference gamble paradigm. Survey responses between Africans (A) and African Americans (AA) and between parents and adolescents were compared.

RESULTS

Seventy-two percent (64/89) of the respondents were willing to accept ≥ 5% risk of mortality, while 57% said they would accept a risk of ≥ 10% of graft versus host disease (GVHD). Twenty-two percent were unwilling to accept any risk of mortality or GVHD. Risk averseness did not differ between A or AA respondents. Fifty-six percent of respondents were willing to accept infertility post-HSCT.

CONCLUSIONS

These data suggest that the majority of parents and adolescents are willing to accept the current risks associated with matched sibling HSCT for SCA. However, there continue to be significant numbers of parents and adolescents who are unwilling to accept any risk of HSCT-associated mortality or GVHD.

Kaposiform lymphangiomatosis: unifying features of a heterogeneous disorder

Kaposiform lymphangiomatosis (KLA) is a rare proliferation of abnormal lymphatic vessels often complicated by pleural/pericardial effusions and a consumptive coagulopathy that may lead to life threatening hemorrhage. Establishing the diagnosis is challenging due to the clinical heterogeneity and variable findings in laboratory values, radiographic features, and pathologic characteristics. We report three patients who had slowly progressive symptoms and presented with pleural or pericardial effusions, evidence of a consumptive coagulopathy and anemia. Despite being a rare and challenging diagnosis, KLA should be considered in patients presenting with non-specific indolent symptoms, pleural or pericardial effusions and laboratory evidence of a consumptive coagulopathy.

Health-related quality of life in children with sickle cell anemia: impact of blood transfusion therapy

The completion of the Multicenter Silent Infarct Transfusion Trial demonstrated that children with pre-existing silent cerebral infarct and sickle cell anemia (SCA) who received regular blood transfusion therapy had a 58% relative risk reduction of infarct recurrence when compared to observation. However, the total benefit of blood transfusion therapy, as assessed by the parents, was not measured against the burden of monthly blood transfusion therapy. In this planned ancillary study, we tested the hypothesis that a patient centered outcome, health-related quality of life (HRQL), would be greater in participants randomly assigned to the blood transfusion therapy group than the observation group. A total of 89% (175 of 196) of the randomly allocated participants had evaluable entry and exit HRQL evaluations. The increase in Change in Health, measured as the child's health being better, was significantly greater for the transfusion group than the observation group (difference estimate = -0.54, P ≤ 0.001). This study provides the first evidence that children with SCA who received regular blood transfusion therapy felt better and had better overall HRQL than those who did not receive transfusion therapy.

Red blood cell alloimmunization is influenced by recipient inflammatory state at time of transfusion in patients with sickle cell disease

Sickle cell disease (SCD) patients are at increased risk of red blood cell (RBC) alloimmunization. Recipient inflammatory state at time of transfusion has been shown to regulate alloimmunization in murine models, but evidence is lacking in SCD patients. We retrospectively studied a cohort of alloimmunized SCD patients to determine the influence of pro-inflammatory SCD-related complications at time of transfusion on alloimmunization. For each transfusion, the presence of pro-inflammatory state, degree of RBC antigen matching, unit age, storage solution and alloantibody detection date were ascertained. Transfusion-associated pro-inflammatory events were compared between transfusions resulting and not resulting in new alloantibodies. Univariate analysis and multivariate logistic regression were performed. Fifty-two patients received 3166 pre-storage leuco-reduced transfusions of which 128 resulted in alloantibodies. Transfusions during inflammatory events were associated with increased alloantibody risk on univariate and multivariate analysis; acute chest syndrome and vaso-occlusive crisis showed strongest associations with alloimmunization. Increased antigen matching demonstrated a protective effect on alloimmunization (univariate and multivariate analysis). Although an association was seen between citrate-phosphate-dextrose (adenine) stored units and alloimmunization on univariate analysis, no effect was found on multivariate analysis. Identifying recipient pro-inflammatory states at time of transfusion that promote alloimmunization can impact RBC unit selection decisions for SCD patients at risk for alloimmunization.

Reticulocytosis and anemia are associated with an increased risk of death and stroke in the newborn cohort of the Cooperative Study of Sickle Cell Disease

Prior analyses of the Cooperative Study of Sickle Cell Disease (CSSCD) newborn cohort identified elevated white blood cell (WBC) count, low baseline hemoglobin and dactylitis between the ages of 1 and 2 years as markers of severe disease. Reticulocytosis was also associated with severe disease. Here, we further analyzed data collected on enrolled CSSCD infants for the predictive value of those markers for stroke and death later in life. Three hundred fifty-four CSSCD subjects were identified who had absolute reticulocyte counts (ARC) measured during infancy (2 to 6 months of age). Infants with higher ARC had significantly increased risk of stroke or death during childhood; lower hemoglobin levels also increased the risk but to a lesser degree than ARC. WBC levels and dactylitis were not predictive of death or stroke. These data suggest that reticulocytosis among asymptomatic infants with sickle cell anemia is associated with an increased risk of death or stroke during childhood.

An educational symposium for patients with sickle cell disease and their families: results from surveys of knowledge and factors influencing decisions about hematopoietic stem cell transplant

BACKGROUND

The only available cure for sickle cell disease (SCD) is hematopoietic stem cell transplant (HSCT). One important barrier to HSCT in SCD is lack of patient and family knowledge.

PROCEDURE

To improve awareness of HSCT as a curative option for SCD, we hosted half-day educational symposia in 2011 and 2012. Symposia included didactic lectures by HSCT experts, small group sessions, and question and answer sessions with SCD patients and their families who had undergone HSCT. In 2011, we distributed anonymous pre- and post-symposium knowledge tests to determine how much attendees had learned about transplant. In 2012, we asked attendees to rate the importance of various medical and psychosocial factors in the decision to pursue HSCT.

RESULTS

Results from 2011 showed that knowledge about HSCT increased significantly after the symposium. Concern about the risk of transplant decreased slightly, but not significantly, following the symposium, and the majority of attendees expressed a desire to speak with physicians further about HSCT. In 2012, families reported that risk of death, prevention of SCD complications, and risk of serious complications were the most important considerations for their decisions about HSCT.

CONCLUSIONS

A half-day symposium for SCD patients and their families can increase knowledge about HSCT. Education about risks and benefits of HSCT is key, as families consider these medical factors to be most important to their decision to pursue transplant. Our symposia can be replicated across the country to increase knowledge about HSCT for SCD and impact the number of patients who pursue HSCT.

Increased reticulocytosis during infancy is associated with increased hospitalizations in sickle cell anemia patients during the first three years of life

Objective

Among older children with sickle cell anemia, leukocyte counts, hemoglobin, and reticulocytosis have previously been suggested as disease severity markers. Here we explored whether these blood parameters may be useful to predict early childhood disease severity when tested in early infancy, defined as postnatal ages 60–180 days.

Study Design

Data from fifty-nine subjects who were followed at Children’s National Medical Center’s Sickle Cell Program for at least three years was retrospectively analyzed. Comparisons were made between white blood cell counts, hemoglobin and reticulocyte levels measured at ages 60–180 days and the clinical course of sickle cell anemia during infancy and childhood.

Results

A majority of subjects had demonstrable anemia with increased reticulocytosis. Only increased absolute reticulocyte levels during early infancy were associated with a significant increase in hospitalization during the first three years of life. Higher absolute reticulocyte counts were also associated with a markedly shorter time to first hospitalizations and a four-fold higher cumulative frequency of clinical manifestations over the first three years of life. No significant increase in white blood cell counts was identified among the infant subjects.

Conclusions

These data suggest that during early infancy, increased reticulocytosis among asymptomatic SCA subjects is associated with increased severity of disease in childhood.

Sickle cell disease in children

Early identification of infants with sickle cell disease (SCD) by newborn screening, now universal in all 50 states in the US, has improved survival, mainly by preventing overwhelming sepsis with the early use of prophylactic penicillin. Routine transcranial Doppler screening with the institution of chronic transfusion decreases the risk of stroke from 10% to 1% in paediatric SCD patients. Hydroxyurea decreases the number and frequency of painful crises, acute chest syndromes and number of blood transfusions in children with SCD. Genetic research continues to be driven toward the prevention and ultimate cure of SCD before adulthood. This review focuses on clinical manifestations and therapeutic strategies for paediatric SCD as well as the evolving topic of gene-focused prevention and therapy.

Expression patterns of fetal hemoglobin in sickle cell erythrocytes are both patient- and treatment-specific during childhood

BACKGROUND

Treatment-associated fetal hemoglobin (HbF) expression patterns in children with sickle cell disease (SCD) have not been fully described. The objective of this study was to compare HbF expression profiles (HbF and F-cells) in the peripheral blood of pediatric SCD patients receiving hydroxyurea (HU), chronic transfusions (Tx) or no chronic therapy (Ctrl).

PROCEDURE

Peripheral blood samples were collected from SCD patients between 1 month and 21 years of age and immunostained with anti-HbF and anti-HbA antibodies. Erythrocytes containing HbF (F-cells) were enumerated with this dual staining method. HbF was measured using chromatography (HPLC).

RESULTS

Blood from 44 Ctrl patients ≤ 4 years of age was compared with that from older children (50 Ctrl, 17 HU, 17 Tx). Among the older children, the percentage of both HbF and F-cells in the Tx group was significantly decreased compared to the control (HbF 5.4 ± 4.2% vs. 11.0 ± 7.2%, P = 0.003; F-cells 30.2 ± 16.3% vs. 43.8 ± 20.4%, P = 0.0071). While the distribution of F-cells was significantly increased in the HU group (56.3 ± 17.1% vs. 43.8 ± 20.4%, P = 0.016), the increase in HbF was less robust (14.7 ± 6.4% vs. 11.0 ± 7.2%, P = 0.051). Positive correlations of HbF and F-cell distributions were noted in all groups (P < 0.0001 for all groups). In serial samples from individual patients, relatively static patterns of HbF and F-cell distribution were noted.

CONCLUSION

Pediatric SCD patients possess distinct patterns of HbF switching and silencing in peripheral blood erythrocytes. Thereafter, erythrocyte HbF expression level and distribution are maintained with both patient- and treatment-specific patterns that may be useful for predicting the need or response to HbF-modulating therapy.