Clinical outcomes of children and adolescents with sickle cell disease and COVID-19 infection: A year in review at a metropolitan tertiary pediatric hospital.

Background: COVID-19 was declared a global pandemic in March 2020. Early reports were primarily in adults, and sickle cell disease (SCD) was classified as a risk factor for severe COVID-19 disease. However, there are a limited number of primarily multi-center studies reporting on the clinical course of pediatric patients with SCD and COVID-19. Methods: We conducted an observational study of all patients with SCD diagnosed with COVID-19 at our institution between March 31, 2020, and February 12, 2021. Demographic and clinical characteristics of this group were collected by retrospective chart review. Results: A total of 55 patients were studied, including 38 children and 17 adolescents. Demographics, acute COVID-19 clinical presentation, respiratory support, laboratory findings, healthcare utilization, and SCD modifying therapies were comparable between the children and adolescents. Seventy-three percent (N = 40) of all patients required emergency department care or hospitalization. While 47% (N = 26) were hospitalized, only 5% (N = 3) of all patients required intensive care unit admission. Patients frequently had concurrent vaso-occlusive pain crisis (VOC) (N = 17, 43%) and acute chest syndrome (ACS) (N = 14, 35%). Those with ACS or an oxygen requirement had significantly higher white blood cell count, lower nadir hemoglobin, and higher D-dimers, supporting a pro-inflammatory and coagulopathic picture. Non-hospitalized patients were more likely to be on hydroxyurea than hospitalized patients (79 vs. 50%, p = 0.023). Conclusion: Children and adolescent patients with SCD and acute COVID-19 often present with ACS and VOC pain requiring hospital-level care. Hydroxyurea treatment appears to be protective. We observed no mortality despite variable morbidity.

Optimising the screening for haemoglobinopathies in pregnancy planning.

Haemoglobinopathies are among the most common inherited disorders around the world. In the United States the diagnosis of haemoglobinopathy or a carrier state is made by universal newborn screening. However, many individuals of childbearing age do not know they are a haemoglobinopathy carrier. Screening for common haemoglobinopathies is generally offered as a part of pregnancy planning so that prospective parents can be counselled regarding the risk of having a child with a haemoglobinopathy. Multiple tests exist to screen patients for presence of haemoglobinopathy carrier or disease state; however, it is crucial to order and interpret the results correctly to appropriately counsel couples. In this case series, we describe clinical scenarios where prospective parents were surprised to unexpectedly have a child with sickle cell disease, a haemoglobinopathy that causes severe clinical complications. Through these cases we demonstrate that deficiencies in testing can occur at different levels which may lead to incorrect estimation of the risk of having a child affected by a haemoglobinopathy. Consultation with a haematologist, laboratory medicine specialist, or genetic counsellor should be considered to select the appropriate test and interpret its results.

Long-Term Organ Function After HCT for SCD: A Report From the Sickle Cell Transplant Advocacy and Research Alliance.

Hematopoietic cell transplantation (HCT) is an established cure for sickle cell disease (SCD) supported by long-term survival, but long-term organ function data are lacking. We sought to describe organ function and assess predictors for dysfunction in a retrospective cohort (n = 247) through the Sickle cell Transplant Advocacy and Research alliance. Patients with <1-year follow-up or graft rejection/second HCT were excluded. Organ function data were collected from last follow-up. Primary measures were organ function, comparing pre- and post-HCT. Bivariable and multivariable analyses were performed for predictors of dysfunction. Median age at HCT was 9.4 years; the majority had HbSS (88.2%) and severe clinical phenotype (65.4%). Most received matched related (76.9%) bone marrow (83.3%) with myeloablative conditioning (MAC; 57.1%). Acute and chronic graft-versus-host disease (GVHD) developed in 24.0% and 24.8%. Thirteen patients (5.3%) died ≥1 year after HCT, primarily from GVHD or infection. More post-HCT patients had low ejection or shortening fractions than pre-HCT (0.6% â†’ 6.0%, P = .007 and 0% â†’ 4.6%, P = .003). The proportion with lung disease remained stable. Eight patients (3.2%) had overt stroke; most had normal (28.3%) or stable (50.3%) brain magnetic resonance imaging. On multivariable analysis, cardiac dysfunction was associated with MAC (odds ratio [OR] = 2.71; 95% confidence interval [CI], 1.09-6.77; P = .033) and severe acute GVHD (OR = 2.41; 95% CI, 1.04-5.62; P = .041). Neurologic events were associated with central nervous system indication (OR = 2.88; 95% CI, 2.00-4.12; P < .001). Overall organ dysfunction was associated with age ≥16 years (OR = 2.26; 95% CI, 1.35-3.78; P = .002) and clinically severe disease (OR = 1.64; 95% CI, 1.02-2.63; P = .043). In conclusion, our results support consideration of HCT at younger age and use of less intense conditioning.

Reduction in vaso-occlusive events following stem cell transplantation in patients with sickle cell disease.

Hematopoietic stem cell transplantation (HSCT) is potentially curative for patients with sickle cell disease (SCD). Patients with stable donor engraftment after allogeneic HSCT generally do not experience SCD-related complications; however, there are no published data specifically reporting the change in vaso-occlusive events (VOE) after HSCT. Data regarding the number of VOEs requiring medical attention in the 2 years before allogeneic HSCT were compared with the number of VOEs in the 2 years (0-12 months and 12-24 months) after allogeneic HSCT in patients with SCD. One-hundred sixty-three patients with SCD underwent allogeneic HSCT between 2005 and 2019. The average age at the time of HSCT was 21 years (range, 7 months - 64 years). Most patients underwent nonmyeloablative conditioning (75% [N = 123]) and had a matched sibling donor (72% [N = 118]). The mean number of VOEs was reduced from 5.6 (range, 0-52) in the 2 years before HSCT to 0.9 (range, 0-12) in the 2 years after HSCT (P < .001). Among the post-HSCT events, VOE was more frequent during the first 12 months (0.8 [range, 0-12]) than at 12 to 24 months after HSCT (0.1 [range, 0-8) (P < .001)). In patients who had graft rejection (12%, N = 20), VOEs were reduced from 6.6 (range, 0-24) before HSCT to 1.1 (range, 0-6) and 0.8 (range, 0-8) at 0 to 12 months and 12 to 24 months after HSCT, respectively (P < .001). VOEs requiring medical care were significantly reduced after allogeneic HSCT for patients with SCD. These data will inform the development of novel autologous HSCT gene therapy approaches.

Amino acid signature during sickle cell pain crisis shows significant alterations related to nitric oxide and energy metabolism.

Nitric oxide depletion secondary to arginase induced arginine deficiency has been shown to be important in the pathophysiology of vaso-occlusion in sickle cell pain crisis. Our objective of this study was to perform a comprehensive amino acid evaluation during sickle cell pain crisis. In a total of 58 subjects (29 in steady-state sickle cell disease and 29 with sickle cell pain crisis), the amino acids related to nitric oxide pathway was significantly decreased during sickle cell pain crisis compared to steady-state sickle cell disease: arginine (p = 0.001), citrulline (p = 0.012), and ornithine (p = 0.03). In addition, the amino acids related to energy metabolism was significantly decreased during a pain crisis: asparagine (p < 0.001), serine (p = 0.002), histidine (p = 0.017), alanine (p = 0.004), tyrosine (p = 0.012), methionine (p = 0.007), cystine (p = 0.016), isoleucine (p = 0.016) and lysine (p = 0.006). The amino acid related to oxidative stress were significantly higher during a sickle cell pain crisis (glutamic acid (p < 0.001). Furthermore, multivariate analysis with partial least squares-discriminant analysis (PLS-DA) showed that deficiencies of the amino acids arginine, asparagine, citrulline, methionine and alanine were the most important related to sickle cell pain crisis.

Fertility after Curative Therapy for Sickle Cell Disease: A Comprehensive Review to Guide Care.

Curative therapy for sickle cell disease (SCD) currently requires gonadotoxic conditioning that can impair future fertility. Fertility outcomes after curative therapy are likely affected by pre-transplant ovarian reserve or semen analysis parameters that may already be abnormal from SCD-related damage or hydroxyurea treatment. Outcomes are also likely affected by the conditioning regimen. Conditioning with myeloablative busulfan and cyclophosphamide causes serious gonadotoxicity particularly among post-pubertal females. Reduced-intensity and non-myeloablative conditioning may be acutely less gonadotoxic, but more short and long-term fertility outcome data after these approaches is needed. Fertility preservation including oocyte/embryo, ovarian tissue, sperm, and experimental testicular tissue cryopreservation should be offered to patients with SCD pursing curative therapy. Regardless of HSCT outcome, longitudinal post-HSCT fertility care is required.

Preventing antibody positive delayed hemolytic transfusion reactions in sickle cell disease: Lessons learned from a case.

INTRODUCTION: Red blood cell (RBC) transfusions are important in the management of patients with sickle cell disease (SCD). However, a potentially catastrophic complication of transfusion in this population is the delayed hemolytic transfusion reaction (DHTR). The pathophysiology of all DHTRs is not understood, but some are known to be caused by an anamnestic resurgence of RBC alloantibodies. CASE PRESENTATION: A child with SCD transfused for acute chest syndrome re-presented a week after hospital discharge with severe anaemia, hemolysis, and a newly detected anti-E. This patient had been previously transfused years ago at an outside institution and the anti-E had not been previously documented. DISCUSSION: The presented case of an antibody positive DHTR illustrates several concepts critical to the prevention of this complication. RBC alloantibodies must be detected and this information must be shared. Prophylactic C/c, E/e, K antigen matching is helpful for patients with SCD, but systems must be in place to identify these patients. Patients transfused at multiple different hospitals are especially at risk for this complication and efforts are needed to prevent them from suffering a DHTR.

Low Rates of Cerebral Infarction after Hematopoietic Stem Cell Transplantation in Patients with Sickle Cell Disease at High Risk for Stroke.

Hematopoietic stem cell transplantation (HSCT) can be curative for sickle cell disease (SCD). SCD patients with cerebrovascular disease are often referred for HSCT. The objective of this study was to describe neurologic outcomes after HSCT in patients with pre-existing SCD and cerebrovascular comorbidity. Patients with SCD treated with HSCT at a single center between 1996 and 2019 were identified. Patients with cerebral ischemia and/or vasculopathy before undergoing HSCT were included. Patients with graft failure were excluded. The cohort was divided into 3 groups: symptomatic stroke, vasculopathy without symptomatic stroke, and isolated silent cerebral infarction (SCI). Magnetic resonance imaging/angiography and neurologic assessments pre- and post-HSCT were analyzed to assess outcomes. In a cohort of 44 patients, there were 25 with symptomatic infarction, 10 with vasculopathy, and 9 with isolated SCI. Post-HSCT ischemic injury (2 symptomatic strokes, 2 SCIs) was identified in 4 patients, all with previous symptomatic infarction. Within this group (n = 25), the post-HSCT incidence of subsequent symptomatic infarction was 1.6 events/100 patient-years, and SCIs occurred at a rate of 2.2 events/100 patient-years. No patient had progression of vasculopathy post-HSCT. Our data show a low incidence of new ischemic injury after successful HSCT for SCD. Patients with a history of both symptomatic stroke and vasculopathy are at greatest risk for post-HSCT ischemic injury.

Impact of universal irradiation on chronic transfusion for sickle cell disease.

BACKGROUND: Irradiation of blood products prevents transfusion-associated graft-versus-host disease, but most patients do not require this modification which could have an adverse impact on transfusion outcomes. We hypothesized that irradiation may increase transfusion requirements for patients with sickle cell disease (SCD) receiving chronic transfusion. STUDY DESIGN AND METHODS: Our pediatric hospital implemented a new policy of universal blood product irradiation in May 2018. We conducted a retrospective chart review of patients with SCD receiving chronic red blood cell (RBC) transfusion throughout the year before and after institution of this policy. The primary outcome was the change in RBC transfusion volume per patient weight transfused during the pre- vs. post- universal irradiation period. Secondary outcomes were the change in median pretransfusion laboratory values. RESULTS: Among 17 patients, 8 (47%) received more RBCs the year before irradiation and 9 (53%) received more the year after irradiation. Implementation of universal irradiation did not significantly increase transfusion volumes needed to clinically manage this population (median change +1.7 ml/kg/year, p = .54). Additionally, there were no significant changes in absolute reticulocyte count, hemoglobin, hemoglobin S%, white blood cell count, lactate dehydrogenase, total bilirubin, serum potassium, and ferritin during the two time periods. CONCLUSION: In a cohort of patients with SCD receiving simple chronic transfusion, irradiation did not impact transfusion requirements or pertinent pretransfusion laboratory values. Irradiation does not appear to have clinically significant consequences for SCD chronic transfusion management.

Screening for new red blood cell alloantibodies after transfusion in patients with sickle cell disease.

BACKGROUND: Patients with sickle cell disease (SCD) are frequent recipients of red blood cell (RBC) transfusions and are at risk for RBC alloimmunization. RBC alloimmunization is diagnosed by identifying RBC alloantibodies as part of pre-transfusion testing, but this testing fails to detect alloantibodies that have evanesced. It may be beneficial to screen for new RBC alloantibody development after transfusion before possible antibody evanescence. STUDY DESIGN AND METHODS: Our institution started a new initiative for episodically transfused patients with SCD to obtain at least one antibody screen 2-6 months after transfusion as part of their clinical care. A database was created to prospectively track all transfused patients for 1 year and their post-transfusion antibody screen results. Patients received prophylactically CEK-matched RBC units. RESULTS: During the study year, 138 patients with SCD received a total of 242 RBC transfusions. Patients with a history of an RBC alloantibody (n = 13, 9.4%) had previously received more RBC units than non alloimmunized patients (median 11 vs. 2 RBC units, p = .0002). A total of 337 post-transfusion antibody screens were obtained in 127 patients (92.0%) with 110 patients (79.7%) having at least one antibody screen 2-6 months post-transfusion. With this prospective testing, two new RBC alloantibodies (anti-C and -M) were identified in two patients. CONCLUSION: It is feasible to test for new RBC alloantibody development in most episodically transfused patients with SCD as part of their routine care. The yield of this screening appears low with CEK matching, but it could still provide important information for individual patients.

Transcranial Doppler Screening in a Current Cohort of Children With Sickle Cell Anemia: Results From the DISPLACE Study.

Stroke prevention guidelines for sickle cell anemia (SCA) recommend transcranial Doppler (TCD) screening to identify children at stroke risk; however, TCD screening implementation remains poor. This report describes results from Part 1 of the 28-site DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) study, a baseline assessment of TCD implementation rates. This report describes TCD implementation by consortium site characteristics; characteristics of TCDs completed; and TCD results based on age. The cohort included 5247 children with SCA, of whom 5116 were eligible for TCD implementation assessment for at least 1 study year. The majority of children were African American or Black, non-Hispanic and received Medicaid. Mean age at first recorded TCD was 5.9 and 10.5 years at study end. Observed TCD screening rates were unsatisfactory across geographic regions (mean 49.9%; range: 30.9% to 74.7%) independent of size, institution type, or previous stroke prevention trial participation. The abnormal TCD rate was 2.9%, with a median age of 6.3 years for first abnormal TCD result. Findings highlight real-world TCD screening practices and results from the largest SCA cohort to date. Data informed the part 3 implementation study for improving stroke screening and findings may inform clinical practice improvements.

The impact of pre-existing HLA and red blood cell antibodies on transfusion support and engraftment in sickle cell disease after nonmyeloablative hematopoietic stem cell transplantation from HLA-matched sibling donors: A prospective, single-center, observational study.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) is curative for patients with sickle cell disease (SCD). Prior to HSCT, patients with SCD commonly receive RBC transfusions with some becoming RBC or HLA alloimmunized. This alloimmunization may impact post-HSCT transfusion requirements and donor engraftment. METHODS: The study population included patients with SCD transplanted on a single-center nonmyeloablative, HLA-matched sibling HSCT trial at the National Heart, Lung, and Blood Institute (NHLBI) who had a pre-HSCT sample available for HLA class I antibody testing. We evaluated transfusion requirements and engraftment outcomes comparing patients with and without pre-existing HLA and RBC antibodies. FINDINGS: Of 36 patients studied, 10 (28%) had HLA class I antibodies and 11 (31%) had a history of RBC alloantibodies. Up to day +45 post-HSCT, patients with HLA antibodies received more platelet transfusions (median 2.5 vs 1, p = 0.042) and those with RBC alloantibodies received more RBC units (median 7 vs 4, p = 0.0059) compared to respective non-alloimmunized patients. HLA alloimmunization was not associated with neutrophil engraftment, donor chimerism, or graft rejection. However, RBC alloimmunization correlated with a decreased donor T cell chimerism at 1 year (median 24% vs 55%, p = 0.035). INTERPRETATION: Pre-existing HLA and RBC alloantibodies are clinically significant for patients undergoing HLA-matched nonmyeloablative HSCT. Testing for both HLA and RBC antibodies is important to help estimate transfusion needs peri­HSCT. The association of lower donor T cell chimerism and pre-existing RBC alloantibodies needs further investigation. FUNDING: NIH Clinical Center and NHLBI Intramural Research Program (Z99 CL999999, HL006007-11) and the Thrasher Research Fund.

Parents of Children with Sickle Cell Disease Are Interested in Preimplantation Genetic Testing.

OBJECTIVE: To evaluate awareness of and attitudes toward preimplantation genetic testing (PGT) for sickle cell disease (SCD) among parents of children with SCD. STUDY DESIGN: Parents of children with SCD were given an educational handbook on PGT before a routine SCD clinic visit. After their clinic visit, parents were asked to complete an anonymous survey. RESULTS: Of 83 patents approached, 67 (81%) completed the survey. Only 16 of the 67 parents (24%) were previously aware of PGT for SCD. After our clinic-based education, 65 of the 67 parents (97%) indicated that it was important or very important for parents of children with SCD to know about PGT. Among parents interested in having more children, 29 of 32 (91%) would personally consider using PGT if covered by insurance. CONCLUSIONS: Parents of children with SCD are generally not aware of PGT. When educated in clinic, parents viewed information on PGT as valuable. Pediatricians and other health care professionals should inform parents of children with SCD about this reproductive option.

Parvovirus B19 infection in sickle cell disease: An analysis from the Centers for Disease Control haemoglobinopathy blood surveillance project.

OBJECTIVE: In the multicentre Haemoglobinopathy Blood Surveillance Project, to evaluate the seroprevalence of parvovirus B19 and DNA viral load in sickle cell disease (SCD). BACKGROUND: Although the epidemiology of parvovirus B19 seropositivity in SCD has been well documented, there are few studies that have assessed possible persistent parvovirus DNAemia and associated risk factors including blood transfusion. METHODS: A qualitative analysis of parvovirus B19 serology using ELISA and quantitative parvovirus B19 DNA by RT-PCR was performed in patients with SCD. RESULTS: Of 322 patients, 113 (35%) were parvovirus IgG positive and 119 (37%) were IgM positive at enrolment. The prevalence of IgG positivity increased with age. 71/322 (22%) were parvovirus DNA positive at enrolment with a mean viral load of 15 227 ± 55 227 SD. (range 72-329 238 IU/mL). Patients who were positive for parvovirus B19 DNA received a significantly higher red blood cell transfusion volume in the prior year compared to patients who were negative (mean RBC volume = 8310 mL vs 5435 mL, respectively; P = .0073). Seventy-seven patients had follow-up testing approximately 1 year after enrolment and 11/28 (39%) patients had persistently positive IgM. CONCLUSION: Further studies are needed to better understand the natural history of parvovirus B19 infection in SCD especially in relation to RBC transfusion as a risk factor, as well as disease outcome and severity.

Characteristics and outcomes of osteomyelitis in children with sickle cell disease: A 10-year single-center experience.

BACKGROUND: Patients with sickle cell disease (SCD) are at increased risk for osteomyelitis (OM). Diagnosis of OM in SCD is challenging as the clinical presentation is similar to a vasoocclusive crisis (VOC) with no diagnostic gold standard. We report characteristics and outcomes of OM in SCD patients treated at our center over 10-year period. DESIGN/METHOD: We conducted a retrospective analysis of patients with SCD who were treated for OM at our center over a 10-year period (2006-2016). Cases were identified utilizing radiology data mining software. Radiology reports and medical charts of potential OM cases were reviewed. RESULTS: Twenty-eight children with SCD were treated for OM at our institution. Patients treated for OM were largely similar to patients treated for a VOC. However, patients treated for OM had significantly higher C-reactive protein (10 mg/dL vs 5.58 mg/dL, P = 0.03) and erythrocyte sedimentation rate (60 mm/h vs 47 mm/h, P = 0.02). Magnetic resonance imaging (MRI) findings were consistent with OM in 18 (64%) patients and indeterminate in the remaining. Based on clinical, laboratory, and radiological findings, the diagnosis of OM was considered confirmed in 3 patients, probable in 6 patients, and presumed in 19 patients. Nontyphoidal Salmonella was isolated from cultures in 9 (32%) patients, while no organism was identified in 19 (67%) patients. All patients were treated with antibiotics. Six patients (21%) required surgical interventions. CONCLUSIONS: OM continues to pose diagnostic challenges. Most patients are treated for OM without definitive confirmation. Nontyphoidal Salmonella was the only organism identified in our cohort.

Transcranial Doppler Screening Adherence among Children with Sickle Cell Anemia Seen in the Emergency Department.

OBJECTIVE: To evaluate adherence to annual transcranial Doppler ultrasound (TCD) screening to prevent stroke among patients with sickle cell anemia (SCA) seen in the emergency department (ED). STUDY DESIGN: This retrospective chart review included patients with SCA seen at a large pediatric ED over 64 weeks. Patients who did not need a TCD (age <2 or ≥16 years, on chronic transfusions, history of an inadequate TCD) or were not followed at the study institution were excluded. Patients who had received a TCD in the last 12 months (TCD adherent) were compared with patients who had not (TCD nonadherent). RESULTS: During the study period, 257 patients with SCA in need of an annual TCD were identified and 63 patients (25%) had not received an annual TCD, including 19 patients (7%) who had never had a TCD. All TCD adherent patients had a clinic visit in the last year compared with 75% of TCD nonadherent patients, P < .0001. The mean interval time since the last hematology clinic appointment from the ED encounter was greater for the TCD nonadherent group: 70 vs 270 days, P < .0001. Demographics including markers of socioeconomic status were not significantly different between the 2 groups. CONCLUSIONS: Patients with SCA who present to the ED and are nonadherent to TCD screening guidelines are less likely to have had a recent hematology clinic visit. Future interventions to improve screening for stroke in SCA should target this patient population seen in the ED but not clinic.

Human leukocyte antigen (HLA) class I antibodies and transfusion support in paediatric HLA-matched haematopoietic cell transplant for sickle cell disease.

The relevance of donor-specific human leukocyte antigen (HLA) antibodies in HLA-mismatched haematopoietic cell transplant (HCT) is known, but the importance of HLA antibodies in HLA-matched HCT is unclear. We hypothesized that HLA antibodies detected before HCT would cause platelet transfusion refractoriness during HCT and investigated this in a multi-centre study. Pre-HCT samples from 45 paediatric patients with sickle cell disease (SCD) undergoing HLA-matched HCT were tested for HLA class I antibodies. The number of platelet transfusions received before day +45 was compared between those with and without antibodies. Thirteen of 45 (29%) patients had a positive HLA class I antibody screen, and these patients received significantly more platelet transfusions than patients without antibodies (median 19 vs. 7·5, P = 0·028). This platelet transfusion association remained significant when controlling for conditioning regimen. Among alloimmunized patients, there was no association between the panel-reactive antibody and the number of platelet transfusions. Patients with HLA class I antibodies also had a higher incidence of acute graft-versus-host disease (GVHD): 6/13 (46%) vs. 3/32 (9%), P = 0·011. Pre-HCT HLA class I alloimmunization is associated with increased platelet transfusion support and acute GVHD in paediatric HLA-matched HCT for SCD. Further studies are needed to investigate the pathobiology of this association.