The Effect of Health Care Disparities on Complications and Mortality in Sickle Cell Disease

Abstract Introduction: Sickle cell disease (SCD) is a chronic and debilitating disorder that affects approximately 100,000 Americans and results in the development of significant complications, leading to high numbers of hospitalizations, healthcare cost and mortality. Despite the advent of newer therapies, the overall rate of complications has continued to rise. We aimed to study the prevalence of complications in SCD as well as its relation to differing insurance status. Methods: Patients with SCD were identified using ICD-9 codes 2826, 28260, 28261, 28262, 28263, 28264, 28268 and 28269 from the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample from 1999 to 2014. Admission with acute chest syndrome, acute myocardial infarction (AMI), avascular necrosis of the hip (AVN), end stage renal disease (ESRD), pneumococcal infections, splenic sequestration and stroke. Univariate and bivariate analyses were performed using the Chi square test. Cox proportional hazard regression was used to control for multiple confounders in calculating the hazard ratios of an event occurrence and mortality. Results: A total of 216,438 (Weighted=1,066,536) observations were identified from the years 1999 to 2014. The median age for male patients was 25 years and that for females was 27. Observing the trends from 1999 to 2014, the prevalence of acute chest syndrome increased from 1.22% to 8.82% (p=0.002), splenic sequestration from to 0.08 % to 1% (p=0.01) and AVN from 1 % to 8.8% (p=0.001). The prevalence of stroke and ESRD were unchanged over the interval studied. After controlling for confounding factors such as race, age, sex, income, comorbidities and insurance status, the hazard ratio of mortality for various complications is significantly elevated. Also, after controlling for multiple confounders, the patient's insurance status plays a significant role in the risk of developing a complication and subsequent mortality (Table 1). Discussion: The data indicates that the rate of complications from SCD have risen since 1999. With newer therapies and better understanding, the life expectancy of SCD patients has risen over time, nearly doubling from 1951 to 2018. The increased frequency of complications may be attributed to better survivorship and a rising number of older SCDs patients. However, our data also suggests that insurance status plays a significant role in the complication rate of SCD. The uninsured and patients with Medicaid have significantly increased risk of developing disease complications and resultant mortality. This could be the result of reduced access to care and health disparities due to race, socioeconomic status and insurance status. Disclosures No relevant conflicts of interest to declare.

Download Full-text

A case of severe multi-system disease in a sickle cell SC patient caused by parvovirus B19 infection

Journal of Clinical Images and Medical Case Reports ◽

10.52768/2766-7820/1314 ◽

2021 ◽

Vol 2 (5) ◽

Author(s):

Mohamed Almuqamam ◽

◽

Swetha Madhavarapu ◽

Nataly Apollonsky ◽

◽

...

Keyword(s):

Sickle Cell Disease ◽

Sickle Cell ◽

Parvovirus B19 ◽

Acute Infection ◽

Organ Injury ◽

Acute Chest Syndrome ◽

Cell Disease ◽

Splenic Sequestration ◽

Increased Risk ◽

Parvovirus B19 Infection

Sickle Cell Disease (SCD) is an inherited hemoglobinopathy, which results in production of abnormal hemoglobin S. HbSC disease is a variant of SCD, which shares a similar clinical complication profile to HbSS disease, but often thought to be a milder condition. In patients with SCD, Hb S in deoxygenated state undergoes polymerization, leading to hemolysis, vaso-occlusive events, and eventually end-organ damage. Among other complications in patients with SCD is increased risk of complications caused by parvovirus B19. We present a case of a 14-year-old female with HbSC disease who presented to the emergency room with complaint of abdominal pain and found to have splenic sequestration. Splenic sequestration progressed rapidly, Hemoglobin (hb) dropped to 4.6 g/dl and acute chest syndrome (ACS) developed. She was treated following the ACS protocol, received 4 units of Packed Red Blood Cells (PRBC) and subsequently underwent a single volume PRBC exchange transfusion. Considering her unusual presentation, with severe ARDS from alveolar hemorrhage requiring mechanical ventilation and multi-organ injury, several autoimmune and infectious conditions with a cytokine storm component including COVID-19 disease, were considered. Results of viral testing revealed parvovirus B19 IgM antibodies signifying an acute infection. She fully recovered with supportive care and was discharged home. Multisystem involvement simulating connective tissue disorders or malignancies with acute parvovirus B19 infection has been reported and is considered extremely rare. To our knowledge, there were no reports of pediatric patients with SC disease presenting with splenic sequestration and ACS in the setting of parvovirus B19 multisystem disease. Keywords: sickle cell disease; acute respiratory distress syndrome; acute chest syndrome; parvovirus B19.

Download Full-text

Polymorphisms in TNFα Are Associated with Cerebrovascular Events in Sickle Cell Disease.

Blood ◽

10.1182/blood.v114.22.1540.1540 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1540-1540 ◽

Cited By ~ 1

Author(s):

Latorya A Barber ◽

Allison E Ashley-Koch ◽

Melanie E. Garrett ◽

Karen L Soldano ◽

Marilyn J. Telen

Keyword(s):

Sickle Cell Disease ◽

Sickle Cell ◽

Conflicts Of Interest ◽

Umbilical Vein ◽

Acute Chest Syndrome ◽

Cell Disease ◽

Data Set ◽

Clinical Complications ◽

Cerebrovascular Events ◽

Increased Risk

Abstract Abstract 1540 Poster Board I-563 Tumor necrosis factor alpha (TNFα) is a pro-inflammatory cytokine that stimulates phagocytosis, neutrophil recruitment, and expression of adhesion molecule VCAM-1. Plasma levels of TNFα have been found to be increased in sickle cell disease (SCD), and in vitro studies show that TNFα causes increased adherence of sickle red blood cells to human umbilical vein endothelial cells. A polymorphism in the promoter region of the TNFα gene has previously been associated with stroke in children with SCD (Hoppe et al., 2007). The current study was designed to identify associations of additional TNFα single nucleotide polymorphisms (SNPs) with SCD clinical complications. We analyzed five SNPs in the TNFα gene in 509 DNA samples of SCD patients from Duke University, University of North Carolina at Chapel Hill, and Emory University. In our data set, cerebrovascular events (CVEs), including overt stroke, seizures, and transient ischemic attacks, occurred in 133 out of 509 SCD patients (26.1%). SNP genotyping was performed using Taqman genotyping assays from Applied Biosystems. Due to low minor allele frequencies (<0.05) for all the SNPs examined, genetic associations with SCD clinical complications were examined by using allele tests. After controlling for age, gender, and use of hydroxyurea, two of the five TNFα SNPs, rs2228088 and rs3093665, were significantly associated with CVEs (p=0.013 and 0.029, respectively). The odds that SCD patients with a G allele at rs2228088 suffered from CVEs were 0.485 times that for patients with the T allele, suggesting that the G allele had a protective effect. The odds of having the A allele at rs3093665 and suffering from CVEs was also reduced, at 0.45 compared to the C allele. Neither SNP was found to be in linkage disequilibrium (LD) with any of the other SNPs analyzed (r2≤0.002). There was also strong association of SNP rs2228088 with acute chest syndrome (ACS; p=0.003), occurring in 382 out of 509 SCD patients (75%). However, in this analysis, the G allele was associated with increased risk for ACS (OR=2.313). In addition to the association with CVEs, the SNP rs3093665 was also significantly associated with priapism (p=0.03), reported by 86 of 223 male SCD patients (38.6%). In this analysis, the A allele was protective, as had been observed for CVE (OR=0.188). Additionally, we found no difference in steady state plasma TNFα levels between genotypes for the two SNPs. The functional significance of these SNPs is presently unknown. SNP rs2228088 is a synonymous SNP located in the coding region, and rs3093665 is located in the 3' untranslated region of the TNFα gene. While the G to T change at SNP rs2228088 does not translate to a change in amino acid sequence, the A to C change at SNP rs3093665 may affect mRNA stability due to its location. It is also possible that one or both of these SNPs is in LD with another functionally relevant SNP. Our findings thus support previous data implicating TNFα polymorphisms in risk for central nervous system events. Interestingly, ACS has been previously associated with seizures, stroke and altered mental status in adults and children with SCD (Vinchinsky et al., 2000) and with silent cerebral infarcts and reversible posterior leukoencephalopathy syndrome in children with SCD (Henderson et al., 2003). However, in our dataset, ACS and the occurrence of CVEs were not associated (p=0.24). Further studies are required to elucidate these and other factors that potentially correlate with SCD clinical complications. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Outcome of Initiating Hydroxyurea in Infancy for Patients with Sickle Cell Disease 2011-2018

Blood ◽

10.1182/blood-2018-99-114174 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4816-4816

Author(s):

Ronay Thomas ◽

Robin Yates Dulman ◽

Angela Lewis ◽

Bailey Notarangelo ◽

Elizabeth Yang

Keyword(s):

Sickle Cell Disease ◽

Sickle Cell ◽

Conflicts Of Interest ◽

Fetal Hemoglobin ◽

Acute Chest Syndrome ◽

Cell Disease ◽

Splenic Sequestration ◽

Ed Visits ◽

Us Children ◽

Prospective Longitudinal

Abstract Introduction Approximately 2000 babies are born with sickle cell disease annually in the US. Children with severe forms of sickle cell disease (SCD), such as Hemoglobin SS and Hemoglobin S beta 0 thalassemia (Sbeta0), are at risk for severe anemia, vasoocclusive pain crisis, acute chest syndrome, splenic sequestration, central nervous system ischemia, and shortened life expectancy. The drug Hydroxyurea (HU) increases Hgb F, is effective in ameliorating many sickle cell symptoms, and improves survival. Safety and efficacy of HU in children and infants have been demonstrated. Methods Following publication of the BABY HUG trial results in 2011, the Comprehensive Pediatric Sickle Cell Program of Northern Virginia implemented HU initiation for all infants with Hgb SS or Hgb Sbeta0. HU was prescribed at age 6-7 months for 2 patients and at 9-12 months of age for 22 patients. HU dosage was diligently adjusted at clinic visits to maximize Hgb F. An IRB-approved prospective, longitudinal database was launched to follow each patient's clinical course and outcome in 6-month increments. Data are reported for children born after January 2011 who were started on HU by 12 months of age, followed on HU therapy continuously in this clinic, and were at least 2 years of age by June 2018. Results All 24 children in the analysis have Hgb SS. Sixteen children have been followed for 3 years or more, 11 children have been followed for 4 years or more, 7 children have been followed for 5 years or more, 4 children have been followed for 6 years or more, and 3 children have been followed for 7 years. Average Hgb at 6 months of age was 9.5 g/dL, and ranged between 9.5 and 10.7 g/dL for age 1-7. Average Hgb F was 34.1% at 6 months of age and dipped to 29.1% at 1 year of age, but was maintained above 30% from age 1.5 - 3 years and at 27.8% - 30.5% for age 3.5 - 7 years. For a total of 92 person-years, there were 27 hospitalizations, all within the first 3 years of life. 20/27 (74%) hospitalizations were for fever, pneumonia without hypoxia or need for transfusion, or other infections, 5/27 (19%) were for splenic sequestration, and only 1/27 (4%) hospitalization was for pain that occurred before HU initiation. ED visits totaled 68, 53/68 (78%) were for fever and 47/68 (69%) occurred in the first 3 years of life. Only 2/68 (3%) ED visits were attributed to dactylitis/pain, occurring prior to HU initiation. ED visits after age 3 were all for fevers. The most common complication specific to sickle cell disease was splenic sequestration, which is not preventable by HU. All 4 transfusions given were for splenic sequestration. Conclusion Continuous tracking in a single center observational study demonstrated that continuous HU therapy starting in infancy maintained Hgb and Hgb F at or above pre-HU levels into childhood, is associated with no hospitalizations after age 3 and no ED visits for pain after HU initiation by age 1. No acute chest syndrome requiring oxygen or transfusion, no abnormal or conditional TCD, and no overt strokes occurred in this cohort. Implementation of HU for children with sickle cell disease starting in infancy is feasible in the community and is effective in maintaining high fetal hemoglobin and preventing disease complications. Table. Table. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Case Report: Acute Stroke in Young Adult Patient with Moyamoya Syndrome Secondary to Sickle Cell Disease

Blood ◽

10.1182/blood-2020-134202 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 13-13

Author(s):

Oladipo Cole ◽

Asia Filatov ◽

Javed Khanni ◽

Patricio Espinosa

Keyword(s):

Case Report ◽

Sickle Cell Disease ◽

Sickle Cell ◽

Moyamoya Disease ◽

Conflicts Of Interest ◽

Acute Chest Syndrome ◽

African American Female ◽

Moyamoya Syndrome ◽

Cell Disease ◽

Radiographic Findings

Moyamoya disease, well described in literature, is a chronic cerebrovascular occlusive disorder. It is characterized by progressive stenosis/occlusion of the terminal portions of the internal carotid arteries (ICA) and the proximal portions of the middle cerebral arteries (MCA). Less frequently described is Moyamoya syndrome, the name given to radiographic findings consistent with Moyamoya disease, but with an identifiable cause. The diseases associated with Moyamoya Syndrome include Sickle Cell Disease (SCD), Thalassemias, and Down's Syndrome to name a few. Common complications of Moyamoya include both ischemic and hemorrhagic strokes. Upon literature review, Moyamoya syndrome caused by SCD is not well described. When it is, the discussion is centered around the pediatric patient population and surgical management. Our case report describes a 22-year-old African American female with SCD who initially presented with Acute Chest Syndrome. Her hospital course was complicated by development of overt debilitating neurologic deficits. Subsequently, she was found to have Moyamoya Syndrome on neuroimaging. She was successfully treated with medical management without any surgical intervention. This case highlights the necessity of thorough examination, differential diagnosis, imaging findings, and consideration of predisposing syndromes in the work-up for Moyamoya syndrome; especially individuals with Sickle Cell Disease. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Utility of Procalcitonin in Differentiating Acute Chest Syndrome from Vaso-Occlusive Crisis in Sickle Cell Disease

Blood ◽

10.1182/blood-2020-143454 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 10-11

Author(s):

Satish Maharaj ◽

Simone Chang ◽

Karan Seegobin ◽

Marwan Shaikh ◽

Kamila I. Cisak

Keyword(s):

Sickle Cell Disease ◽

Sickle Cell ◽

Complete Blood Count ◽

Conflicts Of Interest ◽

Statistical Significance ◽

Acute Chest Syndrome ◽

Adult Males ◽

Cell Disease ◽

Unequal Variances ◽

Recorded Data

Background: Acute chest syndrome (ACS) frequently complicates sickle cell disease (SCD) and is a leading cause of hospitalization and mortality. Many factors have been implicated in ACS, including infections, thrombosis, fat and pulmonary emboli. However, a clear etiology is not defined in 50% of the cases and ACS is considered a clinical endpoint for different pathogenic processes (Vichinsky et al 2000). The non-specific nature of ACS makes diagnostic tests challenging, and there are no serum tests clinical used to aid diagnosis. Procalcitonin (PCT) is a prohormone of calcitonin and serum PCT rises within hours of an inflammatory stimulus. PCT has clinical utility as a marker of severe systemic inflammation, infection, and sepsis (Becker et al. 2008). Few studies have evaluated PCT as a biomarker for ACS in patients presenting with vaso-occlusive crises (VOC). Two studies have reported no difference in PCT (Biemond et al. 2018 and Stankovic et al 2011), while one study reported higher PCT between ACS and VOC (Patel et al 2014). Methods: We retrospectively reviewed 106 patients with SCD who presented to the emergency department with fever and painful crises during 2015-2019. The patients were divided into two categories based on discharge diagnoses - patients with VOC only (n=88) and patients with ACS (n=18). Inclusion criteria for both groups were patients with SCD, 17 years and older and PCT measurement on presentation. Exclusion criteria were defined as patients who had received empiric antibiotics prior to PCT testing. Data collected on presentation included genotype, age, gender, complete blood count, PCT, creatinine, total bilirubin and hydroxyurea use. Length of stay was recorded. Data was analyzed between the two groups using descriptive statistics and accounting for unequal variances, withp-value set at 0.05 for significance. Results: Demographics and clinical characteristics are summarized in Table 1 (Figure). The sample included primarily adult males (77%), with about two-thirds on hydroxyurea. Genotype HbSS (73.6%) was most prevalent followed by HbSC (22.6%) and HbSβ (3.8%). The ACS group had a higher percentage of HbSS, lower use of hydroxyurea and higher mean bilirubin. Mean PCT for the ACS group was 0.52 ng/mL (range, 0.05-2.04), compared to 0.31 ng/mL (range, 0.02-6.82) in the VOC group; withp=0.084. ROC analysis showed a PCT>0.5ng/mL had 39% sensitivity and 85% specificity for ACS in this sample. Conclusion: In this sample, PCT on presentation was higher in those with ACS compared to VOC, but this difference did not achieve statistical significance. Further study in a larger population would be useful to evaluate this finding. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Identification of Clinical and Laboratory Parameters Associated with the Development of Acute Chest Syndrome during Vaso-Occlusive Episodes in Children with Sickle Cell Disease: A Preliminary Step before Assessing Specific and Early Treatment Strategies

Journal of Clinical Medicine ◽

10.3390/jcm8111839 ◽

2019 ◽

Vol 8 (11) ◽

pp. 1839

Author(s):

Madhi ◽

Kamdem ◽

Jung ◽

Carlier-Gonod ◽

Biscardi ◽

...

Keyword(s):

Sickle Cell Disease ◽

Pain Score ◽

Sickle Cell ◽

Multivariate Model ◽

Red Blood Cell Transfusion ◽

Predictive Score ◽

Acute Chest Syndrome ◽

Cell Disease ◽

Laboratory Parameters ◽

Increased Risk

This prospective observational study sought to ascertain clinical and laboratory parameters associated with the development of acute chest syndrome (ACS) during vaso-occlusive episodes (VOE) in children with sickle cell disease (SCD). It was performed at the pediatric department of the university Intercommunal Créteil hospital. All children with SCD (all sickle genotypes) consecutively admitted from November 2013 to December 2016 for painful VOEs and no evidence of ACS were included. Clinical and laboratory parameters collected at admission and within 48 h after admission were compared for children in whom ACS developed or not. Variables that were statistically significant on univariate analysis or considered to be clinically relevant were included in a multivariable model to ascertain the risk factors associated with the development of ACS during a VOE. The variables retained in the multivariate model were used to construct a predictive score for ACS. For each included child and during the study period, only data from the first VOE and/or the first ACS were analyzed. Among 191 hospitalizations for painful VOEs, for 176 children with SCD, ACS developed in 35 during hospitalization. Mean hospital stay was longer for children with ACS versus VOEs alone (7.6 (±2.3) vs. 3.3 (±1.8) days, p < 0.0001), and all children with ACS versus 28/156 (17.9%) with VOEs alone received red blood cell transfusion (p < 0.0001). The multivariate model retained pain score (≥9/10), pain localization (abdominal or spinal pain or involving more than two limbs), and high reticulocyte (≥260 × 109/L) and neutrophil (>10 × 109/L) counts, at admission, as independently associated with ACS development. The area under the receiver operating characteristic curve for the ACS predictive score was 0.82 (95% CI: 0.74–0.89), and the negative predictive value was 97.7%. The evolution profiles during the first 48 h differed between children with ACS and VOEs alone, with a more rapid decline of pain score and leucocytosis in children with VOEs. Clinical and laboratory measurements at admission may be simple parameters to identify children with increased risk of ACS development during VOEs and to facilitate early diagnosis of this respiratory complication. Also, the persistent elevation of leukocyte count on day 2 may be considered a sign of evolving ACS.

Download Full-text

Clinical events in the first decade in a cohort of infants with sickle cell disease. Cooperative Study of Sickle Cell Disease [see comments]

Blood ◽

10.1182/blood.v86.2.776.bloodjournal862776 ◽

1995 ◽

Vol 86 (2) ◽

pp. 776-783 ◽

Cited By ~ 321

Author(s):

FM Gill ◽

LA Sleeper ◽

SJ Weiner ◽

AK Brown ◽

R Bellevue ◽

...

Keyword(s):

Sickle Cell Disease ◽

Sickle Cell ◽

Clinical Course ◽

The United States ◽

Beta Thalassemia ◽

Acute Chest Syndrome ◽

Cooperative Study ◽

Cell Disease ◽

Splenic Sequestration ◽

Clinical Events

Within the Cooperative Study of Sickle Cell Disease, 694 infants with confirmed sickle cell disease were enrolled at less than 6 months of age. Information about the nature and frequency of complications was collected prospectively over a 10-year period. Painful crises and acute chest syndrome were the most common sickle cell-related events in homozygous sickle cell anemia (SS), hemoglobin SC disease (SC), and S beta thalassemia patients (overall incidence in SS patients of 32.4 and 24.5 cases per 100 person-years, respectively). Bacteremia occurred most frequently in SS children under 4 years of age and in SC patients less than 2 years of age. The mortality rate was low in this cohort compared with that found in previous reports. Twenty children, all with Hb SS, died (1.1 deaths per 100 person-years among SS patients). Infection, most commonly with Streptococcus pneumoniae and Hemophilus influenzae, caused 11 deaths. Two children died of splenic sequestration, 1 of cerebrovascular accident, and 6 of unclear causes. Two patients underwent cholecystectomies, and 17 underwent splenectomies after one or more splenic sequestration crises. The experience of this cohort should reflect closely the true clinical course of those children with Hb SS and Hb SC disease who are observed in sickle cell centers in the United States.

Download Full-text

Alloantibody Formation In Sickle Cell Disease

Blood ◽

10.1182/blood.v122.21.2395.2395 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2395-2395 ◽

Cited By ~ 1

Author(s):

Joep Sins ◽

Saurabh Zalpuri ◽

Marjon Cnossen ◽

Anita W. Rijneveld ◽

Jean-Louis Kerkhoffs ◽

...

Keyword(s):

Sickle Cell Disease ◽

General Population ◽

Sickle Cell ◽

Cumulative Incidence ◽

Cox Regression ◽

Conflicts Of Interest ◽

Cumulative Number ◽

Cell Disease ◽

Cox Regression Analysis ◽

Increased Risk

Abstract Background Transfusion of red blood cells (RBC) is a common intervention to treat and prevent complications in sickle cell disease (SCD). However, frequent transfusions may lead to erythrocyte alloimmunization, thereby complicating donor matching procedures and posing patients at risk for hemolytic transfusion reactions. Little information is available about the risk of alloimmunization of sickle cell patients living in European countries. In the Netherlands extensive matching procedures to prevent alloimmunization were introduced a decade ago, but the effect on alloimmunization has not been evaluated yet. Aims The primary aim of this study is to evaluate the cumulative incidence of first alloantibody formation in a Dutch cohort of transfused SCD patients, and to compare this with a general Dutch RBC-transfused population. In addition, the effect of extended RBC matching protocols on the incidence of alloantibody formation in SCD and potential clinical determinants of alloimmunization will be assessed. Methods We conducted a retrospective cohort study and collected data on SCD patients (genotypes HbSS, HbSC, HbSβ0 and HbSβ+ thalassemia), diagnosed in three Dutch Sickle Cell Treatment Centers that received non-extended matched (ABO, RhD) RBC transfusions between 1984-2004 and extended matched (at least ABO, Rhesus phenotype, Kell) RBC transfusions between 2004-2011. In addition, we compared this population with a general population of 3 042 patients that received non-extended matched (ABO, RhD) RBC transfusions between 2005-2009 in the Leiden University Medical Center (Zalpuri et al. 2012). Cohorts were not matched for ethnicity. Alloimmunization risk was calculated as Kaplan-Meier incidence with cumulative number of transfusions as time variable. The association with the clinical determinants gender, SCD-phenotype and ethnicity was analyzed with Cox-regression analysis. Results A total of 291 SCD patients received 7 957 RBC units. Alloantibody formation occurred in 52 (17.9%) patients. The cumulative incidence of alloimmunization was 9% after 5 RBC units, 15% after 10, 24% after 20 and 34% after 40 RBC units. Multivariate analysis, correcting for the cumulative number of transfusions, demonstrated a significantly increased risk of alloantibody formation in our SCD cohort when compared to a general population of transfused patients (HR 7.5 (95% CI: 5.06-11.14), where the cumulative incidence of alloimmunization was 1.1% after 5, 2.4% after 10, 3.4% after 20 and 6.5% after 40 RBC units. No association could be demonstrated between alloantibody formation and clinical determinants such as gender, SCD-phenotype or ethnicity. However, a significant reduction in alloimmunization was observed in SCD patients that received their first transfusion from the year 2004 onwards, after preventive matching for Rhesus phenotype and Kell was introduced for SCD patients (HR 0.48 (95% CI: 0.24-0.97)). Conclusion The overall rate of first RBC alloantibody formation in our cohort was 17.9% and the risk of alloimmunization increased substantially with an increasing number of RBC transfusions. A unique comparison with a general cohort of Dutch transfused patients demonstrates a significantly higher risk of alloantibody formation in SCD, acknowledging earlier findings. This may partially be explained by differences in RBC antigens between patients of African descent and the predominantly Caucasian donors. Besides the number of RBC units, no other clinical risk factors for allo-immunization in SCD could be identified. The effectiveness of extended RBC matching protocols in the prevention of alloimmunization for chronically transfused patients in the participating centers was confirmed. Disclosures: No relevant conflicts of interest to declare.

Download Full-text

Microparticles As Biomarkers Of Osteonecrosis Of The Hip In Sickle Cell Disease

Blood ◽

10.1182/blood.v122.21.2226.2226 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2226-2226

Author(s):

Anne M Marsh ◽

Raymond Schiffelers ◽

Ginny Gildengorin ◽

Frans A Kuypers ◽

Carolyn Hoppe

Keyword(s):

Sickle Cell Disease ◽

Sickle Cell ◽

Conflicts Of Interest ◽

Vascular Occlusion ◽

Predictive Biomarker ◽

Acute Chest Syndrome ◽

Mobility Limitations ◽

Cell Disease ◽

The Past ◽

D Dimer

Abstract Introduction Sickle cell disease (SCD) is the most common cause of osteonecrosis of the femoral head (ONFH) in children. ONFH is a debilitating condition that is associated with mobility limitations, chronic pain, and an impaired quality of life. While the mechanisms that cause ONFH remain unknown, ischemia from recurrent microvascular occlusion is likely to play a role. Vascular occlusion may result directly from obstruction by sickled cells, or indirectly via complex interdependent pathways characterized by sustained endothelial activation, chronic inflammation, and coagulation. Microparticles (MP) are small, cell membrane-derived vesicles generated in response to cellular activation, injury or apoptosis. MPs have emerged as potential modulators of inflammation and thrombosis and have been found to be elevated in patients with ONFH in the general population. Objective This pilot study examined whether microparticle levels in patients with SCD who have ONFH differ from SCD patients without ONFH, as well as healthy African American (AA) controls. Methods Subjects were recruited at their baseline status and were excluded if they had been transfused within the past 30 days, hospitalized for a vaso-occlusive pain episode, acute chest syndrome, fever or surgery within the past 30 days, or had bony lesions of the femur or hip due to causes unrelated to SCD. For MP analysis, whole blood was collected in sodium citrate tubes and centrifuged for 15 minutes at 1500 x g at 20° C to generate platelet poor plasma. Aliquots of the plasma were immediately frozen and stored at -80° C until the time of MP analysis. 300 μl samples were diluted in PBS and centrifuged at 10000 x g for 1hr and the supernatant was centrifuged at 100,000 x g for 2 hr. The pellet was re-suspended in 1 mL of PBS and subjected to nanoparticle-tracking analysis to determine concentration and size. Additional laboratory biomarkers of inflammation and coagulation, including highly-sensitive C-reactive protein (hs-CRP), von Willebrand factor antigen (vWF Ag), tissue factor (TF), and D-dimer were analyzed for differences between groups. Analysis of variance was used to compare MP and biomarker levels between the three groups. The institutional review board at Children's Hospital & Research Center Oakland approved the study protocol and written informed consent was obtained from all participants. Results Characteristics of the 30 subjects enrolled are shown in Table I. Total microparticle levels in ONFH(+) patients were 2.3-fold higher than in ONFH(-) patients, and 2.5-fold higher than in AA controls (Figure 1). Mean MP levels for ONFH(+) patients, ONFH(-) patients, and AA controls were 4.55 x 1010, 1.99 x 1010, and 1.85 x 1010, respectively. Microparticle levels in ONFH(-) SCD patients did not differ from AA controls. There were no statistically significant differences in hsCRP, vWF Ag, TF, or D-dimer levels between the ONFH(-) and ONFH(+) groups. Conclusions The results of this study demonstrate significantly elevated MP levels in individuals with SCD who have ONFH. Additional studies are needed to better understand the mechanistic effects of MPs on the development of ONFH and to determine whether MP levels may be useful as a predictive biomarker for early disease detection. This publication was supported by NIH/NCRR UCSF-CTSI Grant Number UL1 RR024131. Disclosures: No relevant conflicts of interest to declare.

Download Full-text

The Cerebral Vasculopathy In Malian Sickle Cell Anemia Children: Lesson From Routine Transcranial Doppler Screening

Blood ◽

10.1182/blood.v122.21.4687.4687 ◽

2013 ◽

Vol 122 (21) ◽

pp. 4687-4687

Author(s):

Dapa Aly Diallo ◽

Aldiouma Guindo ◽

Alain Dorie ◽

Boubacari Ali Touré ◽

Baba Fané ◽

...

Keyword(s):

Sickle Cell Disease ◽

Sickle Cell ◽

Transcranial Doppler ◽

Conflicts Of Interest ◽

Fetal Hemoglobin ◽

Preventive Treatment ◽

Cell Disease ◽

Control Center ◽

Increased Risk ◽

Patients At Risk

Cerebral vasculopathy is one of the major complications of Sickle Cell Disease (SCD). 11% of the homozygous SCD patients experience stroke by age of 20 years. The use of Transcranial Doppler (TCD) allows identification of patients at risk for stroke and leads to implementation of a preventive treatment that contributes to limit the burden of SCD particularly during childhood. Using TCD screening, we evaluated the prevalence and incidence of cerebral vasculopathy in Malian SCD children. During the years 2008 to 2013, 572 children, 249 girls and 323 boys, age range (2-17yrs) were routinely screened by TCD at our Sickle Cell Disease Research and Control Center of Bamako, Mali. The overall prevalence of cerebral vasculpathy defined by conditional (1.5-1.79 cm/sec) and abnormal TCD (≥ 1.80 cm/sec) in this population is 17.1%. The highest proportion (92.9%) was observed in homozygous SCD patients while the percentage of affected patients was much lower in S/β0thalassemia (4.1%) and in SC (3.1%) patients. No cases were observed in S/β+thalassemia patients. SCD children <9 years old were more susceptible to cerebral vasculopathy complications than those above this age threshold (P<0.001). Low hemoglobin levels and low fetal hemoglobin were associated with an increased risk of cerebral vasculopathy. During the study, 4 of 444 children with normal TCD converted to conditional TCD, while 5 of 68 children with conditional TCD converted to abnormal TCD. This conversion from conditional to abnormal TCD was associated with a mean decrease in Hb value of 0.37g/dL (P=0.002). In conclusion this study shows high prevalence and incidence of cerebral vasculopathy in Malian SCD children. While chronic transfusion programs significantly reduces the risk of stroke in SCD patients with abnormal TCD, at present there are no well articulated strategies to prevent conversion from conditional to abnormal TCD. A more comprehensive approach would hopefully reduce the morbidity and mortality due to cerebral vasculopathy in SCD affected children. Disclosures: No relevant conflicts of interest to declare.

Download Full-text