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Background Hydroxyurea (HU) is highly effective treatment for Sickle Cell Disease (SCD). While pediatric use of HU is accepted clinical practice, barriers to use may impede its potential benefit.

Patients with severe immune thrombocytopenic purpura (ITP) may require an acute increase in the platelet count for surgery or ongoing hemorrhage as well as long-term maintenance treatment. Certain of these patients may be refractory to steroids, intravenous anti-D, intravenous immunoglobulin (IVIG), and splenectomy. Therefore, acute platelet increases were studied in 35 patients completely unresponsive to IVIG or high-dose steroid treatment. Because of their lack of response to either or both single agents, these patients were administered a 3- or 4-drug combination including IVIG 1 g/kg, intravenous methylprednisolone 30 mg/kg, Vinca alkaloids (VCR 0.03 mg/kg), and/or intravenous anti-D (50-75 μg/kg). Subsequent maintenance therapy with the oral combination of danazol (10-15 mg/kg) and azathioprine (2 mg/kg) was given to 18 of the 35 patients. Seventy-one percent of the patients responded to the intravenous combination treatment with acute platelet increases of at least 20×109/L to a level greater than 30×109/L. Two thirds of the patients given maintenance therapy achieved stable platelet counts greater than 50×109/L without other treatments. One patient developed an ileus, but otherwise there was little toxicity of combination treatment. Combination chemotherapy is a useful approach for patients with ITP refractory to conventional treatments both for acute induction and for long-term maintenance therapy.

1. M. Catherine Driscoll, MD* 1. *Director, Hematology Program, Children's Hospital at Montefiore, Bronx, NY After completing this article, readers should be able to: 1. Describe the pathogenesis of sickle cell disease. 2. Delineate the complications of sickle cell disease and their management. 3. Review guidelines for health maintenance and preventive measures. 4. Discuss the current treatments for sickle cell disease. Sickle cell disease (SCD) is a chronic hemolytic anemia that includes the hemoglobin (Hb) variants SS, SC, S-beta thalassemia, SO Arab, SD, and other rare S-Hb genotypes. SCD is one of the most common genetic diseases worldwide. Sickle disorders are seen commonly in sub-Saharan Africa but also occur in the Mediterranean, India, and the Arabian Peninsula. The geographic distribution of sickle hemoglobinopathies corresponds to the distribution of malaria; indeed, the sickle gene in the heterozygote (AS) form protects against death from endemic Plasmodium falciparum malaria infection. In addition, the clinical manifestations of SCD vary among these geographic sites, with individuals from India, the Arabian Peninsula, and Senegal having milder disease than those from parts of Africa. This pattern suggests that genetic modifiers ameliorate the disease in certain populations and contribute to the significant variation in clinical manifestations. The presence of SCD in North, South, and Central America is due to immigration patterns and represents primarily the more severe African types. The genetic defect producing sickle Hb is a single nucleotide substitution (GTG for GAG) at codon 6 of the beta globin gene on chromosome 11 that results in the substitution of valine for glutamic acid. This hydrophobic amino acid substitution allows Hb S to polymerize on deoxygenation, and multiple polymers bundle to form rodlike structures that distort the red cell into the classic crescent shape. Sickled red cells are less deformable in the microcirculation and provoke a cascade of events that results in vascular occlusion, organ ischemia, and eventually, chronic end-organ damage. The ancillary events of polymerization that …

Hydroxyurea (HU) improves hematologic parameters and decreases adverse events in patients with sickle cell disease (SCD). HU has been proposed as an alternative to chronic transfusions for secondary stroke prevention. Transcranial doppler (TCD) is an accepted method of stroke risk stratification in patients with SCD. We sought to determine if HU affects TCD velocities in children with SCD.A cohort of 24 children with HbSS with a baseline TCDi prior to HU and a follow-up after at least 6 months of therapy was analyzed. Twenty-four age-matched children with HbSS formed the control group. Differences in hematologic parameters before and after HU therapy were evaluated.TCDi velocities decreased in the HU-treated patients. The adjusted mean change in TCDi velocities was -13.0 cm/sec (95% CI -20.19, -5.92) in the HU-treated group and +4.72 cm/sec (95% CI -3.24, 12.69) in the controls. Changes in TCDi between the two groups were statistically significant (P0.001). Changes in hematologic parameters were not predictive of changes in TCDi velocities in the treated patients. Four out of five patients with TCDi velocities170 cm/sec had normalization of TCDi velocities on HU. Mean change was -34.75 cm/sec in this subgroup. No patients experienced cerebrovascular accidents (CVA) while on HU.HU-treated patients experienced statistically significant decreases in TCDi velocities compared to age-matched controls. Changes in hematologic parameters were not predictive of changes in TCDi velocities in the treated group. The decrease in TCDi velocities is not a consequence of changes in hematologic values in patients treated with HU.

Cerebrovascular disease is a common cause of morbidity in sickle cell anemia (HbSS): approximately 10% of patients have a clinical stroke before 20 years of age, and another 22% have silent infarction on magnetic resonance imaging. The phenotypic variation among patients with HbSS suggests a role for modifier genes and/or environmental influences. To assess the familial component of clinical stroke in HbSS, we estimated the prevalence of clinical stroke among all patients and among HbSS sibling pairs at 9 pediatric centers. The sample included 3425 patients with sickle cell disease who were younger than 21 years, including 2353 patients with HbSS. The stroke prevalence was 4.9% for all genotypes; 7.1% for patients with HbSS; 1.1% for patients with HbSbeta(o) thalassemia; 0.6% for patients with Sbeta(+) thalassemia; and 0% for patients with HbSC. In 207 sibships, more than 1 child had HbSS. There were 42 sibships in which at least 1 sibling had a stroke, and in 10 of the 42, 2 siblings had a stroke. A permutation test indicated that the number of families in which 2 children had strokes was larger than the number expected if strokes were randomly distributed among children in sibships (P =.0012). There was no difference in stroke prevalence based on sex, nor was the mean age at stroke presentation significantly different between singletons and sibships with stroke. We conclude that there is a familial predisposition to stroke in HbSS. Attempts to identify genetic modifiers should be initiated with family-based studies.

Stroke is one of the most devastating complications of patients with sickle cell disease (SCD). Currently, there are no known molecular or genetic markers that can be used to assess the risk of stroke in this population. We have previously shown that relative hypertension may be one risk factor for stroke in SCD. In a case-control study, we investigated the association between GT-repeat polymorphism within the angiotensinogen (AGT) gene and the risk of stroke in pediatric patients with SCD. After informed consent was obtained, 63 patients (21 stroke subjects and 42 nonstroke control subjects matched according to age and sex) with SCD followed at local pediatric hematology clinics were genotyped to test the association of specific GT-repeat alleles of the AGT gene and occurrence of stroke. There were statistical differences in the distribution of the genotypes among stroke and nonstroke SCD patients (chi(2) = 10.82, df = 11, P < 0.05). We also found GT-repeat alleles A3 and/or A4 of the AGT gene conferred a four-fold increase in the risk of stroke (odds ratio [OR] = 4, P < 0.05). The attributable odds ratio for allele A3 and A4 is 2.24 and 4.33, respectively (P < 0.005). Our results suggest that GT-repeat within the AGT gene may be associated with risk of stroke in pediatric SCD. The relative risk of stroke in the presence of alleles A3 and/or A4 is fourfold greater than in the absence of these alleles. If these data are substantiated in a larger cohort of patients, our results indicate that the determination of GT-repeat of AGT gene may be a useful genetic marker to assess the risk for stroke of patients with SCD. Am. J. Hematol. 68:164-169, 2001. Published 2001 Wiley-Liss, Inc.

The carbohydrate-deficient glycoprotein syndromes are a group of recently described autosomal recessive, metabolic defects affecting multiple systems. The disorder is caused by inefficient posttranslational glycosylation of glycoproteins. Patients with the syndrome present early in life with psychomotor retardation, seizures, hypotonia, and stroke-like episodes. They also have dysmorphic features including almond-shaped eyes, constant squint, inverted nipples, and buttock fat pads. One of the features of the syndrome is coagulopathy, and we report here a patient who presented with a prolonged activated partial thromboplastin time, and was subsequently diagnosed with the carbohydrate-deficient glycoprotein syndrome. We also summarize the results of five previously published studies of the coagulation system in these patients. Most of the reported patients are deficient in factor XI, protein C, antithrombin III, and protein S. Other coagulation proteins are less frequently affected. Both bleeding and thrombosis have been observed, yet the cause of the stroke-like episodes remains speculative. The carbohydrate-deficient glycoprotein syndrome is an increasingly recognized multisystem disorder affecting hemostasis, and thus will involve clinical hematologists as part of a multidisciplinary team caring for patients with the syndrome. Am. J. Hematol. 60:66–69, 1999. © 1999 Wiley-Liss, Inc.

anemia. Blood 2010;115:5300–5311. 10. Thornburg CD, Calatroni A, Telen M, Kemper AR. Adherence to hydroxyurea therapy in children with sickle cell anemia. J Pediatr 2010;156:415–419. 11. Sichle Cell Disease Guidelines-Hydroxyurea Chapter. http://rover.nhlbi.nih. gov/guidelines/scd/about.htm. Accessed November 21, 2011. 12. de Montalembert M, Brousse V, Elie C, et al. Long-term hydroxyurea treatment in children with sickle cell disease: Tolerance and clinical outcomes. Haematologica 2006;91:125–128. 13. Zimmerman SA, Schultz WH, Davis JS, et al. Sustained long-term hematologic efficacy of hydroxyurea at maximum tolerated dose in children with sickle cell disease. Blood 2004;103:2039–2045. 14. Burgess SW SP, Morawska A, Devadason SG. Assessing adherence and factors associated with adherence in young children with asthma. Respirology 2008;13:559–563. 15. Jentzsch NS, Camargos PA, Colosimo EA, Bousquet J. Monitoring adherence to beclomethasone in asthmatic children and adolescents through four different methods. Allergy 2009;64:1458–1462. 16. Thornburg CD, Calatroni A, Telen M, Kemper AR. Adherence to hydroxyurea therapy in children with sickle cell anemia. J Pediatr 2010;156:415– 419. 17. Osterberg L, Blaschke T. Adherence to medication. N Engl J Med 2005;353: 487–497. 18. Franklin VL, Waller A, Pagliari C, Greene SA. A randomized controlled trial of Sweet Talk, a text-messaging system to support young people with diabetes. Diabet Med 2006;23:1332–1338. 19. Lee SJ, Joffe S, Kim HT, et al. Physicians’ attitudes about quality-of-life issues in hematopoietic stem cell transplantation. Blood 2004;104:2194– 2200. 20. Wong EC, Perez-Albuerne E, Moscow JA, Luban NL. Transfusion management strategies: A survey of practicing pediatric hematology/oncology specialists. Pediatr Blood Cancer 2005;44:119–127. 21. Streiff MB, Smith B, Spivak JL. The diagnosis and management of polycythemia vera in the era since the Polycythemia Vera Study Group: A survey of American Society of Hematology members’ practice patterns. Blood 2002;99: 1144–1149.

The molecular mechanisms governing γ-globin expression in a subset of fetal hemoglobin (α2γ2: HbF) expressing red blood cells (F-cells) and the mechanisms underlying the variability of response to hydroxyurea induced γ-globin expression in the treatment of sickle cell disease are not completely understood. Here we analyzed intra-person clonal populations of basophilic erythroblasts (baso-Es) derived from bone marrow common myeloid progenitors in serum free cultures and report the level of fetal hemoglobin production in F-cells negatively correlates with expression of BCL11A, KLF1 and TAL1. We then examined the effects of hydroxyurea on these three transcription factors and conclude that a successful induction of γ-globin includes a reduction in BCL11A, KLF1 and TAL1 expression. These data suggests that expression changes in this transcription factor network modulate γ-globin expression in F-cells during steady state erythropoiesis and after induction with hydroxyurea.

Transcranial Doppler (TCD) is an effective method for screening patients with sickle cell disease (SCD) at risk for first stroke. Its usefulness in monitoring children with SCD receiving transfusions has not been established. The authors studied 17 children with SCD evaluated with TCDs and magnetic resonance angiograms (MRAs) while receiving transfusion therapy. Patients with normalized TCDs had normal MRAs that remained normal on transfusions. Patients with persistently abnormal TCDs had abnormal MRAs. In these children, TCD velocities decreased but rarely reverted to normal. Patients with low TCD velocities (

Abstract 4621 Renal failure is one of the major complications of sickle cell disease (SCD), affecting 5-18% of the patients. Microalbuminuria (MA), which has a prevalence of 26.5% in all children with SCD, is used as a marker of preclinical glomerular damage and renal disease progression. However, measuring MA alone may miss renal damage involving tubular proteins. We hypothesize that sickle cell nephropathy subjects will have increased urinary excretion of Transforming Growth Factor Beta-1 (TGF β1) and Neutrophil Gelatinase–Associated Lipocalin (NGAL) as compared to age-matched controls (CTR). We also hypothesize that urinary excretion of these proteins will be associated with severity of anemia in SCD. Enzyme-Linked Immunosorbent Assay (ELISA) kits were used to detect urinary excretion of TGF β1/NGAL, and corrected to urine creatinine. Mean age, gender, and race were not statistically different among the groups. Urinary excretion of TGF β1 was significantly higher in SCD subjects (26.4 pg/mg Cr +/-1.5) vs. CTR (14.9 pg/mg Cr +/-2.4), (p Our data suggests that urinary TGF β1 may serve as a urinary biomarker to monitor the progression of renal disease in SCD. This assumption needs to be tested prospectively. Disclosures: No relevant conflicts of interest to declare.

Hydroxyurea therapy is associated with reduced morbidity among patients with sickle cell disease (SCD). Avascular necrosis of the femoral head (AVN) is one potentially debilitating complication of SCD. In this study, we examined the relationship between hydroxyurea use and the prevalence of AVN among children with SCD. We performed a retrospective chart review of 202 children with SCD, aged 10–21 years, followed in the pediatric hematology program at the Children’s Hospital at Montefiore (Bronx, NY) between July 2007 and 2008. Abstracted data included age, ethnicity, SCD genotype, frequency of hospitalization, hip radiograph results, laboratory data and hydroxyurea use. Hip radiographs were performed prospectively as part of SCD health maintenance from 2005–2008. Forty-four patients were excluded because they did not have a screening hip radiograph. Descriptive statistics were calculated for independent variables. T-tests and chi-square tests were used to compare clinical and demographic characteristics of children with and without AVN. Multivariate logistic regressions were used to estimate the odds ratio of having AVN among SCD patients. Our final sample consisted of 158 patients whose demographic characteristics are listed in Table 1. The prevalence of AVN was 16.5% (n=26). Of the clinical variables analyzed, we identified significant associations between the presence of AVN and hydroxyurea use (p=.005), as well as older age (p=.013) (Table 1.) Children with AVN had significantly lower mean lactic dehydrogenase levels (LDH) (p=.04) and higher mean corpuscular volumes (MCV) (p=.012). (Table 2.) After controlling for gender, ethnicity, sickle cell genotype, and frequency of hospitalizations, age was also found to be associated with AVN (OR 1.15, 95% confidence interval (CI): 1.01,1.31, p=0.033). SCD patients on hydroxyurea had higher odds of having AVN compared to non-users (OR 3.51, 95% CI: 1.31, 9.38, p= 0.013). Laboratory values (MCV, Hemoglobin, LDH and Hematocrit) had a high degree of collinearity and were removed from the final model. In summary, the prevalence of AVN in our sample was 16.5%. This is substantially higher than the prevalence of approximately 6% reported by the Cooperative Study of Sickle Cell Disease for comparative age groups in a prospective study1. SCD patients exposed to hydroxyurea were three times more likely to have AVN than those not exposed to this drug. Vaso-occlusive pain crisis is a recognized risk factor for AVN, thus we could expect a higher rate of AVN among patients on hydroxyurea. However, the odds ratio of 3.5 is unexpectedly high and warrants further investigation into the role of hydroxyurea as a risk factor for AVN. Nonetheless, these preliminary results suggest that more stringent screening regimens for AVN may be indicated among this subset of patients. Table 1. Clinical characteristics of patients with and without avn *p5 8 (6%) 2 (8%) Table 2. Mean Laboratory Values for Patients With And Without AVN No AVN AVN *p

Cerebrovascular disease is a common complication in sickle cell anemia (SCA) with overt stroke occuring in 10% of patients and silent stroke in 24% of patients by age 20 years. Etiologies of overt stroke in SCA are heterogenous and include stenosis of large arteries, hemorrhage, hypertensive and hypoxic encephalopathy. Candidate genes identified as possible modifiers of overt stroke in SCA include adenylate cyclase 9 (ADCY9, rs731471 intron C/T), endothelin-converting enzyme (ECE-1, rs212527, intron A/G), Klotho (KL, rs480780, intron C/A), plasminogen activator inhibitor-1 (PAI-1, rs1799768, − 675 4/5,), transforming growth factor beta receptor 3 (TGFBR3, rs284157, intron G/A), tumor necrosis factor alpha (TNF, rs1800629,-308 G/A), and interlukin 4 receptor (IL4R, rs1805015, 503S/P). We examined the association of these candidate genes in a cohort of patients with SCA and stenosis of large cerebral vessels who are followed at a single institution. Patients with stenosis (n = 42, male = 22) were identified as having overt stroke (n = 29) or positive transcranial Doppler (TCD) (n = 13). The mean age at time of stroke or (+) TCD was 7.8 years. All had large vessel stenosis on magnetic resonance angiogram imaging (MRA). A control group of patients with SCA and normal TCD were identified (n = 71, males = 46, mean age = 14.8 years).This control group has passed through the peak years of stroke risk, ages 2–10 years. Single nucleotide polymorphisms (SNPs) were genotypic using novel Taqman assays. Genotypic associations were determined using logistic regression analysis with odds ratios (OR), 95% confidence intervals, and p-values reported. Among the candidate genes only ADYC9 (OR = 2.75, CI 1.2–6.3, p = 0.017) and TGFBR3 (OR = 2.33, CI 1.0–5.3, p = 0.043) had significant association with stenosis of large vessels in SCA. ADYC9 is a membrane-associated enzyme that catalyzes cAMP formation, which is critical for neuronal signaling and survival. TGFBR3 has a role in cardiac endothelial cell transformation to mesenchyme. Genotypic studies of a complex trait such as stroke in SCA will eventually lead to early diagnosis and new or early interventions. However, such genetic studies require clear definitions of phenotypic subtypes based on neuroimaging studies, including MRA.

Cerebrovascular disease (CVD) of both large and small cerebral vessels occurs in one-third of patients with sickle cell anemia (SCA) by age 20 years. Large vessel stenosis (LVS) occurs in ~10% of patients and is associated with overt stroke and/or (+) transcranial Doppler (TCD). Epistatic genetic modifiers are postulated to account for the significant phenotypic heterogeneity of SCA and likely contribute to CVD. Potential genetic modifers of CVD may be found in pathways for inflammation, adhesion, stress/immune reactions, angiogenesis, thrombosis, and oxidant generation. Peripheral blood monocytes are activated in SCA and contribute to inflammation and endothelial activation. The goal of this study is to determine if there is a difference in gene expression profiles of monocytes in patients with SCA and LVS, compared to SCA controls without CVD, and to normal African American (AA) controls. The study group consisted of 1) SCA patients with LVS [n = 6, (moyamoya = 3, no moyamoya =3)], 2) SCA patients without CVD and nornal TCD (n = 3), and 3) normal AA controls (n = 3). The 6 SCA-LVS patients were on chronic transfusion programs to maintain Hb S