Kim Smith-Whitley

High prevalence of red blood cell alloimmunization in sickle cell disease despite transfusion from Rh-matched minority donors

Red blood cell (RBC) transfusion is a key treatment of patients with sickle cell disease (SCD) but remains complicated by RBC immunization. In the present study, we evaluated the effects of antigen matching for Rh D, C, and E, and K and transfusion from African American donors in 182 patients with SCD. Overall, 71 (58%) chronic and 9 (15%) episodically transfused patients were alloimmunized. Fifty-five (45%) chronic and 7 (12%) episodically transfused patients were Rh immunized. Of 146 antibodies identified, 91 were unexplained Rh antibodies, one-third of which were associated with laboratory evidence of delayed transfusion reactions. Fifty-six antibodies occurred in patients whose RBCs were phenotypically positive for the corresponding Rh antigen and 35 in patients whose RBCs lacked the antigen and were transfused with Rh-matched RBCs. High-resolution RH genotyping revealed variant alleles in 87% of individuals. These data describe the prevalence of Rh alloimmunization in patients with SCD transfused with phenotypic Rh-matched African American RBCs. Our results suggest that altered RH alleles in both the patients and in the donors contributed to Rh alloimmunization in this study. Whether RH genotyping of patients and minority donors will reduce Rh alloimmunization in SCD needs to be examined.

Definitions of the phenotypic manifestations of sickle cell disease

Sickle cell disease (SCD) is a pleiotropic genetic disorder of hemoglobin that has profound multiorgan effects. The low prevalence of SCD (∼100,000/US) has limited progress in clinical, basic, and translational research. Lack of a large, readily accessible population for clinical studies has contributed to the absence of standard definitions and diagnostic criteria for the numerous complications of SCD and inadequate understanding of SCD pathophysiology. In 2005, the Comprehensive Sickle Cell Centers initiated a project to establish consensus definitions of the most frequently occurring complications. A group of clinicians and scientists with extensive expertise in research and treatment of SCD gathered to identify and categorize the most common complications. From this group, a formal writing team was formed that further reviewed the literature, sought specialist input, and produced definitions in a standard format. This article provides an overview of the process and describes 12 body system categories and the most prevalent or severe complications within these categories. A detailed Appendix provides standardized definitions for all complications identified within each system. This report proposes use of these definitions for studies of SCD complications, so future studies can be comparably robust and treatment efficacy measured. Use of these definitions will support greater accuracy in genotype–phenotype studies, thereby achieving a better understanding of SCD pathophysiology. This should nevertheless be viewed as a dynamic rather than final document; phenotype descriptions should be reevaluated and revised periodically to provide the most current standard definitions as etiologic factors are better understood, and new diagnostic options are developed. Am. J. Hematol. 2010.

Health-related quality of life in children with sickle cell disease: A report from the Comprehensive Sickle Cell Centers Clinical Trial Consortium†

Pediatric health‐related quality of life (HRQOL) questionnaires have been validated in children with sickle cell disease (SCD), but small sample sizes in these studies have limited clinical comparisons. We used the baseline clinical data from the Collaborative Data (C‐Data) Project of the Comprehensive Sickle Cell Centers (CSCC) Clinical Trial Consortium to perform a detailed, descriptive study of HRQOL using the PedsQL™ version 4.0 generic core and fatigue scales.

Indications and complications of transfusions in sickle cell disease.

Red cell transfusion remains an important part of the management of acute and chronic complications in SCD. The ongoing and emerging uses of transfusions in SCD may have significant benefits; however, the potential complications of transfusions also deserve careful consideration. In this report we review current indications for transfusions, transfusion complications, modifications of transfusion practices to mitigate risk, and potential considerations to improve transfusion outcomes. Pediatr Blood Cancer 2012;59:358–364.

Transcranial Doppler ultrasonography in siblings with sickle cell disease

Summary. The risk of stroke in sickle cell disease (SCD) may be influenced by either genetic or environmental factors. Elevated blood flow velocity in the large cerebral arteries, detected by transcranial Doppler (TCD) ultrasonography, predicts an increased stroke risk in children with SCD. We undertook this study to investigate the possibility of a familial predisposition to elevated cerebral blood flow velocity, a surrogate marker for stroke risk. We analysed the results of TCD studies performed on 63 children from 29 families that had more than one child with SCD. We assessed the association of elevated cerebral blood flow velocity with sibling TCD results as well as age and haemoglobin level, which are factors known to affect cerebral blood flow velocity. Positive or negative TCD results were highly correlated between family members (ru2003=u20030·61). The presence of a sibling with a positive TCD result was significantly associated with an elevated cerebral blood flow velocity in other siblings with SCD (odds ratiou2003=u200350·7, 95% confidence interval 10·1–253·7, Pu2003<u20030·001). Furthermore, children who had a sibling with a positive TCD result had a significantly higher TCD velocity than children with SCD but without a sibling who were matched for age, sex, genotype and haemoglobin level. Our results are consistent with a familial predisposition to cerebral vasculopathy in SCD.

Reproductive issues in sickle cell disease

As medical advances improve survival, reduce disease-related morbidity, and improve quality of life, reproductive issues will take higher priority in the sickle cell disease (SCD) community. A wide variety of topics are addressed in this chapter, including fertility, gonadal failure, erectile dysfunction, and menstrual issues in SCD. Etiologies of impaired male fertility are multifactorial and include hypogonadism, erectile dysfunction, sperm abnormalities, and complications of medical therapies. Much less is known about the prevalence and etiology of infertility in women with SCD. Other reproductive issues in women included in this review are pain and the menstrual cycle, contraception, and preconception counseling. Finally, long-term therapies for SCD and their impact on fertility are presented. Transfusional iron overload and gonadal failure are addressed, followed by options for fertility preservation after stem cell transplantation. Focus is placed on hydroxyurea therapy given its benefits and increasing use in SCD. The impact of this agent on spermatogenesis, azoospermia, and the developing fetus is discussed.

Periodic Limb Movements and Disrupted Sleep in Children with Sickle Cell Disease

STUDY OBJECTIVESnTo describe the rate, distribution and correlates of periodic limb movements in sleep (PLMS) in children with sickle cell disease (SCD).nnnDESIGNnProspective, cross-sectional.nnnSETTINGnHospital-based sleep laboratory.nnnPARTICIPANTSnSixty-four children aged 2-18 years with SCD, hemoglobin SS-type who had an overnight polysomnogram and a parent-completed Pediatric Sleep Questionnaire. Mean age was 8.4 years (SD 4.8); 50% were male.nnnINTERVENTIONSnN/A.nnnMEASUREMENTS AND RESULTSnThe mean PLMS index was 3.7 (6.6) and ranged from 0 to 31.8, with 23.4% of the sample having PLMS ≥ 5/h. Sleep efficiency was decreased (P = 0.03), and the total arousal index (P = 0.003) and PLMS arousal index (P < 0.001) were increased in children with PLMS ≥ 5/h compared to those with PLMS < 5/h. PLMS were most frequent in NREM stage 2 sleep and during the fourth hour of sleep. Inter-movement interval duration peaked at 25-30 s. Growing pains worst in bed or restlessness of the legs, suggesting restless legs syndrome (RLS), were reported in 12.5% of the total sample and were more common in children with elevated PLMS. A PLMS score for identifying elevated PLMS in children, based on items from the Pediatric Sleep Questionnaire, did not significantly predict PLMS ≥ 5/h.nnnCONCLUSIONSnElevated PLMS are common in children with SCD and are associated with sleep disruption and symptoms of RLS. Future research into the time structure of PLMS, their causes and consequences, and development of a disease-specific sleep disorders screening questionnaire, is needed in children with SCD.

The effects of hydroxycarbamide and magnesium on haemoglobin SC disease: results of the multi-centre CHAMPS trial.

In a phase‐II multi‐centre double‐blinded trial, we evaluated haematological effects of oral hydroxycarbamide (HC) and magnesium (Mg) in patients with HbSC, aged 5–53u2003years old. Subjects were randomized to HCu2003+u2003placebo, Mgu2003+u2003placebo, HCu2003+u2003Mg, or placebou2003+u2003placebo. The primary endpoint was the proportion of hyperdense red blood cells after 8u2003weeks. Thirty‐six subjects were evaluable, but the study was terminated early because of slow enrollment. In the combined HC groups, mean cell volume and HbF were increased, but differences were not seen in hyperdense red cells or vaso‐occlusive events. Mg had no effects. Further investigation of hydroxycarbamide as monotherapy in HbSC disease is warranted.

Screening U.S. College Athletes for Their Sickle Cell Disease Carrier Status

There are many issues surrounding the screening of collegiate athletes for their sickle cell disease carrier status (or sickle cell trait), a genetic condition. This paper summarizes the establishment of expert advice given to the Secretarys Advisory Committee on Heritable Disorders in Newborns and Children (SACHDNC) on the issue. The SACHDNC has developed a report to advise the Secretary of the USDHHS about the 2010 rule of the National Collegiate Athletic Association (NCAA) requiring testing for sickle cell trait in all incoming Division I student athletes. The SACHDNC does not support the NCAAs rule to screen collegiate athletes for sickle cell trait.

Validation of the Sickle Cell Disease Pain Burden Interview–Youth

UNLABELLEDnThe purpose of this study was to develop and validate a brief, clinically relevant, multidimensional interview to assess pain burden among children and adolescents with sickle cell disease (SCD). The Sickle Cell Disease Pain Burden Interview-Youth (SCPBI-Y) was developed using a panel of experts, patients, and caregivers. Validation was undertaken with children and youth with SCD, ages 7 to 21xa0years (N = 129), recruited from 4 urban childrens hospitals. Participants were recruited from inpatient (n = 62) and outpatient (n = 67) settings. The SCPBI-Y demonstrated strong internal consistency reliability, cross-informant concordance (child-caregiver), and test-retest reliability (outpatient setting). Moderate construct validity was found with validated measures of functional ability, pain, and quality of life. The SCPBI-Y demonstrated construct validity using a contrasted group approach between youth in inpatient versus outpatient settings and by severity of SCD symptoms, suggesting that youth in inpatient settings and with higher disease severity exhibited greater pain burden. Discriminant validity was found between SCPBI-Y and mood. Our preliminary findings suggest that the SCPBI-Y is a valid and reliable multidimensional interview that can be used in different clinical settings to evaluate pain burden among children and adolescents with SCD.nnnPERSPECTIVEnMultifaceted pain assessments are salient in providing optimal care to children and adolescents with SCD; however, current evaluations are lengthy and cumbersome to administer clinically. The current study introduces and validates a brief, clinically useful multidimensional interview to evaluate pain burden specific to youth with SCD.