AnemoCheck-LRS: An optimized, color-based point-of-care test to identify severe anemia in limited-resource settings

BACKGROUND: Severe anemia is common and frequently fatal for hospitalized patients in limited-resource settings. Lack of access to low-cost, accurate, and rapid diagnosis of anemia impedes the delivery of life-saving care and appropriate use of the limited blood supply. The WHO Haemoglobin Colour Scale (HCS) is a simple low-cost test but frequently inaccurate. AnemoCheck-LRS (limited-resource settings) is a rapid, inexpensive, color-based point-of-care (POC) test optimized to diagnose severe anemia. METHODS: Deidentified whole blood samples were diluted with plasma to create variable hemoglobin (Hb) concentrations, with most in the severe (≤ 7 g/dL) or profound (≤ 5 g/dL) anemia range. Each sample was tested with AnemoCheck-LRS and WHO HCS independently by three readers and compared to Hb measured by an electronic POC test (HemoCue 201 RESULTS: For 570 evaluations within the limits of detection of AnemoCheck-LRS (Hb ≤ 8 g/dL), the average difference between AnemoCheck-LRS and measured Hb was 0.5 ± 0.4 g/dL. In contrast, the WHO HCS overestimated Hb with an absolute difference of 4.9 ± 1.3 g/dL for samples within its detection range (Hb 4-14 g/dL, n = 405). AnemoCheck-LRS was much more sensitive (92%) for the diagnosis of profound anemia than WHO HCS (22%). CONCLUSIONS: AnemoCheck-LRS is a rapid, inexpensive, and accurate POC test for anemia. AnemoCheck-LRS is more accurate than WHO HCS for detection of low Hb levels, severe anemia that may require blood transfusion. AnemoCheck-LRS should be tested prospectively in limited-resource settings where severe anemia is common, to determine its utility as a screening tool to identify patients who may require transfusion

Burden of sickle cell trait and disease in the Uganda Sickle Surveillance Study (US3): a cross-sectional study

Background Sickle cell disease contributes substantially to mortality in children younger than 5 years in sub-Saharan Africa. In Uganda, 20 000 babies per year are thought to be born with sickle cell disease, but accurate data are not available. We did the cross-sectional Uganda Sickle Surveillance Study to assess the burden of disease. Methods The primary objective of the study was to calculate prevalence of sickle cell trait and disease. We obtained punch samples from dried blood spots routinely collected from HIV-exposed infants in ten regions and 112 districts across Uganda for the national Early Infant Diagnosis programme. Haemoglobin electrophoresis by isoelectric focusing was done on all samples to identify those from babies with sickle trait or disease. Findings Between February, 2014, and March, 2015, 99 243 dried blood spots were analysed and results were available for 97 631. The overall number of children with sickle cell trait was 12 979 (13·3%) and with disease was 716 (0·7%). Sickle cell numbers ranged from 631 (4·6%) for trait and 23 (0·2%) for disease of 13 649 in the South Western region to 1306 (19·8%) for trait and 96 (1·5%) for disease of 6581 in the East Central region. Sickle cell trait was seen in all districts. The lowest prevalence was less than 3·0% in two districts. Eight districts had prevalence greater than 20·0%, with the highest being 23·9%. Sickle cell disease was less common in children older than 12 months or who were HIV positive, which is consistent with comorbidity and early mortality. Interpretation Prevalence of sickle cell trait and disease were high in Uganda, with notable variation between regions and districts. The data will help to inform national strategies for sickle cell disease, including neonatal screening

Hemoglobin variants identified in the Uganda Sickle Surveillance Study

The Uganda Sickle Surveillance Study analyzed dried blood spots that were collected from almost 100 000 infants and young children from all 10 regions and 112 districts in the Republic of Uganda, with the primary objective of determining the prevalence of sickle cell trait and disease. An overall prevalence of 13.3% sickle cell trait and 0.7% sickle cell disease was recently reported. The isoelectric focusing electrophoresis technique coincidentally revealed numerous hemoglobin (Hb) variants (defined as an electrophoresis band that was not Hb A, Hb F, Hb S, or Hb C) with an overall country-wide prevalence of 0.5%, but with considerable geographic variability, being highest in the northwest regions and districts. To elucidate these Hb variants, the original isoelectric focusing (IEF) gels were reviewed to identify and locate the variant samples; corresponding dried blood spots were retrieved for further testing. Subsequent DNA-based investigation of 5 predominant isoelectric focusing patterns identified 2 α-globin variants (Hb Stanleyville II, Asn78Lys; Hb G-Pest, Asp74Asn), 1 β-globin variant (Hb O-Arab, Glu121Lys), and 2 fusion globin variants (Hb P-Nilotic, β31-δ50; Hb Kenya, Aγ81Leu-β86Ala). Compound heterozygotes containing an Hb variant plus Hb S were also identified, including both Hb S/O-Arab and HbS/Kenya. Regional differences in the types and prevalence of these hemoglobin variants likely reflect tribal ancestries and migration patterns. Algorithms are proposed to characterize these Hb variants, which will be helpful for emerging neonatal hemoglobinopathy screening programs that are under way in sub-Saharan Africa

Building a sickle cell disease screening program in the Republic of Uganda: the Uganda Sickle Surveillance Study (US3) with 3 years of follow-up screening results.

The prevalence of sickle cell disease (SCD) in the Republic of Uganda is higher than in the United States, but there are no accurate countrywide data and no newborn screening program has been established. The Early Infant Diagnosis (EID) program is well established to analyze dried blood spots (DBSs) collected from HIV-exposed infants (ie, those born to HIV-positive mothers). HIV-positive infants are identified and placed into specialty care. At the request of the Uganda Ministry of Health, a partnership was developed between Cincinnati Children’s Hospital Medical Center, Makerere University, and the Uganda Central Public Health Laboratories (CHPL) to build local laboratory capacity for testing DBSs for sickle cell trait (SCT) and SCD. The Uganda Sickle Surveillance Study (US3) was designed to identify SCT or SCD in DBSs collected throughout the national EID program. After US3, screening commenced in high-burden districts with local capacity built to provide clinical care for affected infants

Prevalence of inherited blood disorders and associations with malaria and anemia in Malawian children

In sub-Saharan Africa, inherited causes of anemia are common, but data are limited regarding the geographical prevalence and coinheritance of these conditions and their overall contributions to childhood anemia. To address these questions in Malawi, we performed a secondary analysis of the 2015-2016 Malawi Micronutrient Survey, a nationally and regionally representative survey that estimated the prevalence of micronutrient deficiencies and evaluated both inherited and noninherited determinants of anemia. Children age 6 to 59 months were sampled from 105 clusters within the 2015-2016 Malawi Demographic Health Survey. Hemoglobin, ferritin, retinol binding protein, malaria, and inflammatory biomarkers were measured from venous blood. Molecular studies were performed using dried blood spots to determine the presence of sickle cell disease or trait, α-thalassemia trait, and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Of 1279 eligible children, 1071 were included in the final analysis. Anemia, iron deficiency, and malaria were common, affecting 30.9%, 21.5%, and 27.8% of the participating children, respectively. α-Thalassemia trait was common (>40% of children demonstrating deletion of 1 [33.1%] or 2 [10.0%] α-globin genes) and associated with higher prevalence of anemia (P < .001). Approximately 20% of males had G6PD deficiency, which was associated with a 1.0 g/dL protection in hemoglobin decline during malaria infection (P = .02). These data document that inherited blood disorders are common and likely play an important role in the prevalence of anemia and malaria in Malawian children

Epigenetic and molecular profiles of erythroid cells after hydroxyurea treatment in sickle cell anemia

Hydroxyurea has been shown to be efficacious for the treatment of sickle cell anemia (SCA), primarily through the induction of fetal hemoglobin (HbF). However, the exact mechanisms by which hydroxyurea can induce HbF remain incompletely defined, although direct transcriptional effects and altered cell cycle kinetics have been proposed. In this study, we investigated potential epigenetic and alternative molecular mechanisms of hydroxyurea- mediated HbF induction by examining methylation patterns within the Gγ -globin promoter and miRNA expression within primary CD71+ erythrocytes of patients with SCA, both at baseline before beginning hydroxyurea therapy and after reaching maximum tolerated dose (MTD). Using both cross-sectional analysis and paired-sample analysis, we found that the highly methylated Gγ-globin promoter was inversely correlated to baseline HbF levels, but only slightly altered by hydroxyurea treatment. Conversely, expression of several specific miRNAs was significantly increased after hydroxyurea treatment, and expression of miR-26b and miR-151-3p were both associated with HbF levels at MTD. The significant associations identified in these studies suggest that methylation may be important for regulation of baseline HbF, but not after hydroxyurea treatment, whereas changes in miRNAexpression may be associated with hydroxyurea-mediated HbF induction. This study was registered at ClinicalTrials. gov (NCT00305175). © 2011 by The American Society of Hematology

Assessment of genotoxicity associated with hydroxyurea therapy in children with sickle cell anemia

Hydroxyurea induces fetal hemoglobin, improves laboratory parameters, and ameliorates clinical complications of sickle cell anemia (SCA), but its long-term efficacy and safety in this patient population remain incompletely defined. Although generally considered non-DNA reactive, an important safety concern is that hydroxyurea may indirectly cause genotoxic damage. To better address this safety issue of hydroxyurea in patients with SCA, we measured the production of micronuclei (MN) in red blood cells (RBCs) as a marker of genotoxicity.Blood samples were collected from children with SCA enrolled in the Hydroxyurea Study of Long-term Effects (ClinicalTrials.gov NCT00305175). Flow cytometry quantified circulating MN-containing erythrocyte sub-populations before and during hydroxyurea exposure. The frequency of micronucleated reticulocytes (MN-CD71 +) and micronucleated mature erythrocytes (MN-RBC) was then tested for associations with laboratory and clinical data. In cross-sectional analysis of 293 blood samples from 105 children with SCA and a median of 2 years of hydroxyurea therapy, exposure to hydroxyurea was associated with significantly increased frequencies of MN-CD71 + and MN-RBC compared to baseline. The increases were evident by 3 months of therapy, and did not escalate further with up to 12 years of continuous drug exposure. In prospective longitudinal analysis, substantial inter-individual variation in the effect of hydroxyurea on %MN-CD71 + was observed that was associated with the expected laboratory effects of hydroxyurea.In conclusion, clinically relevant exposure to hydroxyurea is associated with increased MN production consistent with erythroblast genotoxicity but with substantial inter-patient variability. Associations between increased %MN-CD71 + and laboratory benefits suggest that hydroxyurea effects on MN production may be related to individual patient sensitivity to hydroxyurea within the bone marrow. © 2010 Elsevier B.V