Reducing transfusion utilization for children with sickle cell anemia in sub-Saharan Africa with hydroxyurea: Analysis from the phase I/II REACH trial

Children with sickle cell anemia (SCA) in Africa frequently require transfusions for SCA complications. Despite limited blood supplies, strategies to reduce their transfusion needs have not been widely evaluated or implemented. We analyzed transfusion utilization in children with SCA before and during hydroxyurea treatment. REACH (Realizing Effectiveness Across Continents with Hydroxyurea, NCT01966731) is a longitudinal Phase I/II trial of hydroxyurea in children with SCA from Angola, Democratic Republic of Congo, Kenya, and Uganda. After enrollment, children had a two-month pre-treatment screening period followed by 6 months of fixed-dose hydroxyurea (15-20 mg/kg/day), 18 months of dose escalation, and then stable dosing at maximum tolerated dose (MTD). Characteristics associated with transfusions were analyzed with univariate and multivariable models. Transfusion incidence rate ratios (IRR) across treatment periods were calculated. Among 635 enrolled children with 4124 person-years of observation, 258 participants (40.4%) received 545 transfusions. The transfusion rate per 100 person-years was 43.2 before hydroxyurea, 21.7 on fixed-dose, 14.5 during dose escalation, and 10.8 on MTD. During MTD, transfusion incidence was reduced by 75% compared to pre-treatment (IRR 0.25, 95% confidence interval [CI] 0.18-0.35, p < .0001), and by 50% compared to fixed dose (IRR 0.50, 95% CI 0.39-0.63, p < .0001). Hydroxyurea at MTD decreases transfusion utilization in African children with SCA. If widely implemented, universal testing and hydroxyurea treatment at MTD could potentially prevent 21% of all pediatric transfusions administered in sub-Saharan Africa. Increasing hydroxyurea access for SCA should decrease the transfusion burden and increase the overall blood supply.

Estimating the number of probable new SARS-CoV-2 infections among tested subjects from the number of confirmed cases

OBJECTIVES

In most African countries, confirmed COVID-19 case counts underestimate the number of new SARS-CoV-2 infection cases. We propose a multiplying factor to approximate the number of biologically probable new infections from the number of confirmed cases.

METHODS

Each of the first thousand suspect (or alert) cases recorded in South Kivu (DRC) between 29 March and 29 November 2020 underwent a RT-PCR test and an IgM and IgG serology. A latent class model and a Bayesian inference method were used to estimate (i) the incidence proportion of SARS-CoV-2 infection using RT-PCR and IgM test results, (ii) the prevalence using RT-PCR, IgM and IgG test results; and, (iii) the multiplying factor (ratio of the incidence proportion on the proportion of confirmed -RT-PCR+- cases).

RESULTS

Among 933 alert cases with complete data, 218 (23%) were RT-PCR+; 434 (47%) IgM+; 464 (~ 50%) RT-PCR+, IgM+, or both; and 647 (69%) either IgG + or IgM+. The incidence proportion of SARS-CoV-2 infection was estimated at 58% (95% credibility interval: 51.8-64), its prevalence at 72.83% (65.68-77.89), and the multiplying factor at 2.42 (1.95-3.01).

CONCLUSIONS

In monitoring the pandemic dynamics, the number of biologically probable cases is also useful. The multiplying factor helps approximating it.

Co-occurrence of oculocutaneous albinism type 2 and mild sickle cell disease explained by HbS/βthal genotype in an individual from the Democratic Republic of Congo

Oculocutaneous albinism type 2 (OCA2) is a pigmentation disorder characterized by hypopigmentation of the skin, hair and eyes and ocular features. Sickle cell disease (SCD) is caused either by homozygosity of the beta globin gene variant c.20A > T/p.Glu6Val giving rise to severe anemia or by combined abnormal hemoglobins (HbS/βthal) leading to mild SCD. We report a 45 years old female patient from the Democratic Republic of Congo affected with these two disorders. She presented with creamy white skin and numerous pigmented patches called dendritic freckles, nystagmus, foveal hypoplasia grade 2, photophobia and very poor visual acuity. Sequencing of the OCA2 gene identified the common exon 7 deletion and a new pathogenic variant c.1444A > C/p.Thr482Pro. She had mild SCD with a total Hb level of 101 g/l. Hbβ sequencing identified variants c.20A > T giving rise to HbS and c.315 + 1 G > A characteristic of β-thalassemia. A heterozygous 3.7 kb deletion of the α globin gene was also found. The combined Hbβ/α globin genotype explains the mild SCD phenotype. Co-occurrence of OCA2 and SCD raises the question whether the patient's phenotype simply results from the addition of the two diseases' phenotypes or whether interaction between the two diseases modulates the phenotype of each other.

[Realities for a Sickle Cell Disease Control Strategy in the World Health Organization African Region]

The Network for the Study of Sickle Cell Disease in Central Africa or REDAC, is a network of African, European and American researchers whose aim is to combat sickle cell disease. Its congresses take place every year in the partner countries with international symposia alternating with workshops. REDAC enables host countries to obtain from local authorities a real involvement in the fight through resolutions in line with national strategies of fight. The Seventh International Symposium of REDAC was held in 2018 in Antananarivo, Madagascar under the auspices of the Malagasy Minister of Health and the Malagasy Senate Authorities. The theme chosen was that of strategies to combat sickle cell disease recommended by the WHO. The presentations focused on neonatal screening, early diagnosis, management of sickle cell disease and new therapies (marrow transplant, gene therapy and treatment with hydroxyurea).

Genetic diversity of human head lice and molecular detection of associated bacterial pathogens in Democratic Republic of Congo

BACKGROUND

Head louse, Pediculus humanus capitis, is an obligatory blood-sucking ectoparasite, distributed worldwide. Phylogenetically, it occurs in five divergent mitochondrial clades (A-E); each exhibiting a particular geographical distribution. Recent studies suggest that, as in the case of body louse, head louse could be a disease vector. We aimed to study the genetic diversity of head lice collected in the Democratic Republic of the Congo (DR Congo) and to screen for louse-borne pathogens in these lice.

METHODS

A total of 181 head lice were collected from 27 individuals at the Monkole Hospital Center located in Kinshasa. All head lice were genotyped and screened for the presence of louse-borne bacteria using molecular methods. We searched for Bartonella quintana, Borrelia recurrentis, Rickettsia prowazekii, Anaplasma spp., Yersinia pestis, Coxiella burnetii and Acinetobacter spp.

RESULTS

Among these head lice, 67.4% (122/181) belonged to clade A and 24.3% (44/181) belonged to clade D. Additionally, for the first time in this area, we found clade E in 8.3% (15/181) of tested lice, from two infested individuals. Dual infestation with clades A and D was observed for 44.4% individuals. Thirty-three of the 181 head lice were infected only by different bacterial species of the genus Acinetobacter. Overall, 16 out of 27 individuals were infested (59.3%). Six Acinetobacter species were detected including Acinetobacter baumannii (8.3%), Acinetobacter johnsonii (1.7%), Acinetobacter soli (1.7%), Acinetobacter pittii (1.7%), Acinetobacter guillouiae (1.1%), as well as a new potential species named "Candidatus Acinetobacter pediculi".

CONCLUSIONS

To our knowledge, this study reports for the first time, the presence of clade E head lice in DR Congo. This study is also the first to report the presence of Acinetobacter species DNAs in human head lice in DR Congo.

Lung function in children with sickle cell disease from Central Africa

Lung function in patients with sickle cell anaemia (SCA) living in sub-Saharan Africa is largely unknown. Anthropometry and spirometry were cross-sectionally evaluated in patients with SCA (HbSS) aged 6–18 years and in schoolchildren from the Democratic Republic of the Congo. The Global Lung Initiative 2012 spirometry reference values were used. A total of 112 patients and 377 controls were included. Twenty-six per cent of patients with SCA had spirometry findings suggestive of a restrictive pattern and 41% had a FEV1 z-score <5th percentile. Wasting, increasing age and female sex were independently associated with increased risk of restrictive spirometry pattern in patients with SCA. Longitudinal studies could clarify the prognostic meaning of these findings.

Evaluation of the Global Lung Initiative 2012 Reference Values for Spirometry in African Children

RATIONALE

Despite the high burden of respiratory disease, no spirometry reference values for African children are available.

OBJECTIVES

Investigate whether the Global Lung Initiative (GLI-2012) reference values for spirometry are appropriate for children in sub-Saharan Africa and assess the impact of malnutrition on lung function.

METHODS

Anthropometry and spirometry were obtained in children aged 6 to 12 years from urban and semiurban schools in three African countries. Spirometry z-scores were derived using the GLI-2012 prediction equations for African Americans. Thinness (body mass index z-score < -2) was a surrogate for malnutrition. Spirometry outcomes were compared with those of African American children from the third National Health and Nutrition Survey.

MEASUREMENTS AND MAIN RESULTS

Spirometry data were analyzed from 1,082 schoolchildren (51% boys) aged 6.0 to 12.8 years in Angola (n = 306), Democratic Republic of the Congo (n = 377), and Madagascar (n = 399). GLI-2012 provided a good fit with mean (SD) z-scores of -0.11 (0.83) for FEV₁, -0.08 (0.86) for FVC, and -0.07 (0.83) for FEV₁/FVC. Because of low scatter, the fifth centile corresponded to -1.3 z-scores in boys and -1.5 z-scores in girls. Malnourished African children had a normal FEV₁/FVC ratio but significant reductions of ∼0.5 z-scores (∼5%) in FEV₁ and FVC compared with African American peers from the third National Health and Nutrition Survey. Children in Angola had the lowest, and those in Madagascar had the highest, zFEV₁ and zFVC.

CONCLUSIONS

The results of this study support the use of GLI-2012 reference values for schoolchildren in sub-Saharan Africa. Malnutrition affects body growth, leading to a proportionately smaller FEV₁ and FVC without respiratory impairment, as shown by the normal FEV₁/FVC ratio.

[Hemogram findings in Congolese children with sickle cell disease in remission]

INTRODUCTION

Sickle cell disease is associated with a wide range of clinical and laboratory findings depending on genetic modulators and environmental factors. The most severe forms of sickle cell disease occur in patients with the Bantu haplotype. The purpose of this study was to determine the hematological profile of Congolese patients with homozygous sickle cell disease during periods of remission.

PATIENTS AND METHODS

Hemograms were performed in two series of patients with sickle cell disease in remission, i.e., one including 89 patients with a mean age of 8.7 years and the other including 42 patients with a mean age of 8.9 years. Hemograms were performed using an automated counter and reticulocytes were counted manually on peripheral blood smears. Fetal hemoglobin level (HbF) was measured by chromatography (HPLC). The mean values obtained were compared with those obtained in a sickle-cell-disease-free control group. Some parameters were also compared with those obtained in a group of patients exhibiting complications of sickle cell disease.

RESULTS

Hemograms in the first series of patients demonstrated the following values: Hb: 7.2 g/dl; Hct 23.1%, red cells: 2.47 tera/L, leukocytes: 14.9 giga/L; VGM: 95.3 fL; CCMH:30.3% L and platelets:345,3 giga/L. Blood count showed 30.4% of polynuclear neutrophils, 33% de lymphocytes, 0.8% of polynuclear basophiles, 14% of monocytes, 7.8% of polynuclear eosinophils and 14% of erythroblasts. Mean HbF level was 7.2% and reticulocytes were at 88%. In the sickle cell disease-free group, the leukocyte rate was almost three fold higher than in the patient group exhibiting sickle cell disease in remission even though rates were higher than during complications.

CONCLUSION

Hemogram profiles in Congolese patients with sickle cell disease are similar to those reported in the literature for subjects exhibiting the Bantou haplotype. Leukocytosis was associated with esinophilia and monocytosis suggested a topical state and chronic inflammation.

Laryngeal Mask Airway for neonatal resuscitation in a developing country: evaluation of an educational intervention. Neonatal LMA: an educational intervention in DRC

Background

Studies carried out in developing countries have indicated that training courses in newborn resuscitation are efficacious in teaching local birth attendants how to properly utilize simple resuscitation devices. The aim of this study was to assess the knowledge and expertise gained by physicians and midwifes who participated in a Neonatal Resuscitation Course and workshop organized in a Third World Country on the use of Laryngeal Mask Airway (LMA).

Methods

A 28-item questionnaire, derived from the standard test contained in the American Heart Association and the American Academy of Pediatrics Neonatal Resuscitation Manual, was administered to 21 physicians and 7 midwifes before and after a course, which included a practical, hands-on workshop focusing on LMA positioning and bag-ventilation in a neonatal manikin.

Results

The knowledge gained by the physicians was superior to that demonstrated by the midwifes. The physicians, in fact, demonstrated a significant improvement with respect to their pre-course knowledge. Both the physicians and the midwives showed a good level of expertise in manipulating the manipulating the manikin during the practical trial session. The midwifes and physicians almost unanimously manifested a high degree of approval of neonatal resuscitation by LMA, as they defined it a sustainable and cost-effective method requiring minimal expertise.

Conclusions

Further studies are warranted to test the advantages and limits of the neonatal LMA training courses in developing countries.

[Human papillomavirus genotype profile in Kinshasa, Democratic Republic of the Congo: implications for vaccination]

Proposed anti-human papillomavirus (HPV) vaccines, i.e., Cervarix (Glaxomith-Kline) and Gardasil (Merck), are designed to prevent infection by two high-risk HPV types, i.e., 16 and 18, for which estimation mainly in Western Europe and North America have demonstrated a prevalence 60 to 70%.

OBJECTIVE

The purpose of this study was to determine the genotype profile of HPV strains encountered in the women of childbearing age in Kinshasa, Democratic Republic of the Congo and discuss the implications of this profile for anti-HPV vaccination.

METHODS

Data and specimen collection was carried out at a voluntary HIV screening and treatment facility. Genotyping of HPV was performed in 55 patients presenting dysplastic lesions of the uterine cervix including 47 (85.5%) who were HIV-seropositive. Detection and typing of HPV were performed using the Inno-Lipa technique (Innogenetics Line Probe Assay) from Glaxo-Smith-Kline.

RESULTS

Tests for HPV were positive in 54 patients (98.2%). A total of 153 HPV strains were isolated. Twenty-three HPV types were identified including 83.0% with high oncogenic activity. In order of frequency the oncogenic types were as follows: 68, 35, 51, 52, 16, 31, 18, 17, 33, 45, 56, 58 and 59. Strain frequency per patient ranged from 1 to 8 (mean +/- standard deviation, 2.8 +/- 2,0). Types 16 and 18 accounted for 11.8% of the isolated strains (18/153) and were observed in 33.3% of patients (18/54).

CONCLUSION

The findings of this study suggest that the HPV genotype profile in Kinshasa differs from the profile observed in Western Europe and North America. If confirmed by larger-scale studies, this result bodes poorly for the efficacy of anti-HPV vaccines in Kinshasa.

[Is therapeutic progress in the management of sickle cell disease applicable in sub-Saharan Africa?]

The life expectancy of patients with sickle cell disease has improved in the United States and Europe thanks to the use of penicillin prophylaxis, appropriate immunizations, neonatal screening, implementation of a quality transfusional policy, hydroxyurea therapy, detection and treatment of cerebral vasculopathy, recognition of situations that can benefit from allogenic marrow transplantation, and improvements in bone marrow transplantation techniques. The cost of almost all these techniques is far beyond the means of health care systems in Africa where they cannot be used. However at least three, i.e., penicillin, vaccines, and hydroxyurea, could be easily accessible in the framework of defined therapeutic strategies. If daily penicillin and pneumococcal vaccine Pneumo 23 are required, it would likely be necessary to select a conjugated vaccine other than Prevenar that does not provide protection against all strains present in Africa. Neonatal screening is still a rare procedure in sub-Saharan countries. Periodic transfusion is steadily improving but exchange transfusion programs aimed in particular at preventing neurological complications are still unfeasible. Indications for hydroxyurea therapy in Africa are more common due to the lack of access to chronic transfusion and must be based on consensus decision. Use of bone marrow transplantation, i.e., the only currently available curative treatment, is still possible only in northern hemisphere countries where it is still restricted to children with severe forms and an HLA-compatible family donor.

[Medicine and health in the Democratic Republic of Congo: from Independence to the Third Republic]

The birth and mortality rates in the Democratic Republic of Congo (DRC), a former Belgian colony, are high, i.e., 48.9/1000 and 17/1000 respectively. The DRC also has one of the highest maternal death rates in the world, i.e., 1289/100,000 live births. Health conditions have not improved since independence. Access to drinking water is limited, living conditions are poor, and food availability in households is low. The mean health services utilization rate in the DRC is estimated to be 0.15 visits/inhabitant/year. The incidence of transmissible diseases is rising. This increase is observed even for illnesses that were under control before independence such as sleeping sickness, onchocerciasis, leprosy, and tuberculosis. One the main causes of mortality and morbidity in the population is malaria that is responsible for the deaths of 150,000 to 250,000 children under the age of 5 every year. The HIV prevalence rate is 4.5% with 1.19 million persons with AIDS and 930,000 orphans whose parents died of AIDS. Other potentially epidemic diseases including bubonic plaque and Ebola hemorrhagic fever are serious threats. Non-transmissible diseases are also on the rise including diabetes, systemic arterial hypertension, cancer and neglected diseases such as sickle cell anemia. To meet these challenges, the country's health authorities have established a program called the Strategy for Reinforcement of the Health System (SRHS). One goal of the SRHS is to develop health zones in order to improve access to quality health care for the whole population.

Newborn screening for haemoglobinopathies: the Brussels experience

OBJECTIVES

To determine the prevalence of haemoglobinopathies and the need for neonatal screening for haemoglobinopathies in Brussels.

METHODS

Between December 1994 and June 1998 23,136 cord blood samples obtained in eight hospital nurseries of Brussels were systematically screened for haemoglobinopathies by isoelectric focusing.

RESULTS

45% of the newborns were from regions at risk for haemoglobinopathies. Sickle cell disease was diagnosed for 11 neonates (0.048%) and beta thalassaemia major for one neonate. Three hundred and fifty neonates (1.5%) were carriers for a haemoglobin variant, and Hb Bart's was found in 672 cases (2.9%). These prevalences are similar to those reported elsewhere in northern Europe.

CONCLUSIONS

These results confirm the value of universal screening for haemoglobinopathies in Brussels.

[Hereditary spherocytosis: one year study of erythrocyte membrane proteins]

Hereditary spherocytosis (HS) is a congenital hemolytic anemia which affects one person out of 5000 in Northern Europe. HS is caused by defects of the red cell membrane proteins involving mainly ankyrin or band 3, and less frequently, protein 4.2 or spectrin. The reduction of red cell osmotic resistance and the recognition of spherocytes on the peripheral blood smear are the primary laboratory tests necessary to evocate a diagnosis of hereditary spherocytosis. Analysis of the red cell membrane proteins using polyacrylamide gel electrophoresis is used to quantify individual proteins and to identify the protein defect related to a diagnosis of HS. Samples from 47 patients and 25 controls were studied by electrophoresis of the red cell membrane proteins. Protein deficiencies related to HS were demonstrated for 21 patients. In 4 other cases, abnormalities of membrane proteins unrelated to HS were also demonstrated. Electrophoresis of the red cell membrane proteins allows the identification of the protein deficiency related to HS and thus confirms the diagnosis of HS, but also points to the underlying molecular defect, the inheritance pattern and the clinical aspects of the disease.

Globin chains analysis: improved resolution by electrophoresis in urea-acetic acid-Triton X-100

To improve the resolution and rapidity of globin chains separation, we have modified the basic technique of globin chain electrophoresis in urea-acetic acid-Triton X-100. Haemolysates from anticoagulated cord or adult blood samples were submitted to urea-acetic acid-Triton X-100 polyacrylamide gel electrophoresis using a 15% polyacrylamide gel cast in a mini slab cell which allows a rapid analysis of globin chains samples. After staining proteins with Coomassie brilliant blue R-250, the relative amounts of globin chains were determined by scanning. This new procedure has allowed us to obtain a better separation of the normal and abnormal globin chains than described previously. All the normal globin chains, i.e. A gamma, G gamma, delta, beta and alpha, are well separated by this modified technique. Semi-quantification of the G gamma/A gamma ratio has been performed. This simple and rapid method is also suitable for the global identification of the globin chain involved in the most common abnormal haemoglobin variants, except beta-S.

Structural and functional studies of hemoglobin Moabit (alpha 86(F7) Leu-->Arg

An abnormal hemoglobin fraction was detected on high performance liquid chromatography profile performed for the measurement of glycated hemoglobin in a 55-year-old caucasian patient. The structural and functional studies were performed by standard techniques. Separation of hemoglobins by alkaline electrophoresis and by IEF revealed a slightly more rapid fraction than does Hb S. By acid electrophoresis, no abnormal Hb fraction could be observed. Separation of globin chains by electrophoresis demonstrated an alpha-chain variant and by chromatography, a fraction which eluted between beta and gamma globin chains. Tryptic digests and amino acid analysis have demonstrated a previously described substitution of Leu-->Arg alpha 86(F7).

[Neonatal screening for hemoglobinopathies in the Brussels region]

We realised this study in order to determine the frequency of abnormal haemoglobins and to appreciate the need for a neonatal screening for haemoglobinopathies in Brussels. Over a two year-period, 9575 cord blood samples were systematically screened. The study disclosed following results : 40% of newborns were from regions at risk for haemoglobinopathies and abnormal haemoglobins were present in 2.5% of the neonates tested. This frequency is similar to those reported elsewhere in North Europe. The most frequent abnormal haemoglobins were the Hb S, Bart's, C, D and E. Three cases of severe forms of sickle cell anaemia were identified. The frequency of abnormal haemoglobins and Hb S traits combined to the high rate of mixed marriages (16%) justifies the need for a universal screening for haemoglobinopathies in Brussels.

[Sickle cell anemia in the south of Zaire. Study of two series of 251 and 340 patients followed-up 1988-1992]

BACKGROUND

This work concerns 591 sickle cell disease patients followed by the same paediatrics team in south Zaire.

POPULATION

Two series of homozygous sickle cell patients were studied: 1) 251 in-patients hospitalized in Kolwezi during the period 1988-1989, and 2) 340 out-patients examined in Lubumbashi during the period 1990-1992.

RESULTS

In the first series, a high proportion of children aged 3-5 years (30.7%) and 6-12 years (54%) was observed in comparison with a control group of patients hospitalized for anemia at the same time. The symptoms of the disease occurred during the first year of life in 80% of the children: hand-foot syndrome and/or anemia. Tooth decay was observed as soon as the age of 3 years with a high frequency (62%) as compared with the control group. Epistaxis, sometimes very important, was observed in 39.5% and 52% of the cases in children respectively aged 6-12 years and up to 13. A splenomegaly was noted during a longer period than in the control group, suggesting associated causing factors different from malaria, perhaps alpha thalassemia. The high frequency of viral contaminations due to transfusion is illustrated by the seropositivity prevalences of HIV (11.5%), HBV (10%) and in the children in Lubumbashi.

CONCLUSION

The main interest of these series of children is to point out the clinical specificities of a cohort genetically homogenous, offering the opportunity of defining basis of inter-individual variability of sickle cell disease.