Prevalence of sickle cell disease in a pediatric population suffering from severe infections: a Congolese experience

The gut microbiome in sickle cell disease: Characterization and potential implications

BACKGROUND

Sickle Cell Disease (SCD) is an inherited blood disorder that leads to hemolytic anemia, pain, organ damage and early mortality. It is characterized by polymerized deoxygenated hemoglobin, rigid sickle red blood cells and vaso-occlusive crises (VOC). Recurrent hypoxia-reperfusion injury in the gut of SCD patients could increase tissue injury, permeability, and bacterial translocation. In this context, the gut microbiome, a major player in health and disease, might have significant impact. This study sought to characterize the gut microbiome in SCD.

METHODS

Stool and saliva samples were collected from healthy controls (n = 14) and SCD subjects (n = 14). Stool samples were also collected from humanized SCD murine models including Berk, Townes and corresponding control mice. Amplified 16S rDNA was used for bacterial composition analysis using Next Generation Sequencing (NGS). Pairwise group analyses established differential bacterial groups at many taxonomy levels. Bacterial group abundance and differentials were established using DeSeq software.

RESULTS

A major dysbiosis was observed in SCD patients. The Firmicutes/Bacteroidetes ratio was lower in these patients. The following bacterial families were more abundant in SCD patients: Acetobacteraceae, Acidaminococcaceae, Candidatus Saccharibacteria, Peptostreptococcaceae, Bifidobacteriaceae, Veillonellaceae, Actinomycetaceae, Clostridiales, Bacteroidacbactereae and Fusobacteriaceae. This dysbiosis translated into 420 different operational taxonomic units (OTUs). Townes SCD mice also displayed gut microbiome dysbiosis as seen in human SCD.

CONCLUSION

A major dysbiosis was observed in SCD patients for bacteria that are known strong pro-inflammatory triggers. The Townes mouse showed dysbiosis as well and might serve as a good model to study gut microbiome modulation and its impact on SCD pathophysiology.

[Acceptability of neonatal screening of the sickle cell disease during the pandemic of COVID-19 in Kisangani, Democratic Republic of the Congo]

Introduction

l´implémentation du dépistage néonatal de la drépanocytose pendant la pandémie de coronavirus (COVID-19) représente un défi majeur en République Démocratique du Congo (RDC). La présente étude vise à déterminer si des facteurs socio-économiques sont associés à l´acceptabilité du dépistage néonatal de la drépanocytose pendant la COVID-19 à Kisangani, en RDC.

Méthodes

étude observationnelle conduite dans les maternités de Kisangani du 21 mars au 30 juin 2020 chez les mères sensibilisées au dépistage néonatal de la drépanocytose de leurs nouveau-nés à l´hemotypeSC^TM (HT401RUO-USA). Les données recueillies étaient la parité, le niveau d´étude, l´âge, le niveau socio-économique, la profession, la notion de sensibilisation et le motif du refus du dépistage.

Résultats

sur 55,5% (273/492) des mères sensibilisées, 107 (39,19 %) ont accepté et 166 (60,80 %) ont refusé le dépistage néonatal de la drépanocytose chez leur nouveau-né. Les motifs du refus étaient l´absence d´information (67,5%; IC 95% [59,8-74,5]), le manque d´argent dû au confinement (66,3%; IC 95% [58,5-73,4]), la prise de sang pour tentative du vaccin anti-COVID-19 (63,2%; IC 95% = [55,4-70,6]). Les facteurs associés à l´acceptabilité du dépistage étaient l´âge > 35 ans (p = 0,0009; ORa = 3,04; IC 95% = 1,57-5,87) et le bas niveau socio-économique (p = 0,0016; ORa = 2,29; IC à 95% = 1,37-3,85).

Conclusion

l´acceptabilité du dépistage néonatal de la drépanocytose pendant la COVID-19 reste faible à Kisangani. Le gouvernement devrait identifier les canaux de communication efficaces afin de promouvoir les initiatives dans le secteur de la Santé.

Children with sickle cell disease migrating to the United States from sub-Saharan Africa

Sickle cell disease (SCD) is an inherited red blood cell disorder that occurs worldwide and results in significant morbidity and mortality. In addition to affected children who are born in the US, an increasing number of children with SCD are migrating to the US with their families or through international adoption. Children arriving as immigrants or refugees have unique medical and psychosocial challenges that require a multidisciplinary team approach which takes into account the family's primary language, culture, and health beliefs. This review focuses on the special challenges for children with SCD who emigrate from sub-Saharan Africa to the US.

[Awareness and attitudes of 50 congolese families affected by sickle cell disease: a local survey]

Introduction

Sickle cell disease is a very common disease in the Democratic Republic of the Congo, but it is poorly known despite having an impact on the morbi-mortality. Our study aimed to evaluate the extent of awareness and attitudes of families affected by sickle cell disease as well as the impact of this disease in their daily lives.

Methods

We conducted a cross-sectional study of a unique non-random sampling from 50 families affected by sickle cell disease in Mbujimayi, Democratic Republic of the Congo, from 15 June to 15 August 2015. Participants were interviewed using a standardized questionnaire.

Results

This study focuses on 50 families affected by sickle cell disease; medical characteristics were found only in first children affected by sickle cell disease in each household. Less than 10% of families had minimally ill children. Fifty families were interviewed, of whom 22 had more than one child with sickle cell disease. The average age at diagnosis was 1 years. Diagnosis was based on clinical examination in 42% (21) of cases. Each first child affected by sickle cell disease had an average of 3.4 crises per year, 4 episodes of fever per year, received an average of 1.9 transfusions per year and was hospitalized an average of 3 times per year. Thirty-one families (62%) didn't have sufficient monthly income to help their children to manage sickle cell disese, 48 (96%) families hoped that a reference sickle cell centre would be established in Mbujimayi and 47 (94%) would accept to subscribe to health insurance if the annual amount were between $50 and $100.

Conclusion

The extent of awareness among families directly affected by sickle cell disease in Mbujimayi, Democratic Republic of the Congo, is low. This has a direct impact on the management of children with sickle cell disease. The socioeconomic status of these families is also a factor which should be taken into account. The establishement of a reference center and the possibility to fix an annual amount for the treatment of patients would be a strategic approach to implement the awareness and the attitudes of families in relation to this disease having a direct impact on the morbi-mortality of patients.

Serum Soluble Transferrin Receptor Concentrations Are Elevated in Congolese Children with Glucose-6-Phosphate Dehydrogenase Variants, but Not Sickle Cell Variants or α-Thalassemia

Background: Anemia is common in Congolese children, and inherited blood disorders may be a contributing cause. The presence of sickle cell variants, X-linked glucose-6-phosphate dehydrogenase (G6PD) deficiency and α-thalassemia, has been previously reported. G6PD A- deficiency is characterized by the co-inheritance of G6PD 376 and 202 variants and is common in sub-Saharan Africa.Objective: We aimed to measure the associations between inherited blood disorders and hemoglobin, ferritin, and soluble transferrin receptor (sTfR) concentrations in Congolese children.Methods: Venous blood was collected from 744 children aged 6-59 mo from 2 provinces. We measured biomarkers of nutritional and inflammation status and malaria. Pyrosequencing was used to detect sickle cell variants. Polymerase chain reaction was used to detect G6PD variants and α-thalassemia deletions.Results: Overall, 11% of children had a sickle cell variant, 19% of boys were G6PD A- hemizygotes, 12% and 10% of girls were G6PD A- hetero- or homozygotes, respectively, and 12% of children had α-thalassemia. Multivariable linear regression models (adjusted for age, province, altitude, malaria, and biomarkers of nutritional and inflammation status) showed that G6PD A- hemizygous boys and G6PD 376 homozygous girls had higher sTfR concentrations [geometric mean ratios (95% CIs): 1.20 (1.03, 1.39) and 1.25 (1.02, 1.53), respectively] than children with no G6PD variants. Hemoglobin and ferritin concentrations were not independently associated with any of the inherited blood disorder genotypes.Conclusions: We found that 2 G6PD variant genotypes were associated with elevated sTfR concentrations, which limits the accuracy of sTfR as a biomarker of iron status in this population.

Acute Crises and Complications of Sickle Cell Anemia Among Patients Attending a Pediatric Tertiary Unit in Kinshasa, Democratic Republic Of Congo

In the Democratic Republic of Congo, the incidence of sickle cell anemia (SCA) is estimated to affect 30,000 to 40,000 neonates per year. However, there is paucity of data on acute clinical manifestations in sickle cell children. In these circumstances, it is difficult to develop a health care policy for an adequate management of sickle cell patients. This was a seven years’ retrospective study of children admitted with acute sickle cell crisis in the Department of Pediatrics in University Hospital of Kinshasa, Kinshasa, the Democratic Republic of Congo. A total of 108 patients were identified as having SCA. There were 56 (51%) girls and 52 (49%) boys. Median age was 10.5 years (range 1-24 years). No child was diagnosed by neonatal screening. The median age of diagnosis of sickle cell anemia was 90 months (range: 8-250 months). The median age at the first transfusion was 36 months (range 4-168). In this series, 61 (56.5%) patients were eligible for hydroxyurea. However, this treatment was only performed in 4 (6.6%) of them. Pain episodes, acute anemic crisis and severe infection represent respectively 38.2%, 34.3% and 21.9% of events. Altered sensorium and focal deficit were encountered occasionally and represented 3.4% of acute events. Acute renal manifestations, cholelithiasis and priapism were rarely reported, in this cohort. In Kinshasa, the care of patients suffering from sickle cell anemia is characterized by the delayed diagnosis and low detection of organ complications compared to reports of Western countries. This situation is due to resources deficiencies.

Validity of simple clinical and biological parameters as screening tool for sickle cell anemia for referral to tertiary center in highly resource constraints

BACKGROUND

In the Democratic Republic of Congo, the incidence of sickle cell anemia (SCA) is estimated around 40 000 neonates per year. However, it is notoriously difficult to perform conventional electrophoresis in all hospitals and laboratories, especially at peripheral levels and rural area. A panel of multiple clinical and laboratory features that would enhance sickle cell disease were assessed for the detection of the disease in highly resource-scarce settings.

METHODS

A prospective study was conducted in Kinshasa. Venous blood samples were drawn from each study participant in order to determine the hematologic parameters, the peripheral smears, and the hemoglobin electrophoresis. We used Cohen's κ statistic to examine the agreement of each variable and diagnosis of sickle cell disease.

RESULTS

A total of 807 patients were screened for sickle cell disease. Among these 807 children, 36 (4.5%) were homozygous for Hb S disease. The presence of at least 8% erythroblasts (PPV: 91%, NPV: 99%, sensitivity: 83.3%, specificity: 99.6%, κ value: .86) and sickle cells (PPV:100%, NPV: 98%, sensitivity: 50%, specificity: 100%, κ value: .66) in the peripheral blood smear had an acceptable agreement for sickle cell disease.

CONCLUSION

These two biological markers may guide the clinician in the decision-making to initiate the management of the children as a sickle cell patient, pending confirmation of the disease by electrophoresis techniques.