[Platelet count in the steady state phase and clinical severity of sickle cell disease in a reference centre for sickle cell disease in Mali]

Risk factors associated with complications occurring in sickle cell disease are not fully elucidated. The purpose of this study was to evaluate the existence of an association between the clinical severity of sickle cell disease and platelet count in the steady state phase in patients with sickle cell disease followed up at the Center for Research and Control of Sickle Cell Disease in Bamako, Mali. We conducted a retrospective review of 40 medical records of patients aged 5 to 42 years with sickle cell disease at the Center for Research and Control of Sickle Cell Disease in Bamako, Mali. Clinical severity of sickle cell disease was assessed according to the criteria of VOC and/or hospitalizations < 2 or ≥ 2 per year. Data entry was carried out using the Excel 2013 version. The statistical tests used were the Chi2, Student and Mac Nemar tests. Of the 40 patients, 82.5% had haemolytic phenotype and 17.5% hyperviscous phenotype; complications of sickle cell disease were more frequent in the haemolytic phenotype group (p < 0.05). There was a significant association between mean platelet count ≥ 450 G/L in the steady state phase and the annual number of CVOs ≥ 2 (p = 0.002). This study shows that mean platelet count ≥ 450 G/L in sickle cell patients in the steady state phase could be a risk factor for the frequent occurrence of CVO. It underlines the importance of conducting prospective studies focusing on both hyperplateletosis and platelet activation markers in larger sample sizes, as well as therapeutic trials involving platelet activation inhibitors, such as Crizanlizumab, a humanised anti-P-selectin monoclonal antibodies.

Sickle Cell Disease: Metabolomic Profiles of Vaso-Occlusive Crisis in Plasma and Erythrocytes

The metabolomic profile of vaso-occlusive crisis, compared to the basal state of sickle cell disease, has never been reported to our knowledge. Using a standardized targeted metabolomic approach, performed on plasma and erythrocyte fractions, we compared these two states of the disease in the same group of 40 patients. Among the 188 metabolites analyzed, 153 were accurately measured in plasma and 143 in red blood cells. Supervised paired partial least squares discriminant analysis (pPLS-DA) showed good predictive performance for test sets with median area under the receiver operating characteristic (AUROC) curves of 99% and mean p-values of 0.0005 and 0.0002 in plasma and erythrocytes, respectively. A total of 63 metabolites allowed discrimination between the two groups in the plasma, whereas 61 allowed discrimination in the erythrocytes. Overall, this signature points to altered arginine and nitric oxide metabolism, pain pathophysiology, hypoxia and energetic crisis, and membrane remodeling of red blood cells. It also revealed the alteration of metabolite concentrations that had not been previously associated with sickle cell disease. Our results demonstrate that the vaso-occlusive crisis has a specific metabolomic signature, distinct from that observed at steady state, which may be potentially helpful for finding predictive biomarkers for this acute life-threatening episode.

[Targeted newborn screening for sickle-cell anemia: Sickling test (Emmel test) boundaries in the prenatal assessment in West African area]

BACKGROUND

Newborn screening for sickle cell anemia is necessary in Africa where the disease is more frequent. Hemoglobin electrophoresis is used for screening, but is limited by a high cost and difficult access. Sickling test (Emmel test), which is more affordable and technically more accessible, is often requested for prenatal assessment of pregnant women in West African areas to reserve screening for newborns from mothers in whom the positive sickling test attests the presence of hemoglobin S. This study aims to evaluate the number of undetected sickle cell anemia newborns by a screening policy targeting only newborns from mothers in whom a sickling test would have been positive.

METHODS

From 2010 to 2012, in Bamako, Mali, West Africa, 2489 newborns were routinely screened for sickle cell anemia at the umbilical cord or heel by isoelectrofocusing and, if necessary, by high-performance liquid chromatography. These newborns were born from 2420 mothers whose hemoglobin was studied by isoelectrofocusing. The data was recorded and processed using Excel software version 14.0.0. We calculated the frequency of the sickle cell gene in mothers and newborns as well as the number of SCA newborns from heterozygous or C homozygous mothers.

RESULTS

Of the 2489 newborns, 16 had sickle cell anemia (6 SS and 10 SC); 198 had the sickle cell trait; 139 were AC and 1 was CC. Of the 10 newborns with SC profile, 3 were born from mothers not carrying the S gene but the C gene of hemoglobin and in which an Emmel test would have been negative.

CONCLUSION

Targeted newborn screening, based on the results of sickling test in pregnant women, would misdiagnose more than one of six sickle cell anemia newborns who would not benefit from early care. Cost-effectiveness studies of routine newborn screening for sickle cell anemia should lead to a better screening strategy in contexts where hemoglobin S and other hemoglobin defect genes coexist.

[Sickle cell anemia and transfusion safety in Bamako, Mali. Seroprevalence of HIV, HBV and HCV infections and alloimmunization belonged to Rh and Kell systems in sickle cell anemia patients]

Red cell transfusion is one of the main treatments in sickle cell disease. However there are potential risks of blood transfusions. In order to propose strategies to improve blood safety in sickle cell disease in Mali, we conducted a prospective study of 133 patients with sickle cell anemia recruited at the sickle cell disease research and control center of Bamako, November 2010 to October 2011. The study aimed to determine the prevalence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infections by serum screening and the frequency of red cell alloimmunization before and after blood transfusion. The diagnosis of sickle cell syndrome was made by HPLC, the detection of markers of viral infection was performed by ELISA, and the diagnosis of alloimmunization was conducted by the Indirect Coombs test. Prevalence of viral infections observed at the time of enrolment of patients in the study was 1%, 3% and 1% respectively for HIV, HBV and HCV. Three cases of seroconversion after blood transfusion were detected, including one for HIV, one for HBV and one another for HCV in sickle cell anemia patients. All these patients had received blood from occasional donors. The red cell alloimmunization was observed in 4.4% of patients. All antibodies belonged to Rh system only. Blood transfusion safety in sickle cell anemia patients in Mali should be improved by the introduction of at least the technique for detecting the viral genome in the panel of screening tests and a policy of transfusions of blood units only from regular blood donors.

High incidence of triple-negative tumors in sub-saharan Africa: a prospective study of breast cancer characteristics and risk factors in Malian women seen in a Bamako university hospital

OBJECTIVE

Few studies have been conducted on breast cancer in Sub-Saharan Africa and their results have been suspected to be impaired by artefacts. This prospective study was designed to determine tumor and patient characteristics in Mali with control of each methodological step. These data are necessary to define breast cancer treatment guidelines in this country.

METHODS

Clinical and tumor characteristics and known risk factors were obtained in a consecutive series of 114 patients. Each technical step for the determination of tumor characteristics [histology, TNM, grade, estrogen (ER) and progesterone receptors (PR), HER2, and Ki67] was controlled.

RESULTS

Patients had a mean age of 46 years. Most tumors were invasive ductal carcinomas (94%), T3-T4 (90%) with positive nodes (91%), grade III (78%), and ER (61%) and PR (72%) negative. HER2 was overexpressed in 18% of cases. The triple-negative subgroup represented 46%, displaying a particularly aggressive pattern (90% grade III; 88% Ki67 >20%).

CONCLUSION

This study demonstrates the high incidence of aggressive triple-negative tumors in Mali. Apart from a higher prevalence of premenopausal women, no significant difference in risk factors was observed between triple-negative tumors and other tumors. The hormonal therapy systematically prescribed therefore needs to be revised in light of this study.