Differences of microparticle patterns between sickle cell anemia and hemoglobin SC patients.

Sickle cell anemia (SCA) and hemoglobin SC (HbSC) disease are the two most common forms of sickle cell disease (SCD), a frequent hemoglobinopathy which exhibits a highly variable clinical course. Although high levels of microparticles (MPs) have been consistently reported in SCA and evidence of their harmful impact on the SCA complication occurrences have been provided, no data on MP pattern in HbSC patients has been reported so far. In this study, we determined and compared the MP patterns of 84 HbSC and 96 SCA children, all at steady-state, using flow cytometry. Most of circulating MPs were derived from platelets (PLTs) and red blood cells (RBCs) in the two SCD syndromes. Moreover, we showed that HbSC patients exhibited lower blood concentration of total MPs compared to SCA patients, resulting mainly from a decrease of MP levels originated from RBCs and to a lesser extent from PLTs. We did not detect any association between blood MP concentrations and the occurrence of painful vaso-occlusive crises, acute chest syndrome and pulmonary hypertension in both patient groups. We also demonstrated for the first time, that whatever the considered genotype, RBC-derived MPs exhibited higher externalized phosphatidylserine level and were larger than PLT-derived MPs

Newborn Screening for Sickle Cell Disease in the Caribbean: An Update of the Present Situation and of the Disease Prevalence

International audienceThe region surrounding the Caribbean Sea is predominantly composed of island nations for its Eastern part and from the American continental coast on its Western part. A large proportion of the population, particularly in the Caribbean islands, traces its ancestry to Africa as a consequence of the Atlantic slave trade during the XVI-XVIII centuries. As a result, sickle cell disease has been largely introduced in the region. Some Caribbean countries and/or territories such as Jamaica and the French territories initiated newborn screening (NBS) programs for sickle cell disease more than 20 years ago. They have demonstrated the major beneficial impact on mortality and morbidity resulting from early childhood care. However, similar programs have not been implemented in much of the region. This paper presents an update of the existing NBS programs and the prevalence of sickle cell disease in the Caribbean. It demonstrates the impact of the Caribbean Network of Researchers on Sickle Cell Disease and Thalassemia (CAREST) on the extension of these programs. The presented data illustrate the importance of advocacy in convincing policy makers of the feasibility and benefit of NBS for sickle cell disease when coupled to early care

CAREST—Multilingual Regional Integration for Health Promotion and Research on Sickle Cell Disease and Thalassemia

International audienceSickle cell disease (SCD) is a significant problem in the Caribbean, where many individuals have African and Asian forebears. However, reliable prevalence data and specific health care programs for SCD are often missing in this region. Closer collaboration between Caribbean territories initiated in 2006 to set up strategies to promote better equity in the health care system for SCD patients led to the formation of CAREST: the Caribbean Network of Researchers on Sickle Cell Disease and Thalassemia. We present the effectiveness of collaborations established by CAREST to promote SCD newborn screening programs and early childhood care, to facilitate health worker training and approaches for prevention and treatment of SCD complications, and to carry out inter-Caribbean research studies

Biological and clinical characteristics of the SCD studied patients.

<p>Biological and clinical characteristics of the SCD studied patients.</p

Correlation between MP concentrations and markers of hemolysis/anemia in SCD patients.

<p>Correlation between MP concentrations and markers of hemolysis/anemia in SCD patients.</p

Cellular origins and blood MP concentrations of SCA and HbSC patients.

<p>Cellular origins and blood MP concentrations of SCA and HbSC patients.</p

MP characterization by flow cytometry.

<p><b>A</b>: Acquisition gate (H) was based on forward- and side-scatter values of 0.9 mm-large calibration beads; <b>B</b>: autofluorescence was determined using isotopic control (IgG-PE); <b>C</b>: platelet-derived MPs or <b>D</b>: erythrocyte-derived MPs were labelled with FITC-annexin-V (FL1) and PE-conjugated monoclonal antibodies directed against CD41 or CD235a, respectively.</p

Comparison of total MP concentrations between not HC-treated SCA and HbSC patients classified according to the occurrence of VOC, ACS and abnormal TRJV.

<p><b>A</b>: Not HC-treated SCA children classified according to VOC, ACS and TRJV ≥ 2.5 m/s occurrences respectively. <b>B</b>: HbSC children classified according to VOC ACS and TRJV ≥ 2.5 m/s occurrences respectively. Blood total MP concentrations are represented as median with interquartile range.</p

Comparison of RBC- and PLT-derived MP characteristics between SCA and HbSC patients.

<p><b>A</b>: mean fluorescence intensity of annexin V; <b>B</b>: mean forward scatter index. The value distributions are represented as box and whiskers (min to max). ****: p < 10⁻⁴.</p

“CAREST”- Caribbean network of researchers on sickle cell disease and thalassemia: a regional organisation for health promotion and research.

International audienc