Clinical outcome and incidence of inhibitor development in severe hemophilia patients receiving low-dose prophylaxis: a 3-year follow-up study in Senegal, West Africa

ABSTRACT Introduction: In Africa, where access to diagnosis and treatment of hemophilia is the lowest in the world, prophylaxis is rarely used in preference to on-demand treatment. There are limited data of prophylaxis treatment from sub-Saharan Africa. The aim of this study was to evaluate clinical outcomes and inhibitor development in people with hemophilia receiving low-dose prophylaxis (LDP) in a sub-Saharan African setting. Methods: We conducted a three-year prospective study. A once or twice weekly prophylaxis regimen of 25 IU/kg of rFVIIIFc or 30 IU/kg of rFIXFc was given to Hemophilia A and B, respectively. We evaluated clinical outcomes and inhibitors occurrence, determined by screening and titration using the Nijmegen technique. Results: A total of 15 patients were included in the LDP regimen. The mean age was 6.3 years (1.5 - 10). A significant reduction was noted in the annualized bleeding rate, from 7.53 to 1.33 (p = 0.0001); the annualized joint bleeding rate passed from 3.6 to 1.4 (p = 0.001) and the proportion of severe bleeding, from 86.1% to 16.7% (p = 0.0001). The Hemophilia Joint Health Score (HJHS) moved from 9.6 to 3.4 (p = 0.0001) and the Functional Independence Score in Hemophilia (FISH) improved from 25.8 to 30.9 (p = 0.0001). School absenteeism decreased from 7.33% to 2.59%. Adherence to prophylaxis was 89.5% versus 60%. Consumption was 580 IU/kg/year versus 1254.6 IU/kg/year before and after prophylaxis, respectively. Incidence of inhibitors was 23% (3 /13 HA). Conclusion: The LDP in Hemophilia improves the clinical outcome without a surplus risk of inhibitor development. Using extended half-life clotting factor concentrates (CFCs) is better for prophylaxis in resource-limited countries, as they allow better compliance in treatment.

Red blood cell alloantibodies in paediatric transfusion in sub-Saharan Africa: A new cohort and literature review.

Blood transfusion support predisposes transfused children to the risk of erythrocyte alloimmunization in Sub-Saharan Africa. A cohort of 100 children receiving one to five blood transfusions were recruited for screening and identification of irregular antibodies using gel filtration technique. The mean age was 8 years and the sex-ratio at 1.2. The retrieved pathologies were: major sickle cell anaemia (46%), severe malaria (20%), haemolytic anaemia (4%), severe acute malnutrition (6%), acute gastroenteritis (5%), chronic infectious syndrome (12%) and congenital heart disease (7%). The children presented with haemoglobin levels ≤6 g/dl, and 16% of them presented positive irregular antibodies directed against the Rhesus (30.76%) and Kell (69.24%) blood group systems. A literature review shows that irregular antibody screenings vary from 17% to 30% of transfused paediatric patients in Sub-Saharan Africa. These alloantibodies are in particular directed against the Rhesus, Kell, Duffy, Kidd and MNS blood group and generally found in sickle cell disease and malaria. This study highlights the urgent need of extended red blood cell phenotyping including typing for C/c, E/e, K/k, and Fya/Fyb, and if possible Jka/Jkb, M/N, and S/s for children before transfusion in Sub-Saharan Africa.

Clinical outcome and incidence of inhibitor development in severe hemophilia patients receiving low-dose prophylaxis: a 3-year follow-up study in Senegal, West Africa.

INTRODUCTION: In Africa, where access to diagnosis and treatment of hemophilia is the lowest in the world, prophylaxis is rarely used in preference to on-demand treatment. There are limited data of prophylaxis treatment from sub-Saharan Africa. The aim of this study was to evaluate clinical outcomes and inhibitor development in people with hemophilia receiving low-dose prophylaxis (LDP) in a sub-Saharan African setting. METHODS: We conducted a three-year prospective study. A once or twice weekly prophylaxis regimen of 25 IU/kg of rFVIIIFc or 30 IU/kg of rFIXFc was given to Hemophilia A and B, respectively. We evaluated clinical outcomes and inhibitors occurrence, determined by screening and titration using the Nijmegen technique. RESULTS: A total of 15 patients were included in the LDP regimen. The mean age was 6.3 years (1.5 - 10). A significant reduction was noted in the annualized bleeding rate, from 7.53 to 1.33 (p = 0.0001); the annualized joint bleeding rate passed from 3.6 to 1.4 (p = 0.001) and the proportion of severe bleeding, from 86.1% to 16.7% (p = 0.0001). The Hemophilia Joint Health Score (HJHS) moved from 9.6 to 3.4 (p = 0.0001) and the Functional Independence Score in Hemophilia (FISH) improved from 25.8 to 30.9 (p = 0.0001). School absenteeism decreased from 7.33% to 2.59%. Adherence to prophylaxis was 89.5% versus 60%. Consumption was 580 IU/kg/year versus 1254.6 IU/kg/year before and after prophylaxis, respectively. Incidence of inhibitors was 23% (3 /13 HA). CONCLUSION: The LDP in Hemophilia improves the clinical outcome without a surplus risk of inhibitor development. Using extended half-life clotting factor concentrates (CFCs) is better for prophylaxis in resource-limited countries, as they allow better compliance in treatment.

Transfusion Practice, Post-Transfusion Complications and Risk Factors in Sickle Cell Disease in Senegal, West Africa.

CONTEXT AND OBJECTIVES: Blood transfusions (BT) remain a mainstay of therapy for patients with sickle cell disease (SCD) but pose significant clinical challenges. We aim to assess infectious markers, red cell alloimmunization, and iron overload secondary to BT in SCD patients. MATERIALS AND METHODS: This case-control study included 253 SCD (153 SCD-transfused and 100 SCD non-transfused). We evaluated the transfusion practice (modalities, indications), post-transfusion complications (infections, alloimmunization, iron overload), and risk factors of these complications (socio-demographic, clinical, biological). RESULTS: Median age was 28.5 years (5 - 59). The sex ratio was 0.86. Homozygous SCD was the most common (95.3%). Simple BT was performed in 92.8% and transfusion exchange in 18.9%. Transfusion indications were dominated by acute anemia (57.06%) and vaso-occlusive crisis (VOCs) (14%). Red blood cell concentrates (RBCSs) were administered to 93.46%. The median RBCs received per patient was 10 (2 - 48). The prevalence of VHC in SCD-transfused was 1.33% and 2% for VHB. Anti-HIV antibodies were not found. Red cell alloimmunization frequency was 16%. The most common alloantibodies were anti-rhesus (34.19%) and anti-Kell (23.67%). Iron overload was detected in 7.84%. The number of RBCs transfused was the only risk factor for alloimmunization (p = 0.03) and iron overload (p = 0.023). BT frequency was not related to infectious transmission. CONCLUSION: BT therapy is still a risk for SCD polytransfused patients despite advances in blood safety. Although infectious transmission has rare, the risk of alloimmunization and iron overload is high in these patients.