Increased Prevalence of Alloimmunization in Sickle Cell Disease? Should We Restore Blood Donation in French Guiana?

Prevalence of red blood cell alloantibodies in pregnant women with sickle cell disease in Bamako

BACKGROUND AND OBJECTIVES

Pregnancy in women with sickle cell disease (SCD) is associated with severe complications. Red blood cell (RBC) alloimmunisation is a worrying situation in pregnant women with SCD. This could increase the difficulty in finding a pheno-compatible red blood product. Our study aimed to determine the prevalence of RBC alloantibodies in pregnant women with SCD and to determine the risk factors for alloantibodies formation.

METHODS/MATERIALS

We conducted a prospective study at the "Centre National de Transfusion Sanguine de Bamako" from August 2022 to January 2023. For each participant, we collected important information, including obstetrical and transfusion histories. We performed ABO group, Rh and Kell phenotyping, and antibody screening in all study participants. We performed statistical analysis.

RESULTS

We recruited 95 pregnant women with SCD. In our study, 62% of our participant had a history of blood transfusion. Only 23% of our pregnant women with SCD had a history of miscarriage. The prevalence of RBC alloantibodies was 14%. The main antibodies detected were anti-E (38%) and pan-agglutinins (23%). Miscarriage history, blood transfusion history, and pregnancy number were the main risk factors for RBC alloimmunisation.

CONCLUSION

The care of pregnant women with SCD is complex and requires collaboration between haematologists, clinicians and gynaecologists. National guidelines should be implemented to make ABO and D typing, Rh and Kell phenotyping and antibody screening routine for all pregnant women. This would facilitate early detection of high-risk situations. Particular attention should be paid to SCD pregnant women with miscarriage and blood transfusion histories.

Jk(a) (Kidd-A) Variant in a Sickle Cell Disease Patient

Sickle cell disease (SCD) is a chronic and prevalent hemoglobin disorder with various manifestations and complications depending on the organs involved. Red cell transfusion either simple or exchange is crucial due to its prophylactic and therapeutic roles. We present a case showing serologic discrepancy between the red cells phenotype and the developed alloantibodies to emphasize the crucial role of molecular testing in SCD patients requiring chronic blood transfusion.

A Review of the Relationship between the Immune Response, Inflammation, Oxidative Stress, and the Pathogenesis of Sickle Cell Anaemia

Sickle cell anaemia (SCD) is a life-threatening haematological disorder which is predominant in sub-Saharan Africa and is triggered by a genetic mutation of the β-chain haemoglobin gene resulting in the substitution of glutamic acid with valine. This mutation leads to the production of an abnormal haemoglobin molecule called haemoglobin S (HbS). When deoxygenated, haemoglobin S (HbS) polymerises and results in a sickle-shaped red blood cell which is rigid and has a significantly shortened life span. Various reports have shown a strong link between oxidative stress, inflammation, the immune response, and the pathogenesis of sickle cell disease. The consequence of these processes leads to the development of vasculopathy (disease of the blood vessels) and several other complications. The role of the immune system, particularly the innate immune system, in the pathogenesis of SCD has become increasingly clear in recent years of research; however, little is known about the roles of the adaptive immune system in this disease. This review examines the interaction between the immune system, inflammation, oxidative stress, blood transfusion, and their effects on the pathogenesis of sickle cell anaemia.

Transfusional Approach in Multi-Ethnic Sickle Cell Patients: Real-World Practice Data From a Multicenter Survey in Italy

Sickle cell disease (SCD) is a worldwide distributed hereditary red cell disorder characterized by recurrent acute vaso-occlusive crises (VOCs and anemia). Gold standard treatments are hydroxycarbamide (HC) and/or different red blood cell (RBC) transfusion regimens to limit disease progression. Here, we report a retrospective study on 1,579 SCD patients (median age 23 years; 802 males/777 females), referring to 34 comprehensive Italian centers for hemoglobinopathies. Although we observed a similar proportion of Caucasian (47.9%) and African (48.7%) patients, Italian SCD patients clustered into two distinct overall groups: children of African descent and adults of Caucasian descent. We found a subset of SCD patients requiring more intensive therapy with a combination of HC plus chronic transfusion regimen, due to partial failure of HC treatment alone in preventing or reducing sickle cell-related acute manifestations. Notably, we observed a higher use of acute transfusion approaches for SCD patients of African descent when compared to Caucasian subjects. This might be related to (i) age of starting HC treatment; (ii) patients' low social status; (iii) patients' limited access to family practitioners; or (iv) discrimination. In our cohort, alloimmunization was documented in 135 patients (8.5%) and was more common in Caucasians (10.3%) than in Africans (6.6%). Alloimmunization was similar in male and female and more frequent in adults than in children. Our study reinforces the importance of donor-recipient exact matching for ABO, Rhesus, and Kell antigen systems for RBC compatibility as a winning strategy to avoid or limit alloimmunization events that negatively impact the clinical management of SCD-related severe complications.