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

Abstract

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.

Clinical trial registration: ClinicalTrials.gov, identifier: NCT03397017.

Keywords: alloimmunization; hydroxycarbamide; multi-ethnicity; sickle cell disease; transfusion therapy.

Figure 1

(A) Distribution of sickle cell disease (SCD) patients by age and ethnicity. Data are shown as a column chart that reports, for each age group, the number of Africans and Caucasians patients of the cohort. (B) Distribution of SCD patients by genotype and therapy. Data are shown as a column chart that reports, for each genotype, the number of patients that received HC/ATR/CTR/NONE as their therapy regimen. ATR, acute transfusion; CTR, chronic transfusion; HC, hydroxycarbamide.

Figure 2

(A) Distribution of sickle cell disease (SCD) patients by age and therapy. Data are shown as a column chart that reports, for each age group, the number of patients that received HC/ATR/CTR/NONE as their therapy regimen. (B) Distribution of the indications for transfusion therapy. Data are shown as counts of the indications for ATR and CTR. ACS, acute chest syndrome; ATR, acute transfusion; CTR, chronic transfusion; HC, hydroxycarbamide; MOFs, multi-organ failures; VOCs, vaso-occlusive events.

Figure 3

Number of children/adults in SCD patients by antibody system. The pie charts report the overall distribution of the specific antibodies for children and adults. Data are shown as column chart that reports, for each system and differentiating for children/adults, the number of African, Caucasian and African-American patients with the specific antibody.