Transfusion in hemoglobinopathies and red blood cell alloimmunization: data from Sicily, Sardinia and Malta

Hemoglobinopathies are a group of diseases that include those due to globin gene mutations, such as thalassemia major (TM) and thalassemia intermedia (TI) or due to alteration of hemoglobin structure such as sickle cell disease (SCD), as well as a combination of these conditions such as thalasso-drepanocytosis (TD). They constitute the most frequent hereditary anemias requiring blood transfusion.

In April 2022, a questionnaire was sent to the Transfusion Services (TS) of Sicily, Sardinia and the Maltese National Blood Transfusion (MNBT) service. The questionnaire was divided into a generic part including the number of patients followed and the type of hemoglobinopathy, and a section relating to transfusion therapy, including the number of units transfused, whether red blood cells (RBC) were washed and, finally, a section relating to the presence or absence of alloantibodies and their identification.

Data was retrieved for 2,574 patients: 68.6% TM, 15.4% TI, 10.3% TD, 4.1% SCD, and 1.6% other hemoglobinopathies (OHA). The number of RBC units transfused was 76,974, equivalent to 24.5% of all the RBCU transfused from the total number of patients followed. The number of washed RBCU was 21.1% of all the units used; 337 patients (37%) were diagnosed with alloantibodies, the majority of which were patients with SCD (20.6%). Of the 485 alloantibodies found, 90.3% were identified. The antibodies found most frequently were related to the Kell system (41.7%) followed by antibodies to the Rhesus system (37.9%); 29.7% of patients had more than one antibody.

From our study, certain indications can be formulated: complete the National Registry for patients with hemoglobinopathies; create a Registry of alloimmunized patients to ensure transfusion therapy is as safe as possible, considering antibody evanescence; and 3) increase the recruitment of blood donors of diverse ethnicities.