Red blood cell alloimmunization in sickle cell disease and in thalassaemia: current status, future perspectives and potential role of molecular typing

Abstract

Red blood cell (RBC) transfusions are a milestone in the treatment for sickle cell anaemia (SSA) and for thalassaemia. RBC alloimmunization remains a major challenge of chronic transfusion therapy, and it can lead to adverse life-threatening events. The alloimmunization risk could depend on multiple factors such as the number of transfusions and, most of all, the genetic background. Different ethnic groups are predisposed to immunization because of a significant degree of RBC antigenic mismatch between donor and recipient. There is no universal agreement and standards for the most appropriate selection of RBC units in chronically transfused subjects. Current practice only deals with compatibility of ABO, Rh and K antigens. Molecular RBC antigenic matching extended to other blood group systems is an innovative strategy to ensure a better quality and effectiveness of transfusion therapy.

Lifetime risk and characterization of red blood cell alloimmunization in chronically transfused patients with sickle cell disease

“…One explanation could be the methodology in this study which includes lifetime risk of alloantibodies through records that date back to their childhood until date of data collection. Although data is limited on patients who are on red cell exchange, the prevalence is still within the range identified for patients with sickle cell disease which was reported to be anywhere between 2.6-60% [1].…”

“…Considering the cost and time needed to provide compatible units to alloimmunized patients with SCD who are on chronic red cell transfusion, the need for interventional studies aimed at understanding and preventing this complication is tremendous [1].…”

“…The risk of developing alloantibodies in patients with sickle cell disease is widely variable and estimated to range between 2.6-76% depending on the clinical characteristics of patients studied and the sensitivity of the tests used. Another estimate from a study showed 18-47% [1,2].…”

“…Such newly identified alloantibodies make subsequent transfusion difficult, costly and could also result in life-threatening acute and delayed hemolytic transfusion reactions [1]. The risk of developing alloantibodies in patients with sickle cell disease is widely variable and estimated to range between 2.6-76% depending on the clinical characteristics of patients studied and the sensitivity of the tests used.…”

Transfusion in Haemoglobinopathies: Review and recommendations for local blood banks and transfusion services in Oman

“…66 Molecular methods are particularly useful in patients with recent transfusions and no baseline phenotype as well as patients with autoantibodies and complex alloimmunisation. 67 Comparative studies show that alloimmunisation and delayed haemolytic transfusion reactions are less frequent in automated RBC exchange transfusions compared to chronic simple transfusions, despite increased blood exposure. [68][69][70] However, this finding may be due to the fact that some patients receive RBCs with a higher degree of phenotype-matching during automated exchange transfusions.…”