Assessing RBC transfusion efficacy in chronic transfusion recipients: advancing precision transfusion medicine

Abstract

PREVIEW

In this issue of Blood Transfusion, Karafin et al.¹ describe a study protocol to measure transfusion outcomes in chronic transfusion recipients in the US and Brazil. This observational trial includes patients with thalassemia and sickle cell disease (SCD), and children with hematology-oncology diagnoses. A range of hemoglobin (Hb) measures and markers of iron metabolism, hemolysis, and inflammation were measured before and after sequential transfusions in recipients. In addition, transfusion-focused genotyping was performed on blood donors and recipients, and donor/donation data were linked to the recipient outcomes.
Defining transfusion effectiveness has proved to be a challenging task across multiple patient populations. In acute illness or hemorrhage, important parameters include hemoglobin increment (easy to measure) and 24-hour post-transfusion recovery, i.e. RBC survival, and brain and tissue oxygenation (more difficult to measure). Furthermore, these measures are all proxy measures, since what we as clinicians care about is patient survival and prevention of morbidity. Even randomized clinical trials measuring parameters such as the Hb threshold for transfusion can be difficult to interpret due to heterogeneity of transfusion recipient populations². Chronically transfused patients offer a population with known complications from repeated transfusion. While RBC transfusion has largely prevented childhood mortality from β-thalassemia major, RBC alloimmunization and iron overload remain significant causes of morbidity in these patients³. Similarly, chronic RBC transfusion has been shown to prevent stroke in children with SCD at high risk⁴, though again RBC alloimmunization and iron overload remain concerns in this population. [ ... ]