Transfusion therapy remains a key component of the treatment of sickle cell disease. Given that blood groups vary depending on an individual’s geographic origin, transfusion therapy can run into compatibility issues. In fact, in mainland France, nearly 95% of donors are of European descent, while the vast majority of patients are of African-Caribbean descent. Red blood cell incompatibilities can trigger a cascade of reactions in the recipient, which in some cases can be life-threatening. The French Blood Establishment works at every stage of the transfusion chain to optimize patient transfusions, from collection through the delivery of blood products to post-transfusion follow-up. Promoting blood donation among populations of the same geographic origin as the patients is a key element in optimizing transfusion care. (R.A.)