The main objectives of this study are to study the role of the innate and adaptive immune response in allo-antibody formation and furthermore to identify the genetic and time dependent clinical risk factors on alloimmunization in SCD patients.~Subjects without allo-antibodies, receiving a red blood cell transfusion, will be included in this study. At 5 time points blood will be drawn from these subjects. (T0: Before transfusion, T1: 1 day after transfusion, T2: 1 week after transfusion, T3: 4 weeks after transfusion, T4: 6 months after transfusion).~At each time point specific markers of the immune system will be measured.
The focus of the study is the pathophysiological mechanism of allo-antibody formation after red blood cell transfusion in sickle cell disease patients.