Sickle Cell Disease: Targeting Alloantibody formation Reduction; RIsk factors, aNd Genetics

The cornerstone in the treatment of sickle cell disease (SCD) patients are
blood transfusions. SCD patients receiving blood transfusions are at high risk
for alloimmunization, a complicating factor for future blood transfusions, as
these patients are at risk for serious complications such as delayed hemolytic
transfusion reactions. Moreover, it becomes more challenging to find compatible
blood for the patients, as these compatible units are scarce. Extended matching
reduces allo-antibody formation; however it is laborious and time-consuming.
Presently, only a few genetic and environmental risk factors have been
implicated. Inflammatory state at the time of transfusion is associated with
allo-antibody formation, which is of importance for SCD patients, as they
experience chronic inflammation as a result of chronic hemolysis. However, no
prospective studies have been conducted to elucidate allo-antibody formation in
the SCD population. Identification of SCD patients at high risk for
alloimmunization may help in developing tailored prevention strategies, such as
extended matching for patients at high risk for allo-antibody formation.

In this study, the genetic risk factors and time dependent risk factors for
alloimmunization will be analyzed. Furthermore, the role of the innate and
adaptive immune system on allo-antibody formation in SCD patients will be
elucidated.

This is a national, prospective multicenter observational cohort study.

Participants in this study will undergo a total of 5 blood sample drawings in 6
months. A total of 180 ml will be drawn from adults and children >=12 years and
110 ml from children <12 years. The blood sampling will be combined as much as
possible with regular outpatient department visits and regular blood control,
in order to reduce the burden and additional visits to the hospital. As this is
the only intervention, the risk of participating in this study for the patient
is negligible.