In blood banking, an alloantibody may be formed in response to pregnancy, transfusion, or transplantation. This alloantibody is targeted against a blood group antigen that is not present on the recipient’s red blood cells. This is a natural process as your body tries to defend itself from foreign substances. This process is called alloimmunization.
People living with sickle cell disease (SCD) have the highest prevalence of red blood cell (RBC) alloimmunization of any studied population. Up to 40–50% of transfused people with SCD form RBC alloantibodies over their lifetimes, compared to fewer than 5% of the “general” transfused population. Due to the frequency of needed transfusions, a SCD patient may develop multiple alloantibodies over the course of their life.
RBC alloantibodies may be clinically significant in transfusion and pregnancy situations, potentially leading to hemolytic reactions or hemolytic disease of the fetus and newborn. To avoid these types of reactions, transfused RBC units must be negative for the antigens that the alloantibodies will react with. Locating compatible RBC units for patients with SCD is often difficult and at times impossible.
When a SCD patient develops multiple antibodies, units for transfusion become much harder to locate. Some of the most common antigen combinations for SCD patients in our area are only found on <1% of random donor units. Several combinations we supply can only be found on 1 in 1000 random donors. There is a continuous need for these antigen-matched units in our area since several of these patients require transfusion of multiple units every month.