Antibody development in pediatric sickle cell patients undergoing erythrocytapheresis.

Background: Erythrocytapheresis, or red blood cell exchange transfusion (RBCX), with donor red blood cell (RBC) units is now increasingly used in the treatment of acute and chronic complications of sickle cell disease (SCD). As in all transfusions, RCBX carries a risk of immunization against foreign antigen on transfused cells. However, by selecting donor units with RBC phenotypes similar to the patient, the risk of allo- and autoimmunization can be reduced.

Methods: The formation of RBC alloantibodies and/or autoantibodies in 32 multitransfused pediatric SCD patients undergoing monthly RBCX over a 11-year period (12/1998 to 12/2009) was evaluated utilizing a retrospective patient chart review at Kosair Children's Hospital, Louisville, Kentucky.

Results: After starting C, E, K antigen-matched RBCX, the rate of clinically significant allo-immunization decreased from 0.189/100 to 0.053/100 U, with a relative risk of 27.9%. Likewise, the rate of autoimmunization decreased from 0.063/100 to 0.035/100 U, with a relative risk of 55.9%.

Conclusions: After controlling for clinically insignificant antibodies, our auto- and alloimmunization rate was much less than previously reported values. In addition, the incidence of clinically significant allo- and autoimmunization decreased in our patient population after starting minor antigen-matched RBCX. These results suggest that by matching selected RBC phenotypes, there may be an association in the risk of allo- and autoimmunization of multi-transfused SCD patients.