Red cell exchange does not appear to increase the rate of allo- and auto-immunization in chronically transfused children with sickle cell disease.

BACKGROUND: Allo- and auto-antibody development is a well recognized complication of chronic red cell transfusion (RCT) in sickle cell disease (SCD). Limited matching of Rh (C, c, D, E, e) and K red cell antigens reduces the incidence of immunization. PROCEDURE: We reviewed our experience with red cell allo- and auto-immunization in pediatric SCD patients receiving chronic and/or exchange transfusions, to evaluate the rate of immunization after limited red cell antigen matching and specifically during red cell exchange (RCE) transfusion. A retrospective chart review of the patients with SCD followed at our center between 2002 and 2006, who were started on chronic RCT before or during that time period, was conducted.
RESULTS: Of the 93 patients who met study criteria, 23 (24%) developed antibodies during chronic red cell transfusions. Thirty-four antibodies (15 auto-antibodies, 18 allo-antibodies) developed after the institution of limited red cell antigen matching. The rate of allo- and auto-immunization per unit of red cell exposure after limited phenotyping was 1.5%, comparable to other published data. Fifteen patients underwent RCE, utilizing a total of 2,289 packed red cell units. None developed antibodies during RCE.
CONCLUSION: We conclude that limited red cell antigen matching is an effective strategy for reducing the incidence of allo- and auto-immunization in chronically transfused children with SCD. RCE does not appear to increase the risk of allo- or auto-immunization, despite exposure to more red cell units.