Alloimmunization in preterm infants after repeated transfusions of WBC-reduced RBCs from the same donor

BACKGROUND: Preterm infants are among the most heavily transfused of patien t groups, yet multiply transfused infants only rarely produce alloantibodie s against RBC or WBC antigens. It is not known whether rates of alloimmuniz ation might be increased by repeated exposure to RBCs and WBCs from the sam e donor, as in limited-donor-exposure programs, or whether infants might be nefit from WBC-reduced RBC components as a means of diminishing the risk of possible alloimmunization. STUDY DESIGN AND METHODS: Preterm infants (birth weight 0.6-1.3 kg) receive d prestorage WBC-reduced RBCs from dedicated donors, collected in AS-3 as a means of limiting donor exposures. Blood samples were collected serially f rom infants shortly after birth until either discharge or age 6 months and were studied for RBC and WBC antibodies-the latter with reactivity against either HLA class I or neutrophil-specific antigens. RESULTS: Thirty preterm infants received 139 transfusions (mean, 4.6; media n, 4 transfusions per infant), with 81 percent of transfusions obtained fro m one donor per infant. Eighty-four blood samples (mean, 2.7/infant) were s tudied, and no infant produced RBC antibodies. Twenty-seven percent of infa nts exhibited WBC antibodies, but only 13 percent actually produced WBC ant ibodies (passive maternal antibody excluded). Of the WBC antibodies produce d by infants, three were against HLA class I and one was against neutrophil -specific antigens; none were linked to adverse effects. CONCLUSIONS: Because infants only rarely produce RBC antibodies, no changes in blood banking practices are necessary for limited-donor-exposure progra ms. Although the production of WBC antibodies by infants occurs, it seems t o be uncommon; thus, the possible benefits, if any. of WBC reduction are un certain, and further study is required before changes in practice can be ju stified.