RBC T activation and hemolysis in a neonatal intensive care population: implications for transfusion practice

Background: Reports of transfusion-associated hemolysis in infants with T-activated RBCs have led to the suggestion that infants should be screened and provided with low-titer anti-T blood components. T-activated RBCs react with the lectins Arachis hypogea and Glycine soja; variants of T (Th and Tx) and Tk also react with A. hypogea, but not G. soja. Although Tk is not a true variant of T, for the purposes of this study, all RBCs that are reactive with A. hypogea but are not reactive with G. soja are called "T variants." Study design and methods: A prospective study was carried out to examine T and T variant activation and transfusion-associated hemolysis in a neonatal intensive care population and to determine if antibodies to T and T variant are detectable in donor plasma. A total of 2041 samples from 375 infants were tested for T and T variant activation utilizing a lectin panel. Three hundred donor plasma samples were tested for antibodies to T and T variant. Results: Forty-eight of 375 infants (12.8%) had T- and T-variant-activated RBCs. Of these, 13 of 48 (27%) developed at least one episode of sepsis and 9 of 48 (19%) developed necrotizing enterocolitis (NEC) at some point during their inpatient stay. T activation was not always temporally associated with the onset of NEC or sepsis. The remaining 26 of 48 (54%) were healthy infants receiving convalescent care in the neonatal intensive care units and showed no evidence of either NEC or sepsis. Twelve (of 375) additional infants (3.2%) who developed NEC and 100 (27%) who developed sepsis showed no RBC T activation. Twenty-three of 48 (48%) infants with T-activated RBCs received standard blood components, but no transfusion-associated hemolysis occurred. Donor plasma samples contained T but not T variant antibodies. Conclusion: T variant activation of RBCs occurs in healthy neonates as well as in infants with NEC and sepsis, but T activation appears rare. Transfusion-associated hemolysis was not seen. The provision of specially prepared blood components for infants with NEC is unnecessary.