Background: After initial alloimmunization, 20 to 25 percent of immunized nonhematooncology patients develop additional red blood cell (RBC) antibodies after subsequent transfusions. This figure is unknown for hematooncology patients.
Study design and methods: A 24-year retrospective study was conducted to determine whether RBC-immunized hematooncology patients differ from other patient cohorts regarding this strong immune response toward additional RBC challenge with clinically relevant RH, KEL, FY, JK, and MNS antigens.
Results: Overall, 25 of 115 immunized patients (21.7%) formed 30 additional antibodies after a median number of 7 RBC units transfused. The median interval between primary and additional antibody detection was 4 months. Diagnosis or treatment intensity did not significantly influence additional antibody development.
Conclusion: Additional antibody formation occurs in more than 20 percent of RBC-alloimmunized hematooncology patients after subsequent transfusions and this is comparable with the frequency in other immunized patients. To avoid extensive RBC alloimmunization, preventive extended antigen matching may be considered in hematooncology patients, who have shown to be capable of antibody formation.