A comparison of two robotic platforms to screen plateletpheresis donors for HLA antibodies as part of a transfusion-related acute lung injury mitigation strategy

BACKGROUND: Efforts to minimize white blood cell alloantibodies, responsible for transfusion-related acute lung injury (TRALI) in components with high-volume single-donor plasma include consideration of plateletpheresis donor screening for human leukocyte antigen (HLA) antibodies. High-throughput screening platforms make this feasible for large blood centers. Which platform to use, donor subgroups to screen, characteristics of detected antibodies, and operational impact of deferring reactive donors are important questions. STUDY DESIGN AND METHODS: We screened 2462 plateletpheresis donor sera for HLA antibodies on automated instruments using HLA Class I and II enzyme-linked immunosorbent assays (ELISA) or a mixed Class I/II Luminex flow analyzer. Screen-reactive samples were further tested by manual Luminex single-antigen assay to determine antibody specificity, estimated corresponding antigen frequency, and signal strength. RESULTS: Alloexposed females had the highest reactivity rate on both platforms (21.0%), with much lower rates for nonexposed individuals or transfused males (1.4%-5.4%). Increasing parity and more recent pregnancy increased their likelihood of screen reactivity. Deferring screen-reactive parous females would result in at least a 4.8% plateletpheresis donor base decrement. Supplemental testing showed higher rates of nonspecific or natural antibodies in ELISA screen-reactive alloexposed females (2.5%) than Luminex (0%). Both assays were more likely to identify antibodies directed against a larger number of HLA antigens and/or of presumed higher titer in alloexposed donors. CONCLUSION: A strategy screening only parous female donors is reasonable. Both automated HLA antibody detection platforms are easy to use and preferentially identify alloexposed individuals with antibodies of presumed higher titer directed against more recipient HLA antigens.