A study published in the journal Blood suggests that low to moderate levels of human leukocyte antigen (HLA) antibodies are not predictive of platelet transfusion failure. Among 530 participants from the Trial to Reduce Alloimmunization to Platelets (TRAP) study, 101 had developed plateletrefractoriness without evidence of HLA or human platelet antigen (HPA) antibodies, as detected by a lymphocytoxicity assay (LCA). Researchers further evaluated HLA antibody levels among a subset of TRAP participants using longitudinal panel analysis with a more sensitive bead-based assay. Among 170 LCA-negative participants evaluated, HLA antibody levels were not significantly higher among those with clinical refractoriness than those without refractoriness. However, among 20 LCA-positive individuals, higher levels of HLA antibodies were significantly associated with clinical refractoriness. Levels of HPA antibody, as measured by a sensitive enzyme-linked immunosorbet assay, were not predictive of clinical refractoriness, among LCA-negative and LCA-positive patients.
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