Acute non‐hemolytic transfusion reactions and HLA class I antibody: advantages of solid phase assay compared with conventional complement‐dependent assay

To evaluate the specific reactivity of HLA Class I antibodies (HLA‐I Abs) in acute non‐hemolytic transfusion reactions (ANHTRs) using solid phase assays (SPAs) and conventional complement‐dependent lymphocyte cytotoxicity test (LCT). ANHTRs are major issues in transfusion medicine. Anti‐leukocyte antibodies have been implicated as one of the causative agents of transfusion‐related acute lung injury (TRALI) and febrile reaction. Antibodies to HLA Class I and/or Class II (HLA Abs) have been intensively studied using SPAs for TRALI, but not for febrile reaction. About 107 patients and 186 donors associated with ANHTRs were screened for HLA Abs by SPAs such as enzyme‐linked immunosorbent assay (ELISA) and the Luminex method. When HLA‐I Ab was detected, its specific reactivity was evaluated by comparing its specificity identified by the Luminex method using recombinant HLA molecules and cognate HLA antigens (Ags), as well as LCT with or without anti‐human globulin (AHG). The incidences of HLA Abs were as high as 32·7% of patients' serum samples and 16% of donors' serum samples. The incidence of HLA‐I Abs did not differ significantly between cases of febrile and allergic reactions. However, HLA‐I Abs associated with febrile reaction showed a significantly higher rate of possessing specific reactivity to cognate HLA Ags than those associated with allergic reactions. In addition, the Luminex method enabled the detection of HLA‐I Abs much earlier than AHG‐LCT in serum samples from a patient with febrile reaction and platelet transfusion refractoriness (PTR). SPAs seem more useful than AHG‐LCT for evaluating reactivity of antibodies in ANHTR cases.