Impact of HLA antigen and antibody expression on cross-matching and transfusion effect

[Objective] To study the relationship between the expression intensity of HLA-Ⅰ platelet antibodies in patients with platelet transfusion refractoriness (PTR) and platelet cross-matching, and to further evaluate other factors in order to provide relevant data support for improving platelet transfusion efficiency and optimizing platelet transfusion regimens. [Methods] Luminex single antigen flow cytometry was used to detect platelet specific antibodies in 35 patients with hematological disease. Subsequently, the Capture-P method was employed to perform 102 crossmatchings between plasma with HLA-Ⅰ antibodies and platelets with known HLA-Ⅰ genotypes. The cross-matching results were assessed and the clinical transfusion outcomes were tracked. [Results] The positive detection rate of HLA-Ⅰ and HPA antibodies in this study was 48.6% (17/35). The negative rate of cross-matching in 102 cases was 37.3% (38/102). Multiple factors affect platelet cross-matching, such as HLA-Ⅰ antibody expression level and antibody type, antigen expression level, cross-reactivity group and eplets. Among them, the expression level and antibody type of HLA-Ⅰ antibody are the main influencing factors. However, the effectiveness of clinical platelet transfusion is not completely determined by the compatibility of platelet cross-matching. [Conclusion] In addition to avoiding strong positive HLA-Ⅰ antibodies, clinical matching should also be vigilant against the serological cross-incompatibility caused by weak positive HLA-Ⅰ antibodies. It may be necessary to establish HLA-Ⅰ low expression antigen database as a better alternative platelet donor selection strategy, and gradually explore the effectiveness of ‘low expression mismatch’ strategy for clinical platelet transfusion.