Causes of HLA-A2 reactive antibodies and analysis of their eplets / 中国输血杂志

ABSTRACT

【Objective】 To analyze differences of eplets between the patient who generated HLA allele-specific antibodies after platelet transfusion with donors. 【Methods】 The HLA genotypes of the patient and donors were detected by PCR-SBT, and the Luminex single antigen beads coating was used to screen HLA-Ⅰ antibodies in the patient’s serum. HLA Matchmaker was utilized to analyze different amino acids and eplets. 【Results】 The patient carried HLA-A*02∶03 allele, and HLA-A2 antibodies were found in his serum after platelet transfusion (A*02∶01, A*02∶06, and A*02∶07). Sequence alignment showed that the patient′s A*02∶03 has a difference in position 149, which resulted in a different eplet between A*02∶03 and A*02∶01, A*02∶06, A*02∶07 and then induced the production of antibodies. 【Conclusion】 HLA antibodies are specific for HLA epitopes that have structural differences due to amino acid differences between HLA alleles, suggesting that high-resolution typing of HLA-A, -B need to be conducted in patients and donors, and the acceptable mismatch of HLA should be determined based on epitopes rather than antigens, so as to reduce alloimmune response and improve platelet count after transfusion.