Antibodies to human leukocyte antigens and eplet patterns associated with platelet transfusion refractoriness in Hispanic patients.

Antibodies to Class I human leukocyte antigens (HLAs) are a major immunologic cause of platelet transfusion refractoriness (PTR). HLA inheritance is highly related to ethnicity. Because most platelet donors are White, Hispanic patients may be at an increased risk of developing HLA antibodies due to mismatch between donor and recipient. This retrospective study analyzed 16 Hispanic patients with PTR to evaluate HLA antibodies associated with PTR. Baseline mean fluorescent intensity (MFI) was used to measure HLA antibody detection. Additive MFI values and clinical cut points were evaluated for Class I HLAs. Additionally, eplet exposition scores for antibody-verified eplets were totaled and compared with corrected count increment (CCI). Significant negative correlations were found between CCI with total additive MFI (r = -0.656) and allele-specific MFI for HLA A*03:01 (r = -0.728), C*14:02 (r = -0.795), and C*01:02 (r = -0.727). Analysis of cut points yielded significance between negative and strong MFI for HLA B*07:02. Data reveal that antibodies against common HLA alleles, such as A*03:01, correlate with PTR, highlighting the potential impact on alloimmunization and PTR risks in Hispanic patients.