Genomewide association study of HLA alloimmunization in previously pregnant blood donors

BACKGROUND Alloimmunization through blood transfusion, transplantation, or circulating fetal cells during pregnancy is a significant concern. Some exposed individuals make alloantibodies while others do not, implying variation in genetic risk factors. STUDY DESIGN AND METHODS We conducted a genomewide association study (GWAS) of 9,427,497 single‐nucleotide polymorphisms (SNPs) to identify genetic variants for HLA alloimmunization in previously pregnant blood donors with (n = 752) and without (n = 753) HLA Class I or II alloantibodies. RESULTS A SNP in the neurexophilin 2 (NXPH2) gene surpassed genome‐wide significance (p = 2.06 × 10−8), with multiple adjacent markers p