The prevalence of HPA‐1a alloimmunization and the potential risk of FNAIT depend on both the DRB3*01:01 allele and associated DR‐DQ haplotypes. - Ahlen, Maria Therese; Heide, Gøril; Husebekk, Anne; Skogen, Bjørn; Kjeldsen‐Kragh, Jens; Stuge, Tor B. (Scandinavian Journal of Immunology, 2020)