Introduction Donor leucocyte antibodies have been associated with transfusion-related acute lung injury (TRALI) and can be present in allo-exposed donors. Donor deferral policies aiming at excluding allo-exposed donors are increasingly implemented worldwide. We aimed at assessing the prevalence of leucocyte antibodies in different subgroups of allo-exposed donors in the Dutch donor population. Methods Consecutive donors were enrolled during routine whole blood donation. Donors filled out a questionnaire on allo-exposure history. Blood samples were tested for human leucocyte antigens (HLA) (LifeScreen Deluxe and the Lifecodes LSA I/II assays) and granulocyte-reactive (GIFT, GAT, and MAIGA) antibodies. Results Six thousand and thirty-four consecutive donors (60% men) were included. A total of 2·5% reported a history of blood transfusions, and 51% (of female donors) reported a history of pregnancy. In never allo-exposed donors, the prevalence of granulocyte-reactive antibodies was 2·0% (95% CI: 1·6–2·4), and for HLA antibodies, it was 7·0% (95% CI: 6·3–7·8). In previously pregnant donors, the prevalence of granulocyte-reactive antibodies was increased to 3·0% (95% CI: 2·0–4·0), and for HLA antibodies, it was increased to 33% (95% CI: 30–36). Prevalence of leucocyte antibodies of all types depended on transfusion history, number of pregnancies, time since last pregnancy, and pregnancy outcome. Conclusions Fourteen percent of Dutch blood donors are allo-immunized against HLA or granulocyte antigens. Deferral of all self-reported allo-exposed donors will decrease this prevalence to 9%. Deferral of all female donors and transfused male donors will result in a similar prevalence among remaining donors but approximately twice as many deferrals.
