Identification of anti-PP1Pk in a blood donor and her family: A case report following her pregnancy and review

Anti-PP1Pk is a rare, biphasic antibody with the ability to cause immediate hemolytic transfusion reactions and early spontaneous abortions. The antibody is formed by individuals with the p phenotype. A blood donor with anti-PP1Pk and the p phenotype was identified through routine donor screening. A sister was found to also be p phenotype. At that time, the sister was 24 weeks pregnant. Subsequently, the original blood donor became pregnant. Both individuals were followed throughout their pregnancies and delivered infants without complications from anti-PP1Pk antibodies. The literature regarding anti-PP1Pk, the p phenotype, and recurrent pregnancy loss in this setting is reviewed.