ABO Incompatibility between the Mother and Fetus Does Not Protect against Anti-Human Platelet Antigen-1a Immunization by Pregnancy

• Published in: Journal of clinical medicine Vol. 11; no. 22; p. 6811
• Main Authors: Miserre, Laila, Wienzek-Lischka, Sandra, Mann, Andreas, Cooper, Nina, Santoso, Sentot, Ehrhardt, Harald, Sachs, Ulrich J, Bein, Gregor
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 17.11.2022; MDPI
• Subjects: ABO blood group; anti-human platelet antigen-1a; Antibodies; Antigens; Birth weight; Blood & organ donations; Blood groups; Blood platelets; Chi-square test; Clinical medicine; fetal and neonatal alloimmune thrombocytopenia; Fetuses; Genotype & phenotype; Hematology; Hypotheses; Immunization; Laboratories; Mothers; Pregnancy; Software; Thrombocytopenia; United States > US; Japan; fetal and neonatal alloimmune thrombocytopenia; ABO blood group; anti-human platelet antigen-1a
• ISSN: 2077-0383; 2077-0383
• DOI: 10.3390/jcm11226811

(1) Background: ABO blood group incompatibility between the mother and fetus protects against anti-D immunization by pregnancy. The possible role of ABO incompatibility in protecting against anti-human platelet antigen-1a immunization is unclear. (2) Methods: This study retrospectively screened 817 families (mother-father-neonate trios) of suspected fetal and neonatal alloimmune thrombocytopenia for inclusion. ABO genotypes were determined in 118 mother-child pairs with confirmed alloimmune thrombocytopenia due to anti-HPA-1a antibodies, and 522 mother-child pairs served as the control group. The expression of blood group antigen A on platelets was determined in 199 consecutive newborns by flow cytometry and compared with adult controls. (3) Results: ABO incompatibility between mother and fetus did not protect against anti-human platelet antigen-1a immunization by pregnancy. ABO blood groups of mothers and/or fetuses were not associated with the severity of fetal and neonatal alloimmune thrombocytopenia. The expression pattern of blood group A antigens on the platelets of newborns mirrored that of adults, albeit on a lower level. Blood group A antigen was detected on a subpopulation of neonatal platelets, and some newborns revealed high platelet expression of A determinants on all platelets (type II high-expressers). (4) Conclusion: The lack of a protective effect of ABO incompatibility between mother and fetus against anti-human platelet antigen-1a immunization by pregnancy may indicate that fetal platelets are not the cellular source by which the mother is immunized.