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ABO incompatibility and RhIG immunoprophylaxis protect against non‐D alloimmunization by pregnancy
Author(s) -
Zwiers Carolien,
Koelewijn Joke M.,
Vermij Lisa,
van Sambeeck Joost,
Oepkes Dick,
de Haas Masja,
van der Schoot C. Ellen
Publication year - 2018
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/trf.14606
Subject(s) - abo blood group system , medicine , pregnancy , obstetrics , abo incompatibility , immunization , population , antibody , fetus , haemolytic disease , gynecology , immunology , biology , genetics , environmental health
BACKGROUND Hemolytic disease of the fetus and newborn (HDFN) is caused by maternal antibodies against fetal red blood cell antigens, most often anti‐D, ‐K, or ‐c. ABO incompatibility between mother and child and anti‐D immunoprophylaxis (RhIG) are known to reduce the risk of D immunization and subsequent HDFN. However, no immunoprophylaxis has been developed to prevent non‐D immunizations. STUDY DESIGN AND METHODS We evaluated whether ABO incompatibility has a preventive effect on formation of non‐D alloantibodies, by performing a case‐control study including pregnant women with newly detected non‐D antibodies, identified within a nationwide data set, immunized during their first pregnancy and/or delivery. Subsequently, we assessed a possible protective effect of RhIG in a subgroup with non‐Rh antibodies only. The proportions of previous ABO incompatibility and of RhIG administrations of these women were compared to the known rate of 19.4% ABO incompatibility and 9.9% RhIG administrations (D– women carrying a D+ child) in the general population of pregnant women. RESULTS A total of 11.9% of the 232 included immunized women had a possible ABO incompatibility in their first pregnancy (vs. expected 19.4%; 95% confidence interval [CI], 7.3‐18.8; p = 0.036). Furthermore, 1.0% women with non‐Rh antibodies were D–, delivered a D+ child, and had therefore received RhIG, whereas 9.9% was expected (95% CI, 0.18‐5.50; p = 0.003). CONCLUSION We found that ABO incompatibility and RhIG reduce the risks not only for D, but also for non‐Rh immunizations, suggesting that antibody‐mediated immune suppression in this condition is not antigen specific.