A case of high-titer anti-D hemolytic disease of the newborn in which late onset and mild course is associated with the D variant, RHD-CE(9)-D




The RhD antigen is very immunogenic and is a significant cause of hemolytic disease of the newborn (HDN). The RHD-CE(8-9)-D hybrid allele is commonly associated with a D– phenotype. Here, we report a case of high-titer maternal anti-D and late onset of HDN in a newborn carrying a RHD-CE(9)-D variant supposedly encoding the same partial D antigen as the RHD-CE(8-9)-D allele, but with significant expression of D antigen.

Study Design and Methods

To elucidate the blood group antigen background of the case, we carried out serologic, flow cytometric, and genetics studies of the newborn and his father.


Individuals carrying the RHD-CE(9)-D allele do express D antigen, but do so at significantly lower levels than those carrying the more common D+ phenotypes (e.g., DCe/dce). It may mitigate and delay otherwise severe HDN in pregnancies complicated by high-titer anti-D.