DIII Type 7 is likely the original serologically defined DIIIb

Abstract

Background Due to their homology, close proximity and opposite orientation, RHD and RHCE can exchange nucleotides giving rise to variant alleles. Some of these variants encode the so-called partial phenotypes. The DIII partial D category has been subdivided into DIIIa, DIIIb, DIIIc, DIII type 4, DIII type 6, and DIII type 7. During DNA-based screening tests, we identified a second example of DIII type 7 in a Dce donor from South Africa. Our study describes hemagglutination tests on this sample and raises a question regarding the molecular basis of the originally defined DIIIb category. Materials and methods Hemagglutination and DNA testing were performed by standard techniques. Results RBCs from this DIII type 7 donor typed D+C−E−c+e+G−, DAK+ and did not react with anti-D made by people with the DIII phenotype. The allele is RHD*DIII 150C, 178C, 201A, 203A, 307C, 410T, 455C, 602G, 667G). Conclusions Based on the serotype and ethnicity (black African), it is likely that DIII type 7 is the originally defined DIIIb category.

Rh and RHAG Blood Group Systems

“…Genes for DVI -2, -3, and -4, which are linked to RHCE * Ce , have exons 4 -6, 3 -6, and 3 -5, respectively, derived from RHCE * e (Ala226) [173 -175,177] . Apart from the polymorphism at residue 226, all three types have the same amino acid changes from normal D in predicted extracellular loops Asn152Thr, Thr201Arg, and Phe223Val [163,164] . Apart from the polymorphism at residue 226, all three types have the same amino acid changes from normal D in predicted extracellular loops Asn152Thr, Thr201Arg, and Phe223Val [163,164] .…”

“…Since then, numerous other partial D antigens have been identifi ed (Table 5.5 [126] ), creating many subsplits of the original reaction patterns. Other factors, such as with the DIIIb (DIII -7) and DOL variants and with the R N phenotype (Section 5.14.1.1 ) [160,164] . It includes 30 epitopes, with a terminology consisting of the original epD1 to epD9 (excluding epD7) [206,207,209] , followed by numbers representing subdivisions of the epitopes (e.g.…”