Complete D epitope expression of the most common weak D types 15, 25, 33, and 72 in the Chinese population

Abstract

Background - The most common weak D type 1, 2, and 3 individuals in the Caucasian population can be safely treated as D+ patients. However, the management of the common weak D type 15 in the East Asian population and the frequent weak D types 25, 33, and 72 in the Chinese population remains controversial.

Materials and methods - D epitope expression in individuals with weak D types 15, 25, 33, and 72 was assessed using an anti-D panel (D-Screen) via both hemagglutination and sensitive adsorption/elution methods. Furthermore, these four variant RHD constructs and one wild-type (wt) RHD construct were cotransfected with the wt RHAG construct into HEK 293T cells in vitro. After transfection, the surface expression of the RhD antigen was assessed via flow cytometry with a panel of monoclonal anti-Ds.

Results - Routine serological D epitope typing with D-Screen revealed that the red blood cells of weak D types 15 (No.=3), 25 (No.=3), 33 (No.=4), and 72 (No.=3) individuals were negatively agglutinated with one or multiple monoclonal anti-Ds. For the D epitopes undetectable by hemagglutination testing, positive reactions were obtained in the adsorption/elution tests when the corresponding non-reactive monoclonal anti-Ds were used. In vitro expression analyses revealed that all four weak D variant constructs expressed all tested D epitopes comparable to those observed with the wt RHD construct.

Discussion - The complete repertoire of D epitope expression was observed both in weak D types 15, 25, 33, and 72 individuals in vivo and expression analysis in vitro. This provided evidences that individuals with these four weak D types, similar to D+ patients, can receive D+ red blood cell transfusion and do not require Rh immunoglobulin prophylaxis.