Alloanti-D induction in a rare RhD variant (DBT-2) case: Insights from serological and molecular biological testing

The RhD antigen is the most immunogenic within the Rh blood group system， playing a pivotal role in clinic. The D variant phenotype is a rare occurrence, characterized by low expression of the D antigen or partial deletion of the RhD antigen on the surface of red blood cells (RBCs). For individuals with the D variant, transfusion with RhD-negative blood is crucial for ensuring transfusion safety.

We present a case of a 63-year-old Han Chinese female, identified as a D variant phenotype without a history of blood transfusion but with a history of pregnancy. Pre-transfusion testing revealed the presence of alloanti-D antibodies. Genetic analysis confirmed the patient's genotype as RHD-CE (5-9)-D, and her phenotype was classified as DBT-2.

This report marks the first case in China of anti-D alloimmunization in patients with the D variant. Both serological and molecular detection of the D variant are essential to ensure the safety of blood transfusions.