Primary anti-D immunization by DEL red blood cells

Area of Science:

• Transfusion Medicine
• Immunology
• Genetics

Background:

• The DEL phenotype, characterized by extremely weak D variants of the RHD gene, is typically detected using adsorption-elution techniques.
• The RHD (K409K, 1227G>A) allelic variant is prevalent in East Asian DEL individuals.
• Previously, no DEL phenotype had been documented to induce primary alloanti-D immunization in East Asia.

Observation:

• A 68-year-old D-negative Korean man developed alloanti-D antibodies after receiving red blood cell (RBC) transfusions from four apparently D-negative donors.
• Routine serological testing identified the donors as D-negative.
• Molecular analysis revealed one donor carried the RHD (K409K) variant.

Findings:

• This case represents the first documented instance of DEL red blood cells with the RHD (K409K) variant inducing primary alloanti-D immunization in an Asian population.
• The DEL phenotype, previously considered non-immunogenic in this population, demonstrated immunogenic potential.

Implications:

• The findings necessitate a re-evaluation of transfusion protocols, particularly concerning RhD-negative donor screening in populations with a high prevalence of DEL variants.
• Molecular methods for detecting RHD gene carriers, such as the RHD (K409K) variant, should be considered for efficient screening.
• This underscores the importance of advanced genotyping for ensuring transfusion safety and preventing alloimmunization, especially in diverse ethnic groups.