Anti-LW masquerading as anti-D in a D+ patient

Area of Science:

• Hematology
• Immunology
• Transfusion Medicine

Background:

• The Landsteiner-Weiner (LW) blood group system comprises four main antigens: LWa, LWab, LWb, and LWEM.
• LW antigen expression can decrease during pregnancy or immune dysregulation, potentially leading to anti-LW antibody formation.

Purpose of the Study:

• To describe a challenging case of red blood cell (RBC) transfusion in an elderly male with anti-LW antibodies.
• To investigate the cause of anti-LW antibody development in the context of an underlying hematologic disorder.

Main Methods:

• Serologic workup including antibody screening and reactivity testing with various red blood cell phenotypes.
• Dithiothreitol treatment of red blood cells to differentiate antibody specificities.
• Genotyping of the LW blood group system.
• Bone marrow examination to diagnose underlying disorder.

Main Results:

• The patient presented with anti-LW antibodies, causing incompatibility with standard RBC transfusions.
• Antibody screening revealed specific reactivity patterns, including abolition with dithiothreitol-treated cells.
• Patient genotyping confirmed LW*A/A (c.299A), indicating an LWa+b- phenotype.
• A B-lymphoproliferative disorder was diagnosed.
• Transfusion with specific A, D- RBC units was successful and uneventful.

Conclusions:

• Weakened LW expression, potentially due to the underlying B-lymphoproliferative disorder, likely led to the development of anti-LW antibodies in this patient.
• Careful selection of compatible RBC units, specifically A, D- units, enabled successful transfusion support.
• This case highlights the importance of thorough antibody investigation in patients with transfusion difficulties.