Red blood cell alloimmunization

Recipient immune system recognition of donor red blood cell antigens is the fundamental process underlying red blood cell (RBC) alloimmunization. This biological event occurs when the recipient's immune system, particularly antigen-presenting cells and B-lymphocytes, identifies foreign polymorphic proteins or carbohydrates on the surface of transfused or fetal RBCs (Zimring, 2015). The resulting immune response leads to the production of alloantibodies, which can mediate the destruction of donor cells, causing hemolytic transfusion reactions or hemolytic disease of the fetus and newborn (HDFN) (Tormey & Hendrickson, 2019). Therapeutic management involves prophylactic measures like Rho(D) immune globulin to prevent sensitization by masking antigens or clearing donor cells (StatPearls). Emerging therapies such as FcRn inhibitors (e.g., nipocalimab) target the neonatal Fc receptor to reduce the levels of circulating pathogenic IgG, thereby protecting the fetus in HDFN (Lingampalli et al., 2020). Understanding this recognition pathway is critical for improving transfusion safety and managing maternal-fetal blood group incompatibilities. Additionally, B-cell and plasma cell depleting agents like rituximab and daratumumab are sometimes used in refractory cases to suppress the production of these alloantibodies (Zimring, 2015).

Other names

Recipient immune system recognition of donor red blood cell antigensRBC alloimmunizationErythrocyte alloimmunizationAlloimmune hemolytic anemiaHemolytic disease of the fetus and newborn pathwayTransfusion-induced alloimmunization

Therapeutic strategies involve masking donor antigens to prevent recognition (e.g., Rho(D) immune globulin), depleting B-cells or plasma cells to stop antibody production (e.g., Rituximab, Daratumumab), or blocking the neonatal Fc receptor (FcRn) to accelerate the clearance of pathogenic IgG antibodies (e.g., Nipocalimab).