Red cell antigens as functional molecules and obstacles to transfusion

Area of Science:

• Hematology
• Immunology
• Transfusion Medicine

Background:

• Blood group antigens (BGAs) on red blood cells (RBCs) play roles in RBC integrity, enzymatic functions, and transport.
• These BGAs can also trigger autoimmune hemolytic anemia, hemolytic disease of the newborn, and transfusion reactions due to autoantibodies and alloantibodies.
• Sickle cell disease pathophysiology involves RBC adhesion molecules linked to BGAs.

Purpose of the Study:

• To review the physiological and pathological functions of BGA-bearing molecules on RBCs.
• To discuss strategies for providing safe blood transfusions for patients with RBC autoantibodies.
• To describe novel approaches for developing universal donor or "stealth" RBCs.

Main Methods:

• Review of literature on BGA functions, RBC autoantibodies, and transfusion challenges.
• Discussion of an algorithm for identifying hidden alloantibodies in patients with autoantibodies.
• Description of two methods for modifying RBCs: enzymatic removal of A/B antigens and surface coating with polyethylene glycol (PEG).

Main Results:

• BGAs are associated with RBC membrane integrity, hemolytic anemia, and enzymatic/transport functions.
• Clinical strategies exist to manage patients with RBC autoantibodies, avoiding suboptimal transfusions.
• Enzymatic modification can convert A, B, and AB RBCs to group O, while PEGylation creates "stealth" RBCs, with promising in vitro and in vivo data.

Conclusions:

• Understanding BGA functions is crucial for managing transfusion-related complications.
• Careful patient assessment and advanced techniques are necessary for transfusing patients with autoantibodies.
• Development of universal donor or stealth RBCs offers potential solutions for transfusion compatibility issues.