Lewis-A Antibody in Clinical Practice: A Case Report

Area of Science:

• Immunology
• Transfusion Medicine
• Blood Banking

Background:

• Lewis blood group antibodies, particularly anti-Lewis antibodies, are generally considered clinically insignificant due to weak reactivity at 37°C.
• However, rare instances of hemolytic transfusion reactions (HTR) have been associated with these antibodies.

Observation:

• A case of a 58-year-old patient with naturally occurring anti-Lewis-a (Le-a) antibodies was identified during routine blood grouping.
• Lewis antigens are low-prevalence antigens, necessitating careful crossmatching for compatible blood units.

Findings:

• The patient's anti-Lewis-a antibodies, though typically reacting at lower temperatures, demonstrated potential to cause a hemolytic episode at 37°C.
• This reactivity can impair the lifespan of incompatible transfused red blood cells.

Implications:

• Transfusion of antigen-negative, crossmatch-compatible packed red blood cells is crucial for patients with anti-Lewis antibodies.
• Comprehensive donor registries with detailed phenotypic profiles are valuable for identifying compatible blood sources, especially in emergencies.