Lea is an antigen associated with which blood group system?

Lea is an antigen associated with which blood group system?

• A. Lewis
• B. P
• C. MNSs
• D. Kidd

Answer: (A)

Lea is part of the Lewis blood group system, which includes the antigens Le^a and Le^b. These antigens are produced by a fucosylation reaction controlled by the FUT3 enzyme, and their expression on red cells is influenced by secretor status (FUT2) and by tissue/secreted factor availability. Lea arises when the Le gene activity creates Le^a, and in many individuals it is present on red cells due to absorption from plasma, especially if secretor status is negative. Leb, by contrast, requires the secretor gene to be expressed. So Lea being a Lewis antigen explains why the correct association is the Lewis system, not P, MNSs, or Kidd.

Lea is part of the Lewis blood group system, which includes the antigens Le^a and Le^b. These antigens are produced by a fucosylation reaction controlled by the FUT3 enzyme, and their expression on red cells is influenced by secretor status (FUT2) and by tissue/secreted factor availability. Lea arises when the Le gene activity creates Le^a, and in many individuals it is present on red cells due to absorption from plasma, especially if secretor status is negative. Leb, by contrast, requires the secretor gene to be expressed. So Lea being a Lewis antigen explains why the correct association is the Lewis system, not P, MNSs, or Kidd.