Lewis SYSTEM (007)

Question 1

The Lewis blood group antigens are synthesized by the RBCs. Lewis antigens are strongly expressed at birth

True or False?

Answer 1

False

Lewis blood group antigens are not synthesized by the RBCs. These antigens are adsorbed from plasma into the RBC membrane. Lewis antigens are poorly expressed at birth.

Question 2

What would be the RBC Ag present and phenotype if the Le gene arrangement is

LeLe/Lele sese

Answer 2

RBC Ag: Le^a
Phenotype: Le (a+b-) “non-secretor”

Secretion/Plasma: Le^a

Question 3

What would be the RBC Ag present and phenotype if the Le gene arrangement is

LeLe/Lele Sese or Sese

Answer 3

RBC Ag: Le^b
Phenotype: Le (a-b+) “secretor”

Secretion/Plasma: Le^a, Le^b

Question 4

What would be the RBC Ag present and phenotype if the Le gene arrangement is

lele SeSe or Sese or sese

Answer 4

RBC Ag: none
Phenotype: Le (a-b-) “secretor or non-secretor”

Secretion/Plasma: none

note: le gene - amorpha/silent

Question 5

Le gene is expressed in chromosome ____?

Answer 5

Chromosome 19

Question 6

Generally, Lewis antibodies are what type of immunoglobulin?

Answer 6

IgM (naturally occuring)

Question 7

Most common Ab in Lewis system; sometimes reacts at 37C; rare HTR has been reported:

Answer 7

Anti-Le^a