Other Blood Groups

• The Lewis blood group system comprises antigens Lea, Leb, and Lec.
• Lewis Blood Group System has alleles of LE locus include Le (FUT3) and le
• Lewis Blood Group System is ISBT No. 007 and has a symbol LE
• The product of Le (FUT3) gene is an a-fucosyltransferase that adds fucose to soluble type 1 oligosaccharides
• LE antigens are not synthesized by the red cells but are passively absorbed into the red cell from soluble antigens present in plasma.
• Lewis antigen expression is affected by H, Se, and Le genes.
• Lewis Antigen are not expressed on cord RBC's and are often diminished on the mother's RBC's during pregnancy.
• Lewis Antigen are found on lymphocytes and platelets and on other tissues such as pancreas, stomach, intestine, skeletal muscle, renal cortex, and adrenal glands.
• Soluble Lewis antigens are found in saliva as glycoproteins
• The addition of single fucose molecule from the Le (FUT3) gene gives rise to the Leᵃ antigen
• Le(a-) phenotype has no Lewis antigen expression due to mutation or deletion of FUT2 gene
• The Se(FUT2) gene must first add fucose to type 1 chain to produce soluble H antigen.
• The Le(FUT3) gene adds a second fucose to the type 1 H antigen to produce the Leᵇ antigen.
• The four LE phenotypes are: Le(a+b-), Le(a-b+), Le(a-b-), and Le(a+b+).
• Le(a+b-), Le and 2 se genes inherited.
• Le(a+b-), Leᵃ antigen will be found in the secretions, but not soluble ABH antigen.
• Le(a+b-) are nonsecretors
• Le(a-b+), Le and 1 or 2 Se genes inherited
• Le(a-b+) are secretors
• Le(a-b+), Leᵃ and Leᵇ antigens will be found in the secretions as well as soluble ABH antigens.
• Le(a-b-), two le genes inherited
• Le(a-b-) can be secretors or nonsecretors based on the Se genes inherited
• Le(a+b+) are rare type
• Most neonates type as Le(a-b-) regardless of which Lewis genes they have inherited.
• Lewis antigen are resistant to treatment with the enzymes ficin and papain, dithiothreitol (DTT), and glycine-acid (EDTA).
• Reactivity of Lewis antibodies can be greatly enhanced by testing with enzyme-treated RBCs; hemolysis of enzyme-treated RBCs may be seen if serum is tested.
• Lewis Antibodies are naturally occurring and can be produced by Le(a-b-) individuals
• Anti-Leᵃ is usually IgM, but may also be IgG in total part
• Anti-Leᵃ reacts best at room temperature but may react at 37C
• Anti-Leᵃ can bind complement, therefore capable of triggering in vitro hemolysis
• Anti-Leᵃ may be associated with hemolytic transfusion reactions
• Anti-Leᵃ activity is enhanced by enzyme treatment
• Anti-Leᵇ usualy IgM, and reacts best at room temperature
• Anti-Leᵇ bind complement poorly
• Anti-Leᵇ activity is enhanced by enzyme treatment
• Anti-Leᵇ is not associated with HDN and rarely cause HTR.
• Lewis Antibodies may appear transiently during pregnancy in Le(a-b-) women, but disappear after delivery
• Lewis antigen neutralize Lewis antibodies. Because both anti-Leᵃ and anti-Leᵇ react with most cells on routine RBC panel. Lewis substance can be used to neutralize the antibodies and allow detection of any other antibodies present.
• Leᵃ antigen has an ISBT no. LE1
• Leᵇ antigen has an ISBT no. LE2