Lewis antigen system

Lewis antigen system is a human blood group system based upon genes of the fucosyltransferase enzyme family, specifically FUT3 and FUT2. The Lewis antigen system is named after the individual in whom the antigen was first identified, Mrs. Lewis.

History

The Lewis antigen system was discovered in 1946 by Robin Coombs, Arthur Mourant, and Rob Race. They identified the Lewis antigen in the blood of a pregnant woman named Mrs. Lewis, hence the name of the system.

Genetics

The Lewis antigen system is controlled by two genes on chromosome 19: FUT3 and FUT2. These genes encode the enzymes fucosyltransferase 3 and fucosyltransferase 2, respectively. These enzymes are responsible for the addition of fucose to precursor substances, thus forming the Lewis antigens.

Antigens

The Lewis antigen system includes two major antigens: Lewis a (Le^a) and Lewis b (Le^b). These antigens are not directly produced by the genes FUT3 and FUT2, but are instead formed by the action of these genes on precursor substances. The Lewis antigens are found on the surface of red blood cells and in body fluids.

Clinical significance

The Lewis antigen system has clinical significance in blood transfusion and organ transplantation. The presence or absence of Lewis antigens can affect the compatibility of blood or organs for transplantation. In addition, Lewis antigens are associated with susceptibility to certain infections and diseases, including Helicobacter pylori infection and Norovirus gastroenteritis.

See also

• ABO blood group system
• Rh blood group system
• Blood transfusion
• Organ transplantation