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The Lewis antigen system is a human blood group system. It is based upon two genes on chromosome 19: FUT3, or Lewis gene; and FUT2, or Secretor gene. Both genes are ...
Carbohydrate antigen 19-9 (CA19-9), also known as sialyl-Lewis A, is a tetrasaccharide which is usually attached to O-glycans on the surface of cells. It is known to play a role in cell-to-cell recognition processes. It is also a tumor marker used primarily in the management of pancreatic cancer. [1]
The term human blood group systems is defined by the International Society of Blood Transfusion (ISBT) as systems in the human species where cell-surface antigens—in particular, those on blood cells—are "controlled at a single gene locus or by two or more very closely linked homologous genes with little or no observable recombination between them", [1] and include the common ABO and Rh ...
The i antigen is made of linear repeats, while the structure of the I antigen is branched. [3] Unlike most other blood groups, the two antigens are not encoded by different alleles; rather, I-branching enzyme converts i antigen to I antigen by adding branches. [5] [6] The gene encoding I-branching enzyme is located on chromosome 6. [6]
The term "Lewis" in the name comes from a family of people with a red blood cell incompatibility. The studies done on these individuals' red blood cells led to the discovery of sialyl-Lewis X. Sialyl-Lewis X is an important red blood cell antigen present on the glycolipids on the plasma membrane of the cell.
Most of these markers are proteins, but some are carbohydrates attached to lipids or proteins [Reid M.E., Lomas-Francis C. The Blood Group Antigen FactsBook Academic Press, London / San Diego, (1997)]. Galactoside 3(4)-L-fucosyltransferase (EC 2.4.1.65) belongs to the Lewis blood group system and is associated with Le(a/b) antigen.
The ABO blood group system is used to denote the presence of one, both, or neither of the A and B antigens on erythrocytes (red blood cells). [1] For human blood transfusions , it is the most important of the 44 different blood type (or group) classification systems currently recognized by the International Society of Blood Transfusions (ISBT ...
The LW blood system was first described by Landsteiner and Wiener in 1940. [1] It was often confused with the Rh system, not becoming a separate antigen system until 1982. The LW and RhD antigens are genetically independent though they are phenotypically related and the LW antigen is expressed more strongly on RhD positive cells than on RhD negative cells.