The Lutheran antigen systems is a classification of human blood based on the presence of substances called Lutheran

antigen In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune respons ...

s on the surfaces of red blood cells. There are 19 known Lutheran antigens. All of these antigens arise from variations in a gene called BCAM (basal cell adhesion molecule). The system is based on the expression of two codominant alleles, designated Lua and Lub. The antigens Aua and Aub, known as the Auberger antigens, were once thought to make up a separate blood group but were later shown to be Lutheran antigens arising from variations in the BCAM gene. The

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological pr ...

s Lu(a+b−) and Lu(a+b+) are found at various frequencies within populations. The Lu(a−b+) phenotype is the most common in all populations, whereas the Lu(a−b−) phenotype is uncommon. Though present in the

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal dev ...

, it is seldom the cause of

erythroblastosis fetalis Hemolytic disease of the newborn, also known as hemolytic disease of the fetus and newborn, HDN, HDFN, or erythroblastosis foetalis, is an alloimmune condition that develops in a fetus at or around birth, when the IgG molecules (one of the five ...

or of transfusion reactions. Serology interpretation of antibody panel for blood group antigens

Notes

Blood antigen systems Transfusion medicine {{Immunology-stub