A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system. Some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens can stem from one allele (or very closely linked genes) and collectively form a blood group system. Blood types are inherited and represent contributions from both parents. A total of 30 human blood group systems are now recognized by the International Society of Blood Transfusion (ISBT).
Many pregnant women carry a fetus with a blood type different from their own, and the mother can form antibodies against fetal RBCs. Sometimes these maternal antibodies are IgG, a small immunoglobulin, which can cross the placenta and cause hemolysis of fetal RBCs, which in turn can lead to hemolytic disease of the newborn called erythroblastosis fetalis, an illness of low fetal blood counts that ranges from mild to severe. Sometimes it can be lethal for fetus called hydrops fetalis.
Read more about Blood Type: Blood Group Systems, Blood Group Genotyping, History, Society and Culture
Famous quotes containing the words blood and/or type:
“In my blood there is no Jewish blood.
In their callous rage, all antisemites must hate me now as a Jew.
For that reason I am a true Russian.”
—Yevgeny Yevtushenko (b. 1933)
“It took six weeks of debate in the Senate to get the Arms Embargo Law repealed—and we face other delays during the present session because most of the Members of the Congress are thinking in terms of next Autumn’s election. However, that is one of the prices that we who live in democracies have to pay. It is, however, worth paying, if all of us can avoid the type of government under which the unfortunate population of Germany and Russia must exist.”
—Franklin D. Roosevelt (1882–1945)