Wednesday, July 23, 2008

Blood Types

Blood (also called blood group) is a classification based on blood, the presence or absence of certain substances inherited antigen on the surface of red blood cells (erythrocytes). These antigens can be protein, carbohydrates, glicoproteine or glycolipids, depending on blood group system, and some of these antigens, are also present on the surface of other types of cells of various tissues. Some of these red blood cell surface antigens, which flow from one allele (or very closely related gene), which together form the blood system.

Blood types are inherited and represents contributions from both parents. A total of 29 human blood group system currently recognized by the International Society for blood transfusion (ISBT).

Many pregnant women to continue at various fruit-type blood from their own, and mother can form antibodies against the fetus BS. Sometimes these are maternal IgG antibodies, a small immunoglobulin, which can cross the placenta and because of hemolysis fruit BS, which in turn can lead to hemolytic born diseases, diseases of the blood counts small fruit, which can be temporary or treated , But it can sometimes be serious.

Blood group Systems

A total of 29 human blood groups are now recognized by the International Society of Blood Transfusion sanguine (ISBT). A full description of blood types, a complete set of 29 substances on the surface of RBCs individual and a blood types is one of many possible combinations of blood groups anti-genes. Regarding the 29 blood groups, more than 600 different blood groups anti-genes have been found, but many of them are very rare and are primarily in certain ethnic groups.

Almost always, an individual has the same blood type to life, but rarely a blood type individual changes by adding or removing an antigen on infections, autoimmune diseases or malignant. An example of this rare phenomenon is the case, Demi-Lee Brennan, an Australian citizen, whose blood type changed after a liver transplant. Another more often the effect that, in the blood is to amend a type of bone marrow transplant. Transplantation of bone marrow are a lot of leukemia and lymphoma, other diseases. If a person receives a bone marrow from someone who is another type ABO (for example, a model A patient receives a bone marrow O), the patient's blood to give, finally, is to convert the donor .

Some species are related with the blood of the legacy of other diseases, for example, the antigen Kell is sometimes related to the syndrome McLeod. Some types of blood can affect vulnerability to infections, is an example of resistance against malaria for certain types of view, if the person without the Duffy antigen. The Duffy antigen, probably as a result of natural selection, is less often in ethnic groups from areas with high prevalence of malaria.

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