The Rh system (Rh meaning Rhesus) is the second most significant blood-group system in human-blood transfusion with currently 50 antigens. Type O is often called 0 ( zero, or null) in other languages. The original terminology used by Karl Landsteiner in 1901 for the classification was A/B/C in later publications "C" became "O". It has been hypothesized that ABO IgM antibodies are produced in the first years of life by sensitization to environmental substances such as food, bacteria, and viruses, although blood group compatibility rules are applied to newborn and infants as a matter of practice. The associated anti-A and anti-B antibodies are usually immunoglobulin M, abbreviated IgM, antibodies. The ABO system is the most important blood-group system in human-blood transfusion. Thus, transfusion can be considered safe as long as the serum of the recipient does not contain antibodies for the blood cell antigens of the donor. There is an agglutination reaction between similar antigen and antibody (for example, antigen A agglutinates the antibody A and antigen B agglutinates the antibody B).
Bone-marrow transplants are performed for many leukemias and lymphomas, among other diseases. Another more common cause of blood type change is a bone marrow transplant. Almost always, an individual has the same blood group for life, but very rarely an individual's blood type changes through addition or suppression of an antigen in infection, malignancy, or autoimmune disease. The two most important blood group systems are ABO and Rh they determine someone's blood type (A, B, AB, and O, with + or - denoting RhD status) for suitability in blood transfusion.Ī complete blood type would describe each of the 43 blood groups, and an individual's blood type is one of many possible combinations of blood-group antigens. As of 2021, a total of 43 human blood group systems are recognized by the International Society of Blood Transfusion (ISBT). īlood types are inherited and represent contributions from both parents of an individual.
Several of these red blood cell surface antigens can stem from one allele (or an alternative version of a gene) and collectively form a blood group system. Some of these antigens are also present on the surface of other types of cells of various tissues. These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system. Blood type (or blood group) is determined, in part, by the ABO blood group antigens present on red blood cells.Ī blood type (also known as a blood group) is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells (RBCs).