ABOjärjestelmän

ABOjärjestelmän refers to the ABO blood group system, a classification of human blood based on the inherited properties of red blood cells. It was discovered by Karl Landsteiner in 1901. The system categorizes blood into four main groups: A, B, AB, and O. These groups are determined by the presence or absence of two specific antigens, A and B, on the surface of red blood cells, and the presence of corresponding antibodies in the plasma.

Group A blood has A antigens on the red blood cells and anti-B antibodies in the plasma. Group B blood has B antigens and anti-A antibodies. Group AB blood has both A and B antigens but neither anti-A nor anti-B antibodies. Group O blood has neither A nor B antigens but possesses both anti-A and anti-B antibodies. This immunological difference is crucial for safe blood transfusions. Transfusing incompatible blood can lead to a severe, potentially fatal, immune reaction where the recipient's antibodies attack the transfused red blood cells.

The ABO blood group system is inherited in an autosomal codominant manner. This means that individuals inherit one allele from each parent, and if both A and B alleles are inherited, the AB blood type is expressed. The O allele is recessive. The distribution of ABO blood groups varies geographically and ethnically. Understanding the ABO system is fundamental in medicine, particularly for blood transfusions, organ transplantation, and forensic science.