Landsteiner’s Law

Landsteiner’s Law, also known as Landsteiner’s Rule, is a principle in immunohematology formulated by the Austrian biologist and physician Karl Landsteiner, who is renowned for his groundbreaking work on blood groups. Landsteiner discovered the ABO blood group system in 1901, for which he was awarded the Nobel Prize in Physiology or Medicine in 1930. Landsteiner’s Law states that:

“Antibodies in the serum of an individual will react with antigens on red blood cells (RBCs) only if the individual lacks those antigens on their own RBCs.”

In simpler terms, Landsteiner’s Law explains the basis of compatibility and incompatibility reactions in blood transfusions. The presence of specific antigens (e.g., A, B) on the surface of red blood cells determines an individual’s blood group. When blood from a donor with certain antigens is transfused into a recipient lacking those antigens, the recipient’s immune system may recognize the donor’s antigens as foreign and produce antibodies against them. This can lead to an immune reaction, causing the recipient’s antibodies to attack and destroy the donor’s red blood cells, resulting in a transfusion reaction.

Conversely, Landsteiner’s Law also suggests that individuals lacking certain antigens on their own red blood cells will not produce antibodies against those antigens. For example, individuals with blood type O lack A and B antigens on their red blood cells and therefore do not produce anti-A or anti-B antibodies. However, they can produce antibodies against other blood group antigens, such as the Rh factor (anti-D).

Understanding Landsteiner’s Law is crucial for blood banking and transfusion medicine, as it guides the selection of compatible blood donors and recipients to prevent adverse reactions during blood transfusions. Compatibility is determined by matching the donor’s blood type with the recipient’s blood type, considering both the ABO and Rh blood group systems, as well as other minor blood group antigens.