Blood type namely group A, group B, and group C. He defined that group A blood agglutinates with group B, but never with its own type. Similarly, group B blood agglutinates with group A. Group C blood is different in that it agglutinates with both A and B. This was the discovery of blood groups for which Landsteiner was awarded the Nobel Prize in Physiology or Medicine in 1930. (C was later renamed to O after the German "Ohne", meaning without, or zero, or null.) The group AB was discovered a year later by Landsteiner's students Adriano Sturli, and Alfred von Decastello.
Rh blood group system reacts more strongly with red cells homozygous for an antigen than cells heterozygous for the antigen (EE stronger reaction vs Ee). If anti-E is detected, the presence of anti-c should be strongly suspected (due to combined genetic inheritance). It is therefore common to select c-negative and E-negative blood for transfusion patients who have an anti-E. Anti-c is a common cause of delayed hemolytic transfusion reactions. Rh blood group system The Rh blood group system is one of thirty-five known human blood group systems. It is the second most important blood group system, after the ABO blood group system. The Rh