ABO and Rh Blood Group System
Karl Landsteiner observed that the RBCs of some individuals were agglutinated by the serum from other individuals and he noted the patter of agglutination. This marked the discovery of first blood group system.
This reaction between RBC and serum was due to the presence of Ags on RBC and presence of Abs in serum. The antigens on RBCs are termed as antigen A and antigen B and blood group system is based on this.
Blood group A would have Antigen A on RBC
Blood group B would have Antigen B on RBC
Blood group AB would have Antigen A and B both on RBC
Blood group O would have no Antigens on RBC
Rh blood group was named after the Rhesus monkey because it was 1st discovered in them. It is the second important blood group system after the ABO blood group system. Rh antigen plays an important role in hemolytic disease of the new born.
Presence of antigen D on RBC marks it Rh +ve blood and
Absence of antigen D on RBC marks it Rh -ve blood.
Antibodies in Serum:
Blood group A will have anti B Abs.
Blood group B will have anti A Abs.
Blood group AB will have none.
Blood group O will have both anti A and anti B Abs.