First described when rabbits were injected by Wiener and Landsteiner with a different animal's blood, FTP, identify this blood protein, separate from the ABO group and which was named for a certain type of monkey.
One cytotoxic reaction to it is the Type II hypersensitivity reaction in newborns known as erythroblastosis fetalis.  When blood-donors are not properly screened for its presence, hemolysis can result in transfusion recipients as a result of their bodies producing agglutinins in response to its introduction.  First described when rabbits were injected by Wiener and Landsteiner with a different animal's blood, FTP, identify this blood protein, separate from the ABO group and which was named for a certain type of monkey.
One cytotoxic reaction to it is the Type II hypersensitivity reaction in newborns known as erythroblastosis fetalis.  
Rh or Rhesus Factor