Karl Landsteiner, M.D.

Karl Landsteiner, M.D.

Karl Landsteiner was an Austrian Jewish physician, immunologist, and Nobel Prize-winner whose discoveries surrounding blood groups transformed medicine. In 1901, he identified the ABO blood group system, making it possible to match donors and recipients for safe blood transfusions. He later discovered the Rhesus (Rh) factor, a protein found on the surface of red blood cells, which further improved blood compatibility testing. These breakthroughs made modern transfusion and organ transplantation possible.

Landsteiner emigrated to the United States in the 1920s for better research opportunities following economic difficulties in Austria after World War I and continued his work at the Rockefeller Institute. In 1930, he was awarded the Nobel Prize for Physiology or Medicine for his discovery of human blood groups. In addition to his work in hematology, Landsteiner contributed to the discovery of the poliovirus alongside colleagues at Rockefeller, laying the groundwork for future vaccine development. He is widely regarded as one of the founding figures of modern immunology and transfusion medicine, and his work continues to save millions of lives each year.