The field of healthcare formally known as transfusion medicine and popularly as blood banking was the test bed for the nascent field of immunology—long before immunology even had a name.
In 1665, an English physician Richard Lower successfully transfused blood from one dog to another. Shortly thereafter, he reported a successful sheep-to-man blood transfusion (properly known as xeno-transfusion). Apparently it was dumb luck, as subsequent attempts failed due to (immune) reactions*, which led to the prohibition of xeno-transfusions.
*Obviously the concept of an adverse antigenic reaction was centuries in the future.
The first successful human-to-human blood transfusion (properly known as allotransfusion) was performed by PS Physick, a Philadelphia physician in 1795. As with xenotransfusions, some allotransfusions were successful, others were not. Absent insight into the nature of the adverse reactions, would-be transfusionists were forced to shelve the procedure. Blood banking’s first successful product wasn’t even blood, but rather 0.9% NaCl (table salt) in sterile water (saline solution) which was used for intravascular volume support, a use for which it continues to this day. A saline solution’s supreme simplicity precludes an immune reaction: salt molecules are too small and too simple to awaken the immune system. Immune reactions occur when molecules are large enough and complex enough to be recognized as foreign (antigens) trigger production of highly specific proteins (antibodies) created by the immune system to neutralize them.
transfusion of packed red cells
It is with good reason that Karl Landsteiner (1868-1943), an Austrian physician, immunologist and virologist is known as the father of transfusion medicine. In 1900, he identified three major blood groups: A, B and C (which was later renamed O). He found serum from individuals with blood group A did not agglutinate red cells from other individuals with blood group A—but did those with group B, as group B individuals had anti-group A antibodies*. Similarly, serum from those with blood group B didn’t agglutinate red cells from those blood group B, but did agglutinate the red cells of those with group A because blood group A individuals have anti-group B antibodies.
*These antibodies have been termed natural antibodies, given that they occur without prior exposure of the host to the foreign antigens
Landsteiner postulated that his findings explained the previously unpredictable transfusion reactions and that if the blood donor and recipient blood groups were identical (matched in blood banking parlance, transfusion reactions wouldn’t occur. The first blood transfusion based on this work was successfully performed in 1907 at Mount Sinai Hospital in NYC, for which Landsteiner received the 1930 Nobel Prize in Physiology or Medicine. After the Great War ended in 1918, Austria was flat broke and couldn’t fund Landsteiner’s research. In 1923, he weighed anchor and sailed to America at the invitation of Simon Flexner, head of the Rockefeller Institute in NYC. He spent the remainder of his career at the Rock, further contributing to transfusion medicine by delineating blood groups M, N, P and Rh factor (which corresponds to the highly immunogenicD antigen.