A blood transfusion is the process of transferring whole blood or blood components directly into a patient’s circulatory system. Today, this procedure is a standard, life-saving measure used to treat severe blood loss from trauma or surgery, or to manage conditions like severe anemia and certain blood disorders. However, the history of transfusion is marked by centuries of dangerous, often fatal, experimentation. Early attempts were perilous because the underlying biology of blood compatibility was completely unknown, transforming a hopeful therapy into a deadly gamble.
Early Experiments with Animal Blood
The earliest documented attempts at blood transfusion began in the mid-17th century, following William Harvey’s description of blood circulation in 1628. Initial experiments involved transfusing blood between animals, with Richard Lower successfully transferring blood between dogs in 1665. This success quickly led to the risky step of attempting transfusions from animals to humans.
In 1667, Jean-Baptiste Denis, personal physician to King Louis XIV, performed the first documented xenotransfusion—the transfer of blood between different species—using lamb’s blood. Denis’s first patient, a 15-year-old boy, reportedly recovered after receiving a small quantity of the animal’s blood.
Subsequent attempts resulted in tragic outcomes, as the foreign animal blood triggered violent, often fatal, immune reactions. The human immune system recognized the animal red blood cells as foreign, leading to clumping and destruction. Due to these deadly results, xenotransfusion was legally banned in France and elsewhere around 1670, causing the entire concept of blood transfusion to be abandoned for over a century.
The First Human-to-Human Transfusions
The practice of transfusion was revived in the early 19th century, with the crucial shift from animal blood to human blood, though the procedure remained highly dangerous. The first documented human-to-human blood transfusion was performed by English obstetrician James Blundell in 1818. Blundell was motivated by the high mortality rate of his patients suffering from postpartum hemorrhage, or severe bleeding after childbirth.
Blundell designed specialized equipment, including a syringe and tubes, to transfer blood directly from the donor to the recipient, bypassing the need for storage. His first documented attempt in September 1818 involved a male patient who was near death from a stomach ailment. The patient received blood from several donors and briefly showed improvement before dying 56 hours later.
Blundell later achieved a measure of success by performing a series of transfusions on women suffering from childbirth-related blood loss, using their husbands as donors. He performed ten documented transfusions between 1825 and 1830, reporting that about half of them were beneficial to the patient. Even with human blood, the procedure was highly unreliable because the underlying cause of the deadly reactions—blood incompatibility—was still a mystery. Unpredictable fatalities continued to occur, leading the medical community to regard the procedure as a desperate measure.
The Discovery That Made Transfusion Safe
The breakthrough that transformed blood transfusion from a perilous gamble into a reliable medical procedure occurred at the turn of the 20th century. In 1900, Karl Landsteiner discovered the ABO blood group system. Landsteiner observed that mixing the blood of two people sometimes caused the red blood cells to clump together, a process known as agglutination.
He determined that this clumping was an immunological reaction caused by specific antigens (proteins) on the surface of red blood cells and corresponding antibodies in the blood plasma. Landsteiner initially identified three blood groups, which he labeled A, B, and C (later renamed O); the fourth group, AB, was identified shortly after by his colleagues. This discovery finally explained why Blundell’s transfusions were hit-or-miss: a reaction occurred when a recipient received incompatible blood that contained antigens their body’s antibodies would attack.
Landsteiner’s work made it possible to determine a person’s blood type and ensure that only compatible blood was transfused, a process known as cross-matching. This knowledge was quickly applied, and the first successful transfusion using ABO blood typing was performed in 1907. Further safety was achieved with the discovery of the Rhesus (Rh) factor by Landsteiner and Alexander Wiener in 1940, which addressed remaining transfusion reactions and issues related to pregnancy. These discoveries laid the foundation for modern transfusion medicine, making the widespread use of safe blood transfusions possible.