Cyclosporin 1972 – Transplanted Organs Are No Longer Rejected

Organ transplants, moving an organ from one body to another, increased people's chances of survival in the 1960s. However, the recipient's body often rejected foreign donor tissue.  

Journalist Richard Hollingham wrote: “Organ transplants increasingly came to be seen as a desperate measure of increasingly desperate surgery.” 

It was pure chance that surgeons would soon gain a new ally in their search to save lives. 

Immunosuppressive drugs, which suppress the body's immune system, help prevent rejection of transplanted organs. In 1972, researchers at Swiss pharmaceutical company Sandoz applied a screening test designed by Dr Hartmann Stähelin. They discovered the immunosuppressive effects of a fungus-derived compound, cyclosporin, abbreviated Cy and also known as cyclosporin and cyclosporine.

British surgeon Roy Calne and colleagues demonstrated the drug's success in kidney transplantation. In 1983, it was approved in the United States for use in all transplant patients.

American physician Thomas Starzl showed that Cy worked best when given with steroids and demonstrated its success in reducing organ rejection in liver transplantation. 

Journalist Barry Werth wrote: 

“Cyclosporin made Tom Starzl the world's most famous and influential transplant specialist. Transplants, once terrifying and dreadful, now shone with optimism... There seemed no limit to what Starzl could do. In 1984... he replaced both the heart and liver of a six-year-old girl who was skipping around the hospital within two weeks.”

Cy is remarkable because it allows selective inhibition of T cells (a type of white blood cell) without excessive toxicity, while leaving much of the body's immune system able to fight general infections. It was the first powerful immunosuppressive drug. However, it is not perfect and may not prevent every rejection. Transplant recipients must take Cy indefinitely. It may also cause kidney damage and increase cancer risk. 

In the 25 years after its discovery, approximately 200,000 patients relied on Cy to undergo transplantation. 

Description of the article image: A molecular ribbon diagram of human cyclophilin A, a protein, complexed with cyclosporin (yellow). The complex inhibits an enzyme, stopping production of proinflammatory molecules and thereby suppressing organ rejection.

Historical figures mentioned in the article: Hartmann F. Stähelin (b. 1925), Thomas E. Starzl (b. 1926), Roy Yorke Calne (b. 1930)

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