Britannica Sources used in this answer

Why did heart transplant results improve after cyclosporine became available?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Kidney transplant — transplant British surgeon Andrew Ready flushing a donated kidney during a transplant at Queen Elizabeth Hospital, Birmingham, England, 2006.

Heart transplant results improved significantly after the introduction of cyclosporine because it provided a highly effective method for combating immune rejection of the transplanted organ.1

Following the first human heart transplants in the late 1960s, many surgeons abandoned the procedure due to a lack of adequate therapy to prevent the body from rejecting the new heart. Cyclosporine, a stable cyclic peptide derived from an earth fungus, changed this by specifically targeting and inhibiting the function of T lymphocytes—the white blood cells responsible for attacking foreign tissues.123

By effectively suppressing the immune system without the extreme dangers associated with earlier, less precise agents, cyclosporine allowed for a rapid increase in the success and frequency of heart transplant procedures. Today, it remains a cornerstone of antirejection treatment, enabling many recipients to lead productive lives for years following their surgery.213