Dr. Suzanne Ildstad, director of the Institute of Cellular Therapeutics at the University of Louisville, pioneered the approach and led the trial with Leventhal.
"It really makes all work we've done really worthwhile," she said. "Being a transplant recipient isn't easy. They have to take up to 25 pills a day, keep track of them, suffer the consequences of them. There's really been no other way. ... These results are really gratifying."
Eliminating the need for anti-rejection drugs would mean healthier transplant recipients and longer-lasting organs.
"We would love for the first transplant a person gets to be the only transplant they need," said Leventhal, adding that many transplant recipients need a second transplant in their lifetime because of chronic rejection. "We hope that tolerance will be a pathway toward keeping that transplant for as long as they live."
This year, Leventhal and Ildstad will test the approach in patients who have already received a kidney transplant from a living donor. They hope transplanting bone marrow stem cells from the same donor even years after the organ transplant will reduce the need for anti-rejection drugs. They also plan to broaden the study to include other types of transplants.
Porter, now 47, is making the most of her new life free of kidney disease and anti-rejection drugs.
"I used to save my best hours to do something with my son," she said, describing the fatigue she felt during 5-year-old CJ's early years. "Now we're constantly running around on all kinds of adventures. ... I feel like someone just shaved 15 years off me. I went from feeling old to feeling great."
After losing loved ones to hereditary kidney disease, Porter said she is grateful to have had the chance to participate in the pioneering trial.
"This was some small thing I could do to honor them," she said. "Someone has to do it first."