Dubai, United Arab Emirates (CNN) — When Kaitlyn Cinnamon was 20 weeks pregnant with her second child, doctors told her he had a heart problem that required surgery at birth.
Easton Cinnamon was born at Duke University Hospital with a heart with only one ventricle instead of two, to pump blood to his body.
He underwent two heart surgeries, but they were unsuccessful in stopping a leaky valve linked to congenital heart disease, so it became clear to the surgical staff that Easton needed a new heart. But the transplant requires Easton to take immunosuppressive drugs for life so that his body does not reject the new organ. The effect of these drugs may increase the risk of developing cancer, and they may be toxic to the kidneys, in addition to exposing patients to more severe disease.
But another challenge faced doctors as Easton waited for a heart transplant. After he had recurrent infections, further tests revealed that he had a specific deficiency of immune system cells known as T cells, which mature in the thymus gland, located in front of the heart. And his weak functional immunity means that his body does not normally produce the T cells that are often responsible when the body rejects and attacks the transplanted organ, as well, when it does not recognize it.
“It was a coincidence that Easton needed a heart transplant and had a significant weakening of functional immunity,” Dr. Joseph Turek, chief of pediatric cardiac surgery at Duke University and a member of Easton’s surgical team, told a news conference Monday.
This made Easton a candidate for a new surgery, in which he receives a new heart and thymus from the same donor, which has never been performed on humans.
Easton’s parents, Caitlin and Brandon Cinnamon, made the decision to have their child undergo such a risky operation not easy, given the risks associated with the transplant. When Easton’s second surgery failed, Turek discussed options with the parents.
“I think the thing that stopped us the most was when he said, ‘I want to give you back your son,'” Kaitlin Cinnamon told CNN. “The only way to do that is through a transplant.” “If it works, it will help not only Easton, but millions of other people as well. Plus, we can make a huge difference. If it doesn’t work, we’ll try as little as possible.”
According to Turek, Duke University is the only place in the Western Hemisphere with thymus transplants, where donor cells are incubated to grow in the laboratory before being transplanted into the recipient.
If the immune system is healthy, immature immune cells enter the thymus gland, where they learn to recognize what is “self” and what is foreign. A thymus transplant removes any of the donor’s mature immune cells, leaving a vector from the recipient’s thymus gland through which to develop its own immune cells.
“The idea of the thymus growing in the same environment as the new transplanted organ allows it to be recognized as ‘autologous’,” Turek told CNN.
Easton’s immune deficiency means he may be able to develop one aspect of his immune system, T cells, as his body gets used to his new heart. This double transplant from the same donor can eliminate the need for serious lifelong immunosuppressive drugs.
In August, Easton had a heart transplant and started taking an immunosuppressant drug. Two weeks later, following the thymic cell transplantation was completed, the child underwent a thymic gland transplant.
Soon following the surgery, Easton was moved out of the intensive care unit, which means he is recovering well.
Six months following the transplant, tests demonstrated that the new thymus gland was developing T cells correctly and that his body had not rejected his new heart. Those results are promising, and Easton’s medical team hopes to get him off his immunosuppressive drug within a year if tests confirm that his T cells recognize his transplanted heart as his.
“The idea that you can have a transplant and not have to take these drugs is a game-changer for transplant patients,” Turek told CNN.
Turek also said that the success of the procedure might mean the transplanted heart can live longer than the usual 10 to 15 years, due to episodes of rejection in the years following the transplant.
These attacks are usually treated by increasing the dose of immunosuppressive drugs, which may affect the integrity of the heart over time. So building an immune system that can withstand a heart transplant can increase the durability of this heart.
Turek told CNN that if this is achieved, this method will be adopted in most transplants in the future, and it will be transient for all organs.
But T cells are only one part of the immune system’s response to transplanted organs, noted Dr. Reshma Beniwal, associate professor of cardiac surgery and director of pediatric heart transplantation at UCLA.
“I would be very hesitant to say that the child would be completely free of any immune rejection, because this is only T-cell technology,” said Pennywall, who is not part of Easton’s medical team. “Immunity is also elicited by antibodies by humoral cells (B cells), which require an entirely different mechanism of immunosuppression.”
B cells are a type of immune cell that makes antibodies and form in the bone marrow.
“This might be a great solution in the short term, but it doesn’t provide a lifelong solution,” Peniwal told CNN. “It’s unclear whether this procedure would be viable in an adult patient, according to Turek, because the thymus shrinks with age and the bone marrow becomes responsible,” Benewall told CNN. on the formation of T cells.
“That’s one of the things that we look for in the lab, as well as the age of our donor. We think it’s likely to be somewhere in early adulthood when you still have a transplantable thymus gland,” Turek explained.
Seven months following his surgeries, Easton celebrated his first birthday “homegrown,” according to Cinnamon.
“When we brought him home, he mightn’t even raise his head,” she said. “We had to hold him like a newborn, and now he’s walking around the house laughing and playing with his sister on the floor.” “If you look at him now, you won’t know that he’s experienced everything he’s been through,” she added.