杏吧原创

Infants who would normally have died because they lack a key immune organ can now survive to adulthood thanks to a thigh implant that produces immune cells for fighting infections.

About five out of every million children born in the US are missing a thymus 鈥� an organ above the heart where important immune cells called T-cells mature. Without this organ, children have no way of fighting infections and usually die before the age of 3.

at Duke University in North Carolina and her colleagues have spent almost three decades developing a thymus replacement for these children. On 8 October, the US Food and Drug Administration (FDA) approved their product 鈥� called Rethymic 鈥� after it was shown to dramatically boost life expectancy for children without a thymus.

One of the first infants to be experimentally treated with Rethymic in the 1990s is now older than 25, and another four are older than 18. 鈥淭he FDA approval is super exciting because families won鈥檛 have to worry every day about their children getting life-threatening infections,鈥� says at Children鈥檚 Hospital Colorado in the US.

Rethymic is made from thymus tissue donated by babies who have had parts of their thymus removed during corrective heart surgery. The tissues is then engineered to make it suitable for transplantation.

Thin strips of the engineered tissue are then surgically implanted into the thigh muscles of children without a thymus. This location was chosen because thigh muscles have abundant blood vessels that nourish the thymus tissue and allow it to successfully implant.

Once the thymus tissue is implanted, it gradually starts producing T-cells. A study published earlier this year of 105 children who received these implants found they were able to .

Of these children, 28 died, mostly in the first year after implantation before the thymus replacement was working at full capacity. But the remaining 77 are still alive, with the average time since surgery being eight years.

Hsieh hopes the FDA approval of Rethymic will allow more children to receive the treatment. She has cared for five children without a thymus since 2016, two of whom have died while waiting to access the treatment, and three who are still waiting.

Families of these children are under tremendous emotional and financial strain, says Hsieh. They constantly worry their child will get sick and die, they usually have almost no social contact out of fear of catching an infection, and they have to implement strict hygiene practices at home, she says. 鈥淎nd now there鈥檚 covid in the picture, there鈥檚 even more fear.鈥�

Many parents of affected children have to give up their jobs and move house so they can live near specialist hospitals, and their siblings often have to stop going to school so they don鈥檛 bring home a disease, says Hsieh.

聽at Enzyvant, a biotechnology company that has helped to develop Rethymic, says more children without thymuses should now be able to access the treatment. 鈥淔or too long, families have faced a reality that the brutal journey for [these] patients receiving supportive care only would end tragically,鈥� she says. 鈥淭he FDA approval of Rethymic will help patients access this desperately needed therapy beyond clinical study.鈥�

Sign up to our free Health Check newsletter for a round-up of all the health and fitness news you need to know, every Saturday