[Science] Cell injections could train the body to accept a transplanted organ – AI

Organ donation without the risk of rejection could become a realityCraig Stennett / Alamy Stock Photo By Clare WilsonPeople having organ transplants in future may no longer have to take anti-rejection medicines, thanks to a new technique that makes their immune system see the donor’s tissue as their own. The method involves giving the recipient an infusion of the donor’s cells a week before the operation, so it wouldn’t work for those getting an organ from someone who has died – but would be suitable for those with a living donor, such as in some kidney, liver and pancreas cell transplants. When the technique was tested on five macaque monkeys, the transplanted pancreas cells stayed healthy without being rejected for up to two years. “It’s still very early days – but if it works it’s a complete game-changer,” says Chris Callaghan of Guy’s and St Thomas’ Hospital in London, who was not involved in the study. Advertisement Transplants of organs such as the kidney, liver and heart can be life-saving but at the moment recipients have to take medicines for the rest of their lives to damp down their immune system and avoid the new organ being rejected. These drugs have serious side-effects such as leaving people more prone to infections and cancer. So a way to force someone’s immune system to accept a new organ has been sought for decades. Remembering cells Bernhard Hering of the University of Minnesota in Minneapolis and colleagues exploited the way that our immune systems are trained not to attack our own cells. Throughout our lives, our cells naturally die through a process called apoptosis and are shed into the bloodstream. Immune cells in the spleen take in these dying cells and “remember” that their molecules signify the body’s own cells – not invading microbes – and so should be tolerated. It’s possible to mimic this process by treating cells with a chemical called ECDI that triggers apoptosis. Hering’s team induced a condition similar to type 1 diabetes in five macaques by killing insulin-producing cells in the pancreas. They then treated the sick monkey with a transplant of pancreas cells from donor monkeys. To see if long-term anti-rejection drugs could be avoided, the sick monkeys were given infusions of ECDI-treated blood cells from the donors, both one week before the transplant, and one day afterwards. They also received anti-rejection drugs for three weeks. Successful transplant Even when the anti-rejection drugs were stopped, the pancreas cell transplants stayed healthy and produced insulin for two years in one animal and one year in the rest, at which point they were killed so their tissues could be examined. This particular form of tissue donation is currently quite a rare treatment for people with type 1 diabetes because of the need for lifelong anti-rejection drugs. Most people prefer to treat their diabetes with insulin injections instead. The approach could also be used in people who receive a kidney from a living donor, says Hering. In the UK about a third of kidney transplants come from people who are still alive, usually relatives or friends, but sometimes a stranger. It’s also possible to donate part of the liver while you are still alive, as this organ regenerates almost completely. And a small number of people have donated part of their lung. Journal reference: Nature Communications, DOI: 10.1038/s41467-019-11338-y More on these topics: transplants