A breakthrough in lupus could be used to treat other autoimmune conditions.
That's according to Professor Luke O'Neill, who was speaking following a small test using so-called 'smart' T-cells to eliminate disease-causing B-cells.
Lupus is a long-term condition that causes joint pain, skin rashes and tiredness.
There's no cure, but symptoms can improve if treatment starts early.
Lupus, also called systemic lupus erythematosus, is not always easy to diagnose because it can be similar to other conditions.
Prof O'Neill was speaking from an immunology congress in São Paulo, Brazil.
He told Pat Kenny: "All the talk is of this big breakthrough that's happened in the disease lupus.
"It's still early days, but they seem to have actually put five people with lupus into remission for months and months - which is a big breakthrough.
"Lupus is a very nasty autoimmune condition which is difficult to treat".
Prof O'Neill said this could potentially be applied to other conditions.
"It's creating huge excitement because if it works in lupus, it could well work in other autoimmune diseases like arthritis, MS, Type 1 diabetes.
"This approach has really given real hope".
How does it work?
He said the breakthrough involved a drug that is used to 'hunt' B-cells causing the problem.
"The most recent one is a drug that targets B-cells - B-cells make antibodies.
"They've a drug that targets B-cells, it's called Benlysta and that works a bit, and that's what's inspired this new breakthrough.
"There's a clever way now to eliminate the mischief causing B-cells.
"What you do is you take bloods from someone with lupus, and you purify out the T-cells.
"T-cells are a very important part of the immune system, of course, but in this case you engineer the T-cells to go back into the person's body and hunt down these disease-causing B-cells.
"So in other words, you kind of make the T-cells smart.
"And what they showed is that one infusion of this approach cleared all the nasty B-cells from the lupus patient's body.
"And then almost immediately the symptoms began to resolve.
"And what was tremendous was one patient, 17 months later, she's still in remission.
"They're using the 'cure' word here almost, because this woman has effectively been cured for 17 months".
Prof O'Neill added: "It's a dream come true, in many ways, for resetting the entire immune system.
"There's talk already of trials now, in multiple autoimmune diseases on the back of this lupus study".