A drug that "blindfolds" white blood cells could provide a new way of treating rheumatoid arthritis, new research has shown.
The drug stops the destructive cells migrating to the joints, where they cause the typical damage associated with the disease.
Rheumatoid arthritis is an auto-immune disease in which elements of the immune system attack the body.
White blood cells called T-cells are key players in the process.
Study leader Dr Graeme O'Boyle, from the University of Newcastle, said; "Imagine that the damaged joint is covered in flags which are signalling to the white blood cells. Traditional treatments have involved pulling down the flags one by one but what we have done is use an agent which in effect 'blindfolds' the white blood cells. Therefore, they don't know which way to travel and so won't add to the damage."
The study, funded by the charity Arthritis Research UK, is published in the journal Proceedings of the National Academy of Sciences.
Scientists carried out studies on a genetically engineered mouse with a human-like immune system.
They discovered that a compound called PS372424 blocked the ability of activated T-cells to invade joints.
Only the specific T-cells implicated in rheumatoid arthritis are affected.
Professor Alan Silman, medical director of Arthritis Research UK, said: "Although modern treatments have changed the outcome for many patients with rheumatoid arthritis, firstly not all patients respond to them and secondly, even in those patients who do respond in some way, we can't completely get rid of the inflammation that damages their joints.
"This research is very exciting, as although it is in its early stages, if it can be transferred to humans it could shut down the inflammation that causes rheumatoid arthritis."
The next stage is to improve the drug-like properties of PS372424 with a view to preparing it for clinical trials.