The study, published in Nature Medicine found that people with arthritis in long-term remission had a difference in cell function which could settle inflammation and 'teach' nearby cells to repair the joint.
Although treatment for rheumatoid arthritis has improved, some people with the condition do not respond well with many having unpredictable 'flare-ups' of the disease. Scientists now hope that by harnessing the benefit of these 'resolving' cells it could lead to new and more effective treatments.
The University of Glasgow led the study in collaboration with Fondazione A.Gemelli IRCCS in Italy and the Versus Arthritis funded Research into Inflammatory Arthritis Centre (RACE).
Professor Christopher Buckley, one of the RACE leaders and the Director of Clinical Research, Kennedy Institute of Rheumatology, University of Oxford said: "One of the holy grails in research into rheumatoid arthritis is how to help repair the joint. This is now a step closer as in this national collaboration (RACE) we have worked with colleagues in the Division of Rheumatology, and Fondazione A.Gemelli IRCCS to identify a key cell type that is missing and needs to be replenished in order to help patients who have active arthritis achieve remission of their disease. We hope that knowing more about this cell type will also allow us to predict when patients are like to have a flare in their disease."
The study looked at high resolution images of the joints of people with rheumatoid arthritis in long-term remission. The researchers found that the membrane that protects and lubricates their joints appeared normal, in contrast to the inflamed, swollen joints of severe arthritis.
The researchers found a crucial difference in the functions of cells called macrophages. In active arthritis these macrophages arrived from blood and caused inflammation and joint damage. People in long-term remission had a different type of macrophage that could resolve inflammation and instruct adjacent cells to repair the joint.
"The result of this study is a credit to the vision and teamwork of our multinational collaborators," said lead author Dr. Mariola Kurowska-Stolarska, from University of Glasgow and RACE. "We identified different types of macrophages, and our goal now is to discover treatments that will encourage development of resolving macrophages in the joint.
"This would be a useful additional strategy to current treatments that calm-down the aggressive macrophages in arthritis. In the meantime, the relative numbers of resolving macrophages or aggressive macrophages in the synovium, or joint, might be a good predictor of flare and an indicator of arthritis patients maintaining remission."