By Pat Anson, Editor

British researchers are developing a new blood test that could predict the likelihood of developing rheumatoid arthritis (RA) up to 16 years before the onset of symptoms. Such a test would substantially increase the early detection of RA and make treatment more effective.

Rheumatoid arthritis is a chronic autoimmune disease in which the body’s own defenses attack joint tissues, causing pain, inflammation and bone erosion.

Researchers at the Kennedy Institute of Rheumatology at Oxford University developed a blood test that looks for antibodies in a protein called citrullinated tenascin-C (cTNC), which is often found in high levels in the joints of people with RA.  

In a study of over 2,000 patients, the blood test diagnosed RA in about 50% of cases. The test also had a very low rate of false positives.

"What is particularly exciting is that when we looked at samples taken from people before their arthritis began, we could see these antibodies to cTNC up to 16 years before the disease occurred – on average the antibodies could be found seven years before the disease appeared,” said Professor Kim Midwood of the Kennedy Institute.

"This discovery therefore gives us an additional test that can be used to increase the accuracy of the CCP assay and that can predict rheumatoid arthritis, enabling us to monitor people and spot the disease early. This early detection is key because early treatment is more effective."

Early RA treatment focuses on suppressing the immune system to reduce inflammation and slow progression of the disease.

"Early diagnosis is key, with research showing that there's often a narrow window of opportunity following the onset of symptoms for effective diagnosis and control of disease through treatment. Furthermore, current tests for rheumatoid arthritis are limited in their ability to diagnose disease in different patients,” said Stephen Simpson, director of research at Arthritis Research UK, which funded the study.

"This could have great potential to help patients with rheumatoid arthritis get the right treatment early to keep this painful and debilitating condition under control."

A similar diagnostic blood test for RA is already on the market in the United States, Canada, Europe, Japan and Australia. The JOINTstat test looks for another protein called 14-3-3η. A recent study of 149 RA patients in Japan found that serum 14-3-3η levels can predict disease severity and clinical outcomes. Drugs that reduce 14--3-3η levels can delay the onset and severity of RA, and increase the chances of remission.

About 1.5 million Americans and 1% of adults worldwide suffer from RA.