Test diagnoses RA with better accuracy by detecting synthetic citrullinated peptides.
A reliable new blood test can test for rheumatoid arthritis (RA) years in advance. With about 1.5 million Americans suffering from the debilitating condition, according to the Centers for Disease Control and Prevention (CDC), early detection is key.
Researchers from the Kennedy Institute of Rheumatology at the University of Oxford in England discovered a biomarker that can predict the likelihood of developing RA. The blood test all starts by examining citrullination — the process where proteins are altered due to inflammation.
These changes can cause an immune response in the body where antibodies turn on themselves, which causes rheumatoid arthritis. Tests to detect these antibodies already exist, but with low sensitivity it is not the most reliable method. But a more general test called CCP can diagnose RA a lot more accurately by detecting synthetic citrullinated peptides.
“We knew that tenascin-C is found at high levels in the joints of people with RA. We decided to see if it could be citrullinated and, if so, whether it was a target for the autoantibodies that attack the body in RA,” lead researcher Anja Schwenzer, PhD, said in a news release.
The team looked at blood test results from more than 2000 patients who had not been diagnosed with arthritis. They were able to diagnose RA in about half of the cases — some of which weren’t identified by standard testing – by targeting citrullinated tenascin-C (cTNC).
The method has a very low false positives rates and is 98% accurate at ruling out RA, according to the report in the Annals of the Rheumatic Diseases.
“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,” explained Kim Midwood, BCs (Hons), PhD.
Early detection leads to more effective treatment, so not only does this additional test help increase the accuracy of the CCP assay, but it also helps spot RA way in advance which leads to better patient outcomes.
“This latest research provides the basis of tests that could improve diagnosis and, importantly, detect disease at a very early stage, with the promise even that people at risk of developing rheumatoid arthritis can be followed before the disease begins,” concluded Stephen Simpson, PhD, research director at Arthritis Research UK.