Biomarker discovery could lead to diagnostic blood test for rheumatoid arthritis and osteoarthritis

Research from the University of Warwick (UK) could be the first step in developing a blood test for osteoarthritis (OA). The team identified a biomarker that is linked to both rheumatoid (RA) and osteoarthritis, which could allow for diagnosis of both conditions several years before the onset of physical symptoms. The research was recently published in Nature Scientific Reports.

While there are established tests for RA, this new research could lead to a test capable of diagnosing both RA and OA. The team’s research focused on citrullinated proteins (CPs), a biomarker suspected to be present in patients with early-stage RA. They identified increased CP levels in early-stage RA, but also in early-stage OA, these increased CP levels in early-stage OA had previously been thought not to occur.

The team then produced an algorithm of three biomarkers – CPs, anti-CP antibodies, and the bone-derived substance hydroxyproline. Applying this algorithm, the team determined that with a single test they could potentially detect and categorize major types of arthritis in its early stages, prior to joint damage occurring.

Lead researcher Naila Rabbani (University of Warwick) explained: “This is a remarkable and unexpected finding. It could help bring early-stage and appropriate treatment for arthritis which gives the best chance of effective treatment.”

In describing the role of CPs in relation to arthritis and the importance of the team’s algorithm, Rabbani elaborated, “It has been long established that the autoimmunity of early-stage RA leads to antibodies to CPs, but the autoimmunity, and hence antibodies, are absent in early-stage OA. Using this knowledge and applying the algorithm of biomarkers we developed provides the basis to discriminate between these two major types of arthritis at an early stage.”

The ability to discriminate between OA and RA could allow for early diagnosis, providing benefits for patients. Rabbini commented, “Detection of early-stage OA made the study very promising and we would have been satisfied with this only – but beyond this we also found we could detect and discriminate early-stage RA and other inflammatory joint diseases at the same.”

She concluded: “This discovery raises the potential of a blood test that can help diagnose both RA and OA several years before the onset of physical symptoms.”

Sources: Ahmed U, Anwar A, Savage RS et al. Biomarkers of early stage osteoarthritis, rheumatoid arthritis and musculoskeletal health. Scientific Reports DOI:10.1038/srep09259 (2015) (Epub); First blood test for osteoarthritis could soon be available.