Scientists Develop First Blood Test For Osteoarthritis
Researchers have isolated a biomarker that could indicate the early onset of both osteoarthritis (OA) and rheumatoid arthritis (RA). The discovery could be developed into a blood test to differentiate between the conditions before the onset of symptoms, which could improve patient outcomes.
The new method uses mass spectrometry to quantify the presence of citrullinated protein (CP) and free hydroxyproline in body fluids. A study published in Scientific Reports by a team from Warwick University found that CP was detected in elevated levels in both patients with early-stage OA and RA, but anti-cyclic citrullinated peptide (anti-CP) antibodies were present only in patients with early-onset RA.
The Warwick team found that a “4-class diagnostic algorithm combining plasma/serum CP, anti-CPP antibody and hydroxyproline applied to a cohort gave specific and sensitive detection and discrimination of early-onset OA, RA and other non-RA inflammatory joint diseases.”
Though there are several blood tests that detect the anti-CP antibodies in early-stage RA patients, this is the first blood test to look at CP as well and use it as a differentiating factor.
“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,” said Naila Rabbani, lead researcher in the study, in a Warwick University press release. “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”
According to the researchers, this technology is a first-in-class tool to both diagnose OA and differentiate between the different types of early-stage arthritis. With an earlier diagnosis of the specific condition, clinicians can begin the appropriate therapy sooner.
“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,” said Rabbani, who added that the assay could be effective in diagnosing a number of inflammatory joint diseases.
The CDC estimates that over 52.5 million American adults suffer from arthritis, and 27 million of those have OA, making it the most common form of the condition. Approximately 1.5 million people suffer from RA. The medical treatment of arthritis costs Americans over $80 billion per year, and arthritis is the leading cause of disability in the U.S.
“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,” said Rabbani.