Researchers from the University of Warwick in the UK have developed what could be the first blood test that detects and distinguishes between two different arthritic diseases: osteoarthritis (OA) and rheumatoid arthritis (RA). The potential test was the theme of a study entitled, “Biomarkers of early stage osteoarthritis, rheumatoid arthritis and musculoskeletal health,” published this week in 
Nature Scientific Reports.
Background Terminology:
- Biomarkers: A biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease.
- Algorithm: is a procedure or formula for solving a problem or conducting a test.
- Antibodies: used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, called an antigen.
There is currently no clinical test available to detect OA. There is however a test for RA, but it has numerous testing problems, low clinical utility, and cannot be used to differentiate between the two diseases.
About the Study:
In this study, researchers tested patients’ blood for certain biomarkers that could be utilized as a potential accurate clinical test. They did this by looking for three specific molecules in the patient’s blood:
- Citrullinated protein (CPs)
- Antibodies to CPs
- Hydroxyproline: a bone substance
Using a two step algorithm the researchers found that measuring all three molecules in the blood, could lead to an accurate test that both detected and differentiated between OA and RA.
When discussing the importance of these findings Dr. Naila Rabbani, Associate Professor, Metabolic & Vascular Health, Warwick Medical School, and lead study author, stated, “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. 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.”
Dr Rabbani continued, “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. 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.”
A patent for this test has been applied for and published under international publication number WO2014016584.
