By Pat Anson, Editor
A new study by British researchers has demonstrated the potential for an experimental blood test that can diagnose arthritis in its earliest stages. Such a test could lead to earlier treatment of osteoarthritis (OA) and rheumatoid arthritis (RA), years before joint damage and physical symptoms begin.
Researchers at Warwick Medical School recruited 225 people with early or advanced OA, RA or another inflammatory joint disease, along with a control group of healthy volunteers with no joint problems. Their blood and fluid from affected knee joints were then analyzed with mass spectrometry.
The test found patterns in blood plasma amino acids that were damaged by oxygen, nitrogen and sugar molecules. The damage was highest in the blood samples of patients with OA or RA, and markedly lower in the blood of healthy volunteers -- giving researchers identifiable biomarkers that could be used for an early diagnosis.
“This is a big step forward for early-stage detection of arthritis that will help start treatment early and prevent painful and debilitating disease,” said Naila Rabbani, PhD, of Warwick Medical School. “Damage to proteins in the arthritic joint have been known for many years but this is the first time it has been exploited for early-stage diagnosis.
“For the first time we measured small fragments from damaged proteins that leak from the joint into blood. The combination of changes in oxidised, nitrated and sugar-modified amino acids in blood enabled early stage detection and classification of arthritis – osteoarthritis, rheumatoid arthritis or other self-resolving inflammatory joint disease."
Rabbani says the blood test could be available to patients within two years. Her study is published online in Arthritis Research and Therapy.
Osteoarthritis is a progressive joint disorder caused by painful inflammation of soft tissue, which leads to thinning of cartilage and joint damage in the knees, hips, fingers and spine. The World Health Organization estimates that about 10% of men and 18% of women over age 60 have osteoarthritis. There currently is no diagnostic blood test for osteoarthritis.
Rheumatoid arthritis is a chronic autoimmune disease in which the body’s own defenses attack joint tissues, causing swelling, inflammation and bone erosion. About 1.5 million Americans and 1% of adults worldwide suffer from RA.
A blood test for RA is already on the market in the United States, Canada, Europe, Japan and Australia. The JOINTstat test looks for a protein that is usually found at high levels in the joints of people with RA.