Dana Orange, a rheumatologist at Rockefeller University in the United States, was devastated: some people could not even bend their elbows while brushing their teeth, and others could not even hold their wallets.But at worst, Orange says, these rheumatoid arthritis attacks are completely unpredictable.However, a new study published recently may change that.
Orange and colleagues found that a newly discovered cell accumulates in the blood a few weeks before the onset of rheumatoid arthritis, which may cause joint inflammation.If researchers can diagnose or treat these cells, they can predict and even prevent the disease.
Dirk Elewaut, a rheumatologist at the University of Ghent in Belgium who was not involved in the study, said the new finding was interesting because it could help clinicians and patients control disease fluctuations more effectively.
Rheumatoid arthritis is an autoimmune disease that causes debilitating pain and irreversible joint damage.An estimated 1.3 million people in the United States are more than twice as likely to have the disease as men.Anti-inflammatory and immunosuppressive drugs can help control the condition, but their effectiveness may diminish over time, with one-third of patients taking them developing rashes.
To better understand how the condition changes day by day, Orange and colleagues decided to track messenger RNA fragments in the blood of five patients with rheumatoid arthritis.They wanted to know if there was a consistent change in the type of RNA circulating in the blood before symptoms appeared.
But the team believes that ideal follow-up requires patients to visit the laboratory at least once a week to draw blood.This was unrealistic for patients, so they had five volunteers collect their blood at home once a week, depending on the situation—similar to how some diabetics monitored their condition.
Researchers have also developed a new buffer solution that, when mixed with blood samples, can hold RNA for at least 24 hours, allowing patients to mail blood samples to the laboratory.
Researchers analyzed which RNA was most abundant before, during and after each patient reported symptoms, said Robert Darnell, a neurooncologist at Rockefeller University and author of the study's newsletter.They then matched the data to the known characteristics of the cells responsible for the inflammation, thus reproducing patterns of immune activity.
At this point, they found a "significant, unexpected (RNA) signal."Its source is mesenchymal cells, which develop into the body's connective tissue and fill the joints.This mesenchymal RNA continues to appear in each patient a few weeks before the onset of symptoms, and inflammation-related RNA appears synchronously with it.The team called these special cells PRIME cells.
To test their findings, researchers then sampled 19 other patients with rheumatoid arthritis and found that PRIME cells were much higher than healthy controls, the team reported in the New England Journal of Medicine recently.While the findings do not mean that PRIME cells cause attacks, these patterns suggest they are part of an inflammatory attack on joints, Darnell said.
The researchers also found RNA characteristics associated with immature leukocytes that peak a few days before PRIME cells become active.White blood cells are responsible for triggering cascade responses to immune activity, and dysfunctional white blood cells are associated with a variety of autoimmune diseases.Taken together, Darnell said, the findings suggest that PRIME cells can be mobilized by abnormal immune systems.
The findings could help researchers prevent rheumatoid arthritis.If PRIME cells are useful for diagnosis and treatment, "you can at least plan your life and even prevent symptoms, " Orange says.