WEDNESDAY, Sept. 1 (HealthDay News) -- Overactive blood platelets could trigger inflammation in those with lupus, but the anti-clotting drug Plavix might ease the painful symptoms of this autoimmune disease, a new study suggests.

Platelets, which are the colorless, disc-shaped blood cells that are key to clotting, are suspected to be involved in lupus, explained senior study author Dr. Patrick Blanco, of the University of Bordeaux in France, but "their precise role was poorly understood until now."

Systemic lupus erythematosus (SLE) is a chronic disease thought to develop when the body's own antibodies start attacking organs. Sufferers experience recurring pain and inflammation in many parts of their body. Some common symptoms include joint pain or swelling, muscle pain, fever with no known cause, and red rashes, often on the face, according to the U.S. National Library of Medicine.

The exact cause of lupus is unknown, although research suggests that both environmental and genetic factors contribute to the disease.

Presently, there is no cure for the disease, which can be fatal. Current treatments include steroids and chemotherapy-like drugs, but they have assorted toxic effects, the study authors noted.

Blanco and his colleagues theorized that blood platelets might be involved in lupus because of their known role in the inflammatory process. To test this theory, they examined the blood of 37 lupus patients and compared their platelets to those from individuals without the disease.

They found that platelets in people with lupus were abnormally "activated" -- they expressed too much of a protein that's involved in blood clotting. These activated platelets, in turn, triggered production of proteins called interferons, which are known to promote inflammation.

The authors found that destroying blood platelets in mice prone to lupus relieved symptoms of the disease. They also treated these mice with the antiplatelet drug clopidogrel (Plavix), which is commonly used in humans to treat heart disease and stroke. The mice showed reduced lupus symptoms and they lived three months longer than mice that weren't treated with the drug.

The results suggest that it's possible that such anti-clotting drugs could improve outcomes in patients with lupus, said Blanco. He and his colleagues are currently designing clinical trials in humans to test this possibility.

"While this is interesting, I think it's kind of early to get excited and say that this is a treatment or a cure. I would like to try this in a clinical trial," said Dr. Anca Askanase, an assistant professor of rheumatology at NYU Langone Medical Centers Hospital for Joint Diseases.

The mouse model the researchers used suggests that an antiplatelet drug "might have a benefit in human disease as well," Askanase said, although "the efficacy of the mouse model is not shutting down the disease; it's improving the disease by a little bit. They don't get cured."

"Always when you move things from an experimental model to humans, things could be different," she added. "But Plavix is easy to test out in people, because it doesn't do anything bad to humans."

The study finding was published in the Sept. 1 issue of Science Translational Medicine.

More information

There's more on lupus at the Lupus Foundation of America.