October 27, 1995
Media Contact: John Cramer
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Johns Hopkins scientists studying the immune system may have discovered why some lupus patients who produce anti-clotting antibodies are still at a high risk for strokes and heart attacks during flare-ups of the disease.
Researchers found that a normally harmless fat molecule promotes the formation of blood clots in these patients when it moves from the inner to outer surface of a cell. That also exposes the molecule to the immune system, which mistakes it for a foreign invader and makes antibodies that attack it, says Livia Casciola-Rosen, Ph.D., the study's lead author and an assistant professor of dermatology.
The scientists identified a protein that may prevent or reduce these clots, which often occur in the brain, heart, lung and legs. Called annexin 5, the protein may lead to a treatment for these potentially fatal complications of lupus, according to researchers. Annexin 5 binds to the fat molecule only after it moves to the cell's outer surface, preventing clotting, but it does not prevent the immune system from making antibodies that cause the painful symptoms of lupus, they say. The fat molecule probably moves to the outer surface during apoptosis -- a cell's built-in series of instructions to destroy itself -- when the mechanism for keeping the molecule inside is blocked, says Casciola-Rosen.
"There is still much work to do, but this protein may be able to stop strokes and other clotting disorders when these patients have flare-ups," says Casciola-Rosen.
In systemic lupus erythematosis (SLE), the immune system mistakenly produces antibodies against the body's own tissue. During flare-ups, according to recent research results at Hopkins, certain molecules are split inside of cells and the resulting fragments form clusters on the cell's outer surface, making the cell an easy target for immune attack.
The findings were presented this month at The American College of Rheumatology's 59th Annual Scientific Meeting in San Francisco. The study used cells from three people with lupus and four healthy people.
Other researchers in the study were Mark Schlissel, M.D., Ph.D., Antony Rosen, M.D. and Michelle Petri, M.D. The study was supported by the National Institutes of Health and the Dermatology Foundation.