Buildups of artery-clogging fatty deposits that can cause heart attacks may result when a person's defense system turns against the body, researchers say.

Dr. William Hollander of Boston University said his latest research supports the theory he pioneered two decades ago: that hardening of the arteries is an autoimmune disease, in which the body mistakenly destroys itself.The theory has become a hot topic of research in recent years as doctors try to identify the forces that cause blood vessels to fill up with fatty deposits like rust-encrusted pipes.

This process, which doctors call atherosclerosis, results in a heart attack or stroke if a clot accidentally squeezes off the flow of blood.

"I would say that our findings indicate that immune factors play a key role in the formation of the fibrous lesions that are the fundamental cause of heart attacks and strokes," Hollander said.

Several other research teams around the world also are finding signs that antibodies and other proteins of the body's immune system play a role in triggering or speeding up this disease.

Hollander presented his latest evidence Monday at the annual scientific meeting of the American Heart Association. About 26,000 doctors and other health professionals are in Dallas to hear more than 3,000 scientific presentations.