Heart disease is the leading killer in the U.S., but patients with lupus are particularly vulnerable. Young women with lupus are 50 times more likely to die of a heart attack than are young women who don’t have lupus, for example. Why lupus increases the susceptibility to heart disease has remained unanswered.
Dr. Kaplan and her colleagues suspected that immune system cells known as neutrophils are responsible for causing the artery injuries that lead to heart disease. Neutrophils are a type of white blood cell that normally help fight off infections. But in patients with lupus some of these cells may instead become harmful and trigger inflammation of the blood vessels.
To test their idea, the scientists first used whole-body scans and measures of blood vessel health to give patients an arterial checkup. Compared with the blood vessels of people who don’t have the illness, the arteries of patients with lupus were in worse shape. Their arteries were more likely to be stiff, inflamed and contain fatty buildup known as plaque. These changes to the arteries can cause blockages that that hinder blood flow which can lead to heart attacks or strokes.
The researchers’ analysis of neutrophils from the patients implicated the cells in this arterial damage. Patients with more of the abnormal, harmful neutrophils had more plaque. When the researchers analyzed the activity of certain genes in blood cells from the lupus patients, they found further evidence that the “bad” neutrophils were injuring the patients’ blood vessels.
“Our findings, suggest that, in the future, lupus patients could benefit from the development of compounds that alter abnormal neutrophil behavior,” noted Dr. Kaplan.