People with higher levels of antibodies in their blood have a lower risk of heart attack, say researchers at Imperial College London. Their findings suggest that measuring the levels of antibodies in the blood could be an accurate gauge of a person's heart attack risk, and warn of the likelihood of having a heart attack within five years.

The study found a link between the amount of IgG antibodies in a person's blood and their risk of suffering a cardiac event, such as a heart attack. IgG antibodies protect the body against bacterial and viral infections.

Measuring IgG levels is simple and cheap, so the scientists suggest that their finding could make it easier in the future for clinicians to more accurately determine a person’s risk of having a heart attack, regardless of other factors including cholesterol and blood pressure levels.

Volunteers with the highest antibody levels had a 58 percent decreased risk of having a heart attack and a 38 percent lower risk of stroke.

"Linking a stronger, more robust immune system to protection from heart attacks is a really exciting finding," said lead researcher Dr. Ramzi Khamis

The five-year project studied people who had high blood pressure and had already suffered a heart attack or stroke. Researchers measured levels of total IgG and IgM antibodies, as well as levels of antibodies that are particular to an oxidized form of "bad" cholesterol, oxLDL. This form of LDL promotes the development of atherosclerosis, which is the build-up of fatty material in the artery walls that can lead to heart attacks.

The researchers found that the people who had higher levels of general antibodies as well as antibodies against oxLDL were less likely to have a heart attack. Total IgG levels showed the strongest association with reduced heart attack risk, independent of other risk factors such as cholesterol levels or blood pressure.

"We hope that we can use this new finding to study the factors that lead some people to have an immune system that helps protect from heart attacks, while others don't," said Khamis, who is a consultant cardiologist and Independent Clinical Research Fellow at the National Heart and Lung Institute, Imperial College London. "We also hope to explore ways of strengthening the immune system to aid in protecting from heart disease."

The study was published in the scientific journal EbioMedicine.