Asimple blood test could warn people whether they are likely to suffer a heart attack within five years, scientists believe.
Researchers have discovered that high levels of antibodies – molecules produced by the immune system – are linked to a low risk of heart problems, regardless of other risk factors.
Currently doctors use information such as age, sex, medical history, cholesterol levels and blood pressure to calculate the risk of future heart problems.
But the new test looks for levels of protective IgG antibodies which seem to shield the body from a heart attack even when cholesterol and blood pressure is high.
People with the highest number of antibodies had a 58 per cent lower risk of coronary heart disease or heart attack and a 38 per cent lower chance of suffering a stroke or other heart events during the five year trial period.
“Linking a stronger, more robust immune system to protection from heart attacks is a really exciting finding,” said lead researcher Dr Ramzi Khamis, consultant cardiologist at the National Heart and Lung Institute, Imperial College London.
“As well as improving the way we tell who is at the highest risk of a heart attack so that we can give them appropriate treatments, we now have a new avenue to follow in future work.
“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. We also hope to explore ways of strengthening the immune system to aid in protecting from heart disease.”
Coronary heart disease is the UK's single biggest killer and the leading cause of death worldwide.
The disease is responsible for nearly 70,000 deaths in the UK each year and most deaths from coronary heart disease are caused by a heart attack.
Measuring IgG is simple and cheap, so the scientists suggest that this finding may in the future make it easier for clinicians to more accurately determine a person’s risk of having a heart attack.
It could mean that people who are currently prescribed statins or beta-blockers no longer need the drugs because their immune systems are strong enough to protect them without help.
IgG is the most abundant form of antibody and is found within all bodily fluids. It is responsible for protecting the body against bacterial and viral infections.
The team at Imperial College London and University College London studied more than 1700 people who had enrolled in the Anglo Scandinavian Cardiac Outcomes Trial (ASCOT) because they were at risk of heart problems.
Over five and a half years, 470 suffered a heart attack or stroke and they were compared with a control group of 1,283 to see what was different. Those with the lowest levels of antibodies had the highest risk of attack.
Professor Dorian Haskard, co-senior author and BHF Professor at Imperial College London, said:
“These are very interesting findings linking the immune system to protection from heart disease.
“The study focused on patients under treatment for high blood pressure, and we now need to know if the link also applies to other groups at risk.”
Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, which helped fund the research, said:“Heart attacks devastate thousands of families across the UK each year and research like this is vital to improving diagnosis so doctors are able to act fast and try to prevent a potentially deadly incident.
“Whether measurement of IgG will become a valuable tool for improving prediction of heart attack needs more investigation, but this well-designed study does provide further evidence for the role of the immune system in heart disease and the protective effects of IgG.”
The research, published today in the scientific journal EbioMedicine.
