Immune system linked to lower heart attack risk: study

Researchers have found that people with higher levels of antibodies in their blood have a lower risk of heart attack, an advance which may make it easier for doctors to more accurately determine a person's risk of having a cardiac arrest.

The finding suggests that measuring levels of antibodies in the blood could be used to assess a person's heart attack risk, according to researchers from Imperial College London and University College London in the UK.

The study shows a link between the amount of IgG antibodies in a person's blood and their likelihood of being protected against an adverse cardiac event, such as a heart attack, researchers said.

IgG is the most abundant form of antibody and it is responsible for protecting the body against bacterial and viral infections, they said.

Measuring IgG is simple and cheap, so scientists suggest that this finding could, in the future, make it easier for clinicians to more accurately determine a person's risk of having a heart attack.

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

"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," said Khamis.

"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 do not," he added.

Researchers studied patients who suffered a heart attack or stroke from the Anglo Scandinavian Cardiac Outcomes Trial (ASCOT) with their matched controls. People enrolled on the ASCOT trial had high blood pressure and were at high risk of a cardiovascular event.

Researchers measured levels of total IgG and IgM antibodies, as well as levels of antibodies that are particular to an oxidised form of 'bad' cholesterol, oxLDL, which is known to promote atherosclerosis - the build-up of fatty material in the artery walls that can lead to heart attacks.

They 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, researchers said. 

The findings were published in the journal EbioMedicine.