A ‘harmless’ virus carried by half of adults increases a person’s risk of heart disease by a fifth, new research suggests.
Being infected with cytomegalovirus (CMV), which is a cousin of the herpes virus and spreads via contact or bodily fluids, makes a person 20 per cent more likely to ‘catch’ heart disease.
CMV increases the number of immune cells a person has in their blood. Such cells are associated with the buildup of plaque in the arteries, which can prevent blood from reaching the heart and trigger a deadly attack.
Study author Dr Alejandra Pera, from Brighton and Sussex Medical School, said: ‘Our work shows that an infection by CMV is responsible for the accumulation of high numbers of immune cells that are linked to coronary heart disease.
‘They are a stronger indicator of cardiovascular death risk than age.’
The researchers investigated how a CMV infection affects a person’s heart health and premature death risk.
They analysed 215 healthy people aged between 60 and 94, as well as 27 19-to-32 year olds.
Blood samples were taken to determine how many memory immune cells the participants had, as well as if they were carrying CMV. Once infected, the virus stays in a person’s body for the rest of their life.
Memory cells are a type of immune cell that responds quickly when it encounters a pathogen for a second time.
Of the older participants, 122 carried CMV. They were included in the study due to memory cells naturally accumulating with age, as well as CMV infection rates being higher among the elderly.
Results, published in the journal Theranostics, suggest memory cells are twice as high in people infected with CMV. This may explain previous research that links CMV infections with stroke.
Although both CMV and memory cells are associated with older people, the link between the virus and the cells persists even after age is accounted for.
The researchers believe treating CMV-infected patients with anti-viral therapies may reduce their risk of heart disease. There is no CMV vaccine.
Alternatively, targeting the molecule IL-7, which triggers the production of immune cells after an infection, may also make CMV-infected people less vulnerable to stroke.
Co-author Dr Stefano Caserta, from the University of Hull, added: ‘We do not know whether IL-7 may also be behind the build-up of immune cells following CMV infection that some people may experience.
‘However, it does mean we are now discovering what we can do to finely tune the immune responses, so that in future we could tailor therapies around individual cases.’