– Queen Mary University of London

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The first blood test to diagnose inflammation of the heart muscle (myocarditis) could be used in just a year, following the discovery of a molecular signal in the blood by researchers at Queen Mary University of London funded by the British Heart Foundation (BHF). The research, published today in the journal Trafficoffers hope for a quick and inexpensive way to diagnose the disease.

Myocarditis is a difficult condition to diagnose. Symptoms include a temperature, fatigue, chest pain, and shortness of breath, all of which can be easily confused with other conditions. The gold standard for diagnosis is a heart biopsy, an expensive, invasive and risky procedure that can sometimes still miss signs of disease. It is estimated that one young person dies suddenly every week in the UK due to previously undiagnosed myocarditis.

Now a team of researchers led by BHF Professor Federica Marelli-Berg from Queen Mary University of London have found that the presence of T cells – a type of white blood cell – expressing a molecule called cMet in the blood strongly indicates that a person has myocarditis. They say levels of cMet-expressing T cells could be detected with a routine blood test which could cost less than £50 with results available within hours.

Researchers hope this discovery will improve the diagnosis of myocarditis and help people get the treatment they need sooner, reducing the risk of developing life-threatening complications such as abnormal heart rhythms or heart failure.

In the study, the researchers compared blood samples from several groups of patients, including 34 people with a final diagnosis of myocarditis. This showed that myocarditis patients had significantly higher levels of T cells with cMet on their surface compared to other groups, including heart attack patients and those without medical conditions.

These results add to the evidence that myocarditis is an autoimmune disease. The team discovered that cMet-expressing T cells are activated by molecules expressed by heart cells, producing an immune reaction against these cells that leads to inflammation of the heart muscle.

The researchers also found that in mice, T cells with the cMet molecule appeared to play a role in the development of the disease. Blocking cMet with a widely available drug reduced the severity of their myocarditis.

The team will take this discovery further in future studies and hope it will help them develop the first targeted treatment for myocarditis.

Professor Federica Marelli-Berg, Professor of Cardiovascular Immunology at the British Heart Foundation, said:

“Early intervention is crucial when treating myocarditis because, in some cases, it may only be a few weeks between the onset of symptoms and the development of heart failure. But without a diagnosis, doctors cannot not provide their patients with the right treatment.

“We think this myocarditis test could be a simple addition to the routine blood tests prescribed in doctors’ offices. Considered in combination with symptoms, the results could allow general practitioners to easily determine whether their patients have myocarditis.

“Although we still need to confirm these results in a larger study, we hope it won’t be long before this blood test is used routinely.”

Professor Sir Nilesh Samani, Medical Director of the British Heart Foundation, said:

“Myocarditis is a notoriously difficult disease to diagnose and unfortunately some patients will suffer irreversible heart damage due to the lack of accessible diagnostic tests.

“This blood test could revolutionize the way we diagnose myocarditis, allowing doctors to intervene at a much earlier stage to offer treatment and support. It would also reduce the need for the risky and invasive tests currently used, saving the NHS time and money and freeing up vital resources.

PATIENT STORY

Stephen Hughes died in October 2014 at the age of 23 following a diagnosis of myocarditis. His parents Hazel and Gary, from Hull, believe that this blood test when he started showing symptoms could have helped Stephen.

“Each stage of his illness took a long time. In February 2014, he started to feel tired, short of breath, and had stomach pains. His GP thought it might be a gastrointestinal problem. At this point, a blood test could have indicated the cause of his symptoms. Even though there is currently no cure for myocarditis, Stephen could have been offered medication and told to rest.

“In April Stephen’s legs swelled up and he was rushed to hospital. This is where the doctors told us he had a heart problem and first mentioned myocarditis. They then put him on medication.

Currently, the gold standard test for myocarditis is a biopsy, an invasive and risky procedure. “Doctors performed a biopsy in August as they undertook open-heart surgery on Stephen to fit a left ventricular assist device (LVAD) [a type of artificial heart pump used to treat people with heart failure]” explained Hazel.

“The biopsy confirmed that Stephen had myocarditis and, due to the damage it had caused, he would need a heart transplant. He was put on the urgent transplant list in August. A donor heart was found in October, but tragically the operation failed. Stephen died three days later, just 10 days before his 24th birthday.

Since his death, Hazel, Gary and Stephen’s friends have tirelessly raised funds to help fund myocarditis research. “We don’t want other families to lose someone they love, someone who has everything to live for. By supporting the research, we can hopefully save other families from the grief we have experienced,” Hazel said.

“Within months, Stephen went from a fit, healthy and lively young man to having severe heart failure and needing to be pushed around in a wheelchair. These discoveries are an extremely important step. We’ll never know for sure, but that test might have given it a chance, and maybe it’ll still be around today.

This research was also partially funded by Barts Charity.

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