Common virus that causes mono identified as likely trigger for lupus autoimmune disease

A common childhood virus could be the hidden trigger behind lupus, a chronic autoimmune disease that affects millions of people worldwide, major new research has found.

The study, published this week in Science Translational Medicine, points to the Epstein-Barr virus (EBV) – a pathogen carried by more than 90 per cent of adults – as the likely cause of the disease.

“This is the single most impactful finding to emerge from my lab in my entire career,” said Dr William Robinson, a professor of immunology and rheumatology at Stanford University and the study’s senior author.

“We think it applies to 100 per cent of lupus cases".

Lupus causes the immune system to attack healthy tissues throughout the body. The condition causes inflammation that can affect the skin, joints, kidneys, heart, and nerves – and disproportionately affects women, who make up an estimated 90 per cent of cases.

While most people with lupus can manage their symptoms with medication such as the common painkiller ibuprofen, around 5 per cent develop life-threatening complications, the study said. There is currently no cure for the disease.

The virus that never leaves

Epstein-Barr virus is best known for causing mononucleosis or mono, also known as the "kissing disease". Most people catch it in childhood or adolescence through saliva, for example by sharing food or drinks or kissing.

“Practically the only way to not get EBV is to live in a bubble,” said Robinson.

“If you’ve lived a normal life,"he added, the odds of having it are nearly 20 to 1.

Once inside the body, the virus hides in immune cells called B cells, which are responsible for producing antibodies to fight infections.

Normally, these B cells help defend the body, but EBV can hijack them – turning a small number rogue and convincing others to join in an attack on the body’s own tissues.

That process, researchers found, appears to be what sparks lupus.

What scientists found

Until now, scientists knew that nearly everyone with lupus carries EBV, but the exact link remained unclear. The Stanford team used advanced sequencing technology to identify how the virus manipulates the immune system.

They found that in people with lupus, EBV-infected B cells are far more common: about 25 times higher than in healthy people.

The virus produces a protein called EBNA2, which switches on human genes that drive inflammation. These overactive B cells then trigger other immune cells to attack cell nuclei, a defining feature of lupus.

When enough of these rogue cells accumulate, a full-blown autoimmune response begins.

Robinson and his team believe the same viral response could play a role in other autoimmune disorders, such as multiple sclerosis (MS), rheumatoid arthritis, and Crohn’s disease.

The researchers said genetic factors, viral strain differences, or other environmental triggers may explain why certain people are more vulnerable to autoimmune conditions such as lupus.

Several companies are already working on vaccines to prevent EBV infection, with some clinical trials already underway. However, these vaccines would likely only protect people before exposure, meaning they’d need to be given early in life.