THERE MAY BE A NEW EXPLANATION FOR CHRONIC PAIN

Chronic pain is one of the most intractable problems of modern medicine.

A range of conditions cause people to suffer persistent pain, which does not respond well to medication, and for which no clear physical cause can be found.

But an explanation may now have emerged for some people with long-term pain, including those with fibromyalgia and complex regional pain syndrome.

The cause could be that their immune system has started making antibodies that damage their own tissues. These are called auto-antibodies.

In other words, some forms of chronic pain could be an autoimmune condition – similar to conditions such as multiple sclerosis and type 1 diabetes, where the immune systems attacks our own body.

The theory – which was recently presented at the British Pain Society annual meeting – could lead to new treatments and blood tests to identify those who have auto-antibodies.

“The importance of this type of work is that it moves some pain from the purely psychological to the biomedical,” said Dr Rajesh Munglani, vice-president of the British Pain Society.

But experts have warned that the theory first needs to be confirmed in larger studies and if it is correct, it is unlikely to apply to all people with unexplained pain.

Antibodies against ourselves

The antibody theory started with work by Professor Andreas Goebel, a pain specialist at the University of Liverpool, who found auto-antibodies in some people with a rare condition called complex regional pain syndrome (CRPS), often triggered by a physical injury.

Everyone has antibodies in their blood that react against lots of different things, for instance, bacteria and viruses that we have previously been infected with. They help us fight off these germs if we meet them again.

But in some autoimmune diseases, such as type 1 diabetes, people have antibodies that react to molecules within their own body, called auto-antibodies, which contribute to the pain and inflammation.

Professor Goebel found that when antibodies from people with CRPS are injected into mice, they cause pain symptoms in the animals, unlike if they received antibodies from people who do not have CRPS. This suggests that people with CRPS also have auto-antibodies.

CRPS is quite rare, but similar auto-antibodies also seem to be behind some cases of fibromyalgia, one of the most common unexplained pain conditions, affecting up to 1 in 25 people.

In fibromyalgia, people have pain all over their bodies, as well as other symptoms like fatigue and gut problems.

The question is what are the auto-antibodies reacting against? In fibromyalgia, they may be attacking glial cells, which wrap around and support nerves in the spinal cord, according to research by Professor Camilla Svensson, a pain physiologist at the Karolinska Institute in Sweden.

In tests, people with fibromyalgia had higher levels of glial cell auto-antibodies than people without the condition and those with more severe fibromyalgia pain had higher levels than those in less pain.

For people where auto-antibodies are playing a role, they could in future be removed with ‘blood washing’ treatments, or certain drugs that kill cells that make antibodies.

But only four in 10 fibromyalgia patients had any of these auto-antibodies, according to Professor Svensson’s work. So they can’t be the whole story behind fibromyalgia.

Psychological factors – a rival theory

The standard advice given to people with fibromyalgia in the UK is that there are no specific treatments, but people should reduce stress and try exercising if possible, although this is obviously hard for people who are in severe pain.

One theory is that rather than the symptoms being caused by physical damage, instead, feedback to the brain from muscles and other parts of the body starts to be wrongly interpreted as pain.

And this process can be reversed by “brain retraining” techniques, where people get used to doing things that can trigger pain while using psychological techniques like deep breathing exercises.

If the auto-antibody theory is correct, it might seem to be in stark contrast with the psychological approach.

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But Professor Deepak Ravindran, director of Berkshire Pain Clinic, said he thought the antibodies would be found responsible in only a small fraction of people with fibromyalgia.

And so far, the antibodies have only been investigated in a few chronic pain conditions.

Dr Munglani said that the term fibromyalgia may be being used for people with different disease processes going on, with psychological factors more involved in some, and biological processes responsible in others.

“It’s unlikely to be a single disease entity,” he said. “It is really a constellation of symptoms.

But [the research] does suggest that in quite a number of cases we are dealing with a biomedical course.”

Even Professor Svensson says we should not rule out psychological factors playing a role in people who have auto-antibodies. “Perhaps certain individuals that are under psychological stress may be more prone to developing an auto-immune condition,” she said.

2025-06-14T09:29:49Z