Claire Bergstrom Johnson vividly remembers the moment her childhood changed for ever.
At the age of seven her non-identical twin, Maegan, suddenly collapsed in the school playground.
‘I remember running when the bell rang to go back inside from recess and found her on the ground in the sandpit, unable to get up,’ Claire, now 30, recalls.
‘Maegan kept trying to get back up but she just couldn’t. I thought she was joking.’
As Maegan was carried inside, teachers initially suspected uncharacteristic bad behaviour, until the little girl explained she simply couldn’t stand. She managed to do so later that day but was stumbling around, bumping into things.
On reflection, her mother, a veterinarian, had noticed some worrying signs over the previous few months. As Claire explains: ‘Maegan had become clumsy, frequently running into things and then screaming in pain.
‘When she went downstairs, she had started to grip the bannister, take one step at a time and planting both feet before attempting the next.’
And so after she collapsed, her parents took Maegan to the family doctor, who ordered some blood tests.
Claire Bergstrom Johnson vividly remembers the moment her twin sister Maegan suddenly collapsed in the school playground
When these didn’t reveal what was wrong, Maegan was referred to a local children’s hospital where she was diagnosed – incorrectly – with Charcot-Marie-Tooth disease, a group of inherited conditions that damage the peripheral nerves.
But she continued to deteriorate.
‘Within a week of that visit Maegan was visibly worse,’ says Claire.
‘She could walk but was very sensitive to things. For example, the contrast between warm bath water and the cooler air around her made her scream in pain; even a simple bump or nudge could be very painful. She also experienced sudden muscle weakness and falls.’
The doctors were baffled, often dismissing the family’s concerns – her mother was labelled a ‘hysterical helicopter parent’ by some clinicians.
Maegan was then referred to more specialised assessments at the Mayo Clinic some 500 miles away from the family home in Holland, Michigan, in the US.
After undergoing rounds of investigations, such as nerve conduction tests, which measure the speed and strength of electrical signals travelling through your nerves, she was diagnosed – incorrectly, again – with Guillain-Barré syndrome (GBS), an autoimmune disorder where the immune system attacks the peripheral nerves.
Maegan was hospitalised for two weeks and treated for GBS. When she was discharged, she was feeling better but barely able to walk.
Maegan, right, suffers with chronic inflammatory demyelinating polyneuropathy (CIDP), a disease that causes the immune system to mistakenly attack the nervous system
Claire remembers this time and the impact on her family.
Her father Steve, a clinical psychologist, began to frantically research Maegan’s symptoms.
Their elder sister Rachael, then aged nine, was old enough to grasp how serious and worrying things were.
But her parents somehow managed to keep the household running, with her nearby relatives pitching in to help when needed.
Still, the strain was real.
‘I felt a huge burden of guilt at being “the healthy twin”,’ reflects Claire. ‘In a way, my childhood was robbed from me, too – I spent so much of it in and out of hospitals with Maegan, watching her nearly die.’ Within a month of her hospital discharge, Maegan deteriorated – she was in a wheelchair, her legs fully paralysed, and her arms so weak she couldn’t hold herself up.
Claire says: ‘I remember her screaming and crying at night if she needed my parents to help her turn over in bed when she became so weak. By this stage, I knew something really bad was going on.
‘That was a really low point. Maegan looked emaciated, her legs visibly wasting away. She looked like she was dying.’
Claire has become a neuroscientist at the University of Oxford and has discovered a type of antibody that seems to play a role in CIDP and could be a target for new treatments
Then one night – within two months of her collapse at school – her parents had to make an emergency dash with Maegan to the Mayo Clinic, after doctors said her lungs were at risk of failing. It was then that Maegan’s family finally discovered what was wrong with her: chronic inflammatory demyelinating polyneuropathy (CIDP).
This is one of a group of autoimmune neurological conditions – or inflammatory neuropathies – where the immune system mistakenly attacks the nervous system.
Maegan’s white blood cells and antibodies had been stripping the protective covering (called myelin) around the peripheral nerves, which control muscles and communicate sensations.
This impaired their ability to carry signals to and from the brain and spinal cord – and explained why she experienced both muscle weakness and severe pain.
CIDP affects around 5,000 people in the UK, with up to 650 people diagnosed each year – and there is no cure.
‘Symptoms often begin gradually, but characteristically continue to worsen over weeks to months,’ says world-leading expert, Simon Rinaldi, a professor of neurology at the University of Oxford.
‘People may notice persistent pins and needles or numbness in their hands or feet, weakness in their arms or legs, problems with balance or increasing difficulty walking.’
He adds: ‘Tingling and numbness are common symptoms and are usually caused by something much less serious. The pattern that concerns us is when several symptoms occur together, get worse and interfere with everyday activities such as climbing stairs, walking or carrying shopping.’
Without treatment, ongoing inflammation can lead to permanent nerve damage and lasting disability, but CIDP can be treated, he explains.
‘The main treatments include steroids, intravenous immunoglobulin – an infusion of antibodies purified from the blood of thousands of blood donors – and plasma exchange, filtering the patient’s blood to remove harmful antibodies and other disease-causing factors.
‘Many patients regain strength, improve their mobility and are able to continue living independently,’ says Professor Rinaldi.
But while current treatments can help, they are not a cure, and they don’t work for everyone – some people can recover fully, whereas others will require long-term treatment and remain significantly disabled.
After weekly intravenous immunoglobulin, Maegan was eventually able to return home.
But it took time to build her strength – it was three years before she was out of a wheelchair and able to walk with the assistance of a walking frame.
Her sister’s ordeal made Claire determined to become a scientist so she could help in some way.
And now, in an extraordinary development, Claire has managed to do just that – discovering a type of antibody, known as IgM that seems to play a role in CIDP – and could be a target for new treatments.
Working alone in the lab on a Friday evening in September 2024, she applied these newly discovered antibodies to cell cultures and looked under the microscope. What she saw changed everything.
It was a moment she’d serendipitously captured on video, in a deeply emotional moment.
‘For many years, patients with CIDP were treated with the same range of therapies but some responded poorly or not at all,’ explains Professor Rinaldi, who is also Claire’s research mentor.
‘The discovery that harmful IgG antibodies drive disease in some CIDP patients revolutionised treatment, leading to targeted therapies that have changed practice around the world.
‘Now Claire has identified the role of a different type of antibody, IgM, in a closely related nerve disease.
‘She is investigating whether IgM may also play a role in patients with CIDP; this could ultimately improve the way these rare nerve diseases are diagnosed and treated.’
For Claire, the path to this has not been easy.
After studying neuroscience, she applied to do a PhD, but was rejected by all 11 US programmes she had approached (essentially because she didn’t know how the system worked).
After a stint in biotech research throughout the Covid pandemic, she reapplied in the US. But again she was rejected.
However, refusing to give up, Claire applied to both Oxford and Cambridge universities in 2021 – and received scholarship offers from both.
Choosing Oxford, she undertook a doctorate to investigate a rare nerve disease that presents with CIDP-like symptoms.
She spent nearly three years glued to a laboratory searching for an antibody called IgG, a driver of CIDP, but found nothing.
‘I felt like a failure, like there was something I was doing wrong,’ says Claire.
But instead of giving up, she pivoted to testing a different suspect that no one had previously considered – IgM antibodies, a different, bigger class of antibody which have been known to drive other inflammatory neuropathies.
That’s when her moment of discovery occurred.
‘When I looked into the microscope the IgM antibodies were “fluorescing” with incredible brightness – this indicated that they were locking on to the nerve targets and they were doing it far more strongly than anything I’d previously studied,’ she explains.
‘This finding suggests that these antibodies could be causing disease, and that might also be the case in CIDP, too.
‘It was also a very emotional moment. I fell to the floor – like, on my hands and knees – because I just couldn’t believe it,’ she recalls.
‘A lot of what was behind that emotion was just how long I’d been looking for a positive result. It felt validating and I couldn’t wait to tell Maegan.
‘I texted her immediately. She replied “I AM SO SO SO SO SO SO PSYCHED FOR YOU”.’
Since completing her PhD in June last year, Claire has founded the Oxbridge Admissions Club, helping people from all walks of life access the UK’s top universities – she also now works at Oxford as a neuroscientist continuing her research.
Just months ago, using the same antibody screening approach, she discovered the IgM antibodies not just in cells but in some CIDP patients, too.
Claire says: ‘The thread from my work to my sister’s disease is real and active; for me, it’s the direction of the whole project.’ Today, Maegan is in remission and no longer requires any treatment. She is able to walk unaided and works as a software engineer – ‘she is incredibly clever’, says Claire – and in autumn 2024, she got married.
But the disease has taken its toll. Maegan suffers from extreme stomach pain occasionally, sometimes requiring A&E visits; foot drop, which makes walking or running more difficult; and fatigue.
‘Everything is five times harder for her than for me,’ explains Claire. ‘This is down to the disease not being caught early enough.’ Rare diseases such as CIDP are often neglected when it comes to developing new treatments, because the medical system is structured around conditions that affect larger numbers of people – indeed, Claire’s research has been supported by the charities Inflammatory Neuropathies UK and GBS-CIDP Foundation International.
And the future is encouraging, says Professor Rinaldi: ‘For three decades, treatment options for CIDP changed very little, but a new treatment has recently been approved that targets one of the immune pathways thought to contribute to the disease. We’re also learning much more about why CIDP develops and why different patients respond differently to treatment.
‘Researchers are beginning to connect the dots between related autoimmune nerve diseases, with discoveries in one condition helping us better understand another.’
Claire remains focused on the prize: ‘I went into research determined to help find a cure for the disease my sister lives with, and that genuinely drives me.’
