The world around me began to spin, and the dizziness became unbearable. I collapsed.

It was the start of my lengthy journey to a diagnosis of multiple sclerosis, and last year, a stem cell transplant for my MS.
My last major relapse in 2016 – with a lesion on the brain stem – left me unable to walk properly, constantly dizzy, with double vision, nerve damage to the eyes, problems with proprioception, and tinnitus.

I could no longer find words quickly, think 
or speak clearly. Those cognitive problems meant giving up the job I loved as a specialist BBC correspondent.

At 49, I was facing a level of disability that threatened to take away my independence as well as my livelihood.
Then I saw a Panorama programme made by my colleague Fergus Walsh about medical trials using stem cell transplants (HSCT) for MS.

The initial trials were aimed at showing that MS patients could safely undergo chemotherapy followed by a stem cell transplant using the patient’s own cells, the building blocks of the immune system.

It’s known as a non-myeloablative autologous haematopoietic stem cell transplant, HSCT, first performed for MS patients in the 1990s.

I contacted the Royal Hallamshire Hospital in Sheffield, where neurologist Professor Basil Sharrack and haematologist Dr John Snowden were leading the UK arm of the trials.
They were kind enough to perform the tests for inclusion, but I didn’t qualify under the trial’s strict criteria.

One of the key tests 
was an MRI brain scan, which must show active and inflammatory lesions. My initial scan didn’t, suggesting I wouldn’t be a good candidate for a stem cell transplant.

I was aware that there was a small but significant chance of death during HSCT from infection or other complications during or after chemotherapy, though it is now well under one per cent when HSCT is performed at reputable specialist centres.

That made my decision to go abroad for treatment a 
tough one.
Such a risk is deemed acceptable in cancer treatment, but many doctors remain cautious about recommending HSCT for those with a chronic illness such as MS.

Nonetheless, NHS England does now perform HSCT for MS in London at hospitals including Kings College, Charing Cross and University College Hospital.

It’s offered privately in England too. However, I doubted that I would be accepted for treatment here, as the criteria were the same as the trials.

For me, time was running out: I was on the cusp of secondary progressive MS. By the end of 2016, I felt that the disease was killing me – just more slowly and less visibly than cancer.

So on January 1st 2017, I began treatment at Clinica Ruiz in Puebla in Mexico, a private haematology clinic that has safely treated hundreds of international MS patients
with HSCT.

Clinica Ruiz offered outpatient treatment, with an apartment for each patient to live in with a carer. That meant that
during the neutropenic phase after chemotherapy, when the immune system was severely compromised, I could control my environment more effectively than in hospital.

I also decided to pay for a fully qualified nurse to live with me for the 28 days of treatment.

Medical tests to ensure that everyone in our group of 20 international patients was fit for transplant took up the initial day.

First came a spirometry test for lung function, then an electrocardiogram for heart function, as well as a full brain and spinal MRI to ensure there were no signs of any undiagnosed problems. Then came a wealth of blood tests, and consultations with a neurologist and a cardiologist.

On the second day, we sat in comfy armchairs at the clinic as the cyclophosphamide chemotherapy agent dripped slowly into our veins through a cannula.
I was ill during the four days of chemotherapy, despite the anti-nausea drugs.

Each morning, a doctor or nurse would administer an injection of filgrastim, the mobilising agent that would encourage the stem cells from
our bone marrow ahead of the stem cell harvest. Along with breakfast every day came six tablets, from anti-virals to antibiotics and steroids.

Remarkably, despite the nausea during and after those chemotherapy sessions, my brain fog began to life. I could read and remember again. No longer did I awake to crippling migraines, while the nerve pain in my fingers and toes eased.

Even the heaviness in my legs and arms diminished. My energy levels rose, though steroids and sleep probably helped.

However, something in my brain and body had definitely shifted. I woke up in the morning feeling well-rested for the first
time in many years, with no neurological fatigue whatsoever.

I was heavily sedated during the insertion of
a central venous line into my chest. For four days, it would help ease the passage of blood from my veins on stem cell harvest day, and during the stem cells’ return a few days later.

On stem cell harvest day itself I woke up feeling nervous. During the four hours of apheresis, the stem cell harvest, the clinic recommended nappies, as continence is a problem for many patients with MS.

After the harvest came our penultimate chemotherapy session, with patients hooked up to the chemo infusion for around three to four hours.

My stem cell ‘birthday’ dawned bright and sunny on Saturday January 14th 2017.

It took just one hour to receive my own stem cells back, which would shorten the time spent in neutropenia and help spark the growth of my new immune system. The cells seeping into my veins felt like a rebirth.

For the next ten days, I was monitored for neutropenia, while the cleaner sanitised 
the apartment each day, to help me avoid infection.

The final infusion was a dose of Rituximab, a monoclonal antibody that targets a protein called CD20 that is found on the surface of white blood cells called B-lymphocytes or B-cells. It is aimed at depleting any remaining lymphocytes following chemotherapy.

By the time I arrived home on January 29th, I was almost bald, a small price to pay if
it meant I could grow a new, functioning immune system.

However, the recovery period has proved harder than the transplant. Chemotherapy is an aggressive treatment, with many after-effects, one reason why the NHS discourages patients from seeking such serious medical treatment abroad – not least because it has a duty of care to help if anything goes wrong.

For the first weeks back at home, in quarantine, I slept a lot as I came down from my steroid high. The second week brought some improvements to my balance, while by the third, I was able to walk further and more easily, albeit with a walking stick.

After a few months, I was able to start stretching exercises at home, and noticed that the blurriness in my left eye was receding, although my brain and limbs still felt wobbly.

But the following months proved more challenging.

Sleep was often elusive, as I lay shivering in a cold sweat or wide-awake with hot flushes. Chemotherapy has a major impact on hormones, and a majority of HSCT patients over the age of 32 will be left infertile – a major consideration for younger patients.

Then the migraines returned, along with painful stiffness, spasms and numbness in my limbs, plus peripheral neuropathy in my hands and feet.

Recovery from a stem cell transplant for MS is a rollercoaster ride, even one year on.
I often feel worse than I did before HSCT and still need to rest frequently during the day. When I work, I have no energy left for anything else. But there are days when I feel a little better, and my hopes soar. Of the other HSCT patients I know, some have seen major improvements. They are overjoyed that they can again play a full part in family life, or work without exhaustion.

Many train hard at the gym or at home, trying to regain limb function and balance. Some receive excellent neuro-rehabilitation, though many have to pay privately.
Others report little change.

A few say they now feel worse than they did before HSCT, and wish they had never had the treatment.

Much about the long-term impact of HSCT on auto-immune diseases is still unknown, and may remain unclear until the causes of these diseases are better understood.

Soberingly some HSCT patients at international centres have died over the past year. It is not a treatment to be entered into lightly, however effective it can be in halting progression for some.

Many patients have struggled after transplant with everything from migraines, headaches, swollen feet or agonising neuropathic pain in the hands and feet, to bacterial infections that affect the bladder, as well as common viral infections that resurface in the body when the immune system is fragile, such as the Epstein-Barr virus, herpes and shingles.

My latest MRI brain scan shows that so far, I have no new lesions. I hope that I shall be among the lucky ones whose MS progression is halted for several years, so I can enjoy life – and spend time with my family and friends, and continue to work and be useful to others.

I can’t, as yet, repair all the damage done 
to my brain and central nervous system
by over two decades of MS. But I am an optimist. I hope that when my immune system reconstitutes itself fully by the end of 2018, it will be able to deal normally with whatever first triggered my MS.

In over 25 years with the BBC, Caroline Wyatt has been a foreign, defence and religious affairs correspondent. As well as postings in Germany, Russia and France, she has reported from across Europe, the Middle East, Asia and Africa. In 2016, she stepped down from her role as a correspondent after being diagnosed with multiple sclerosis, but continues to work as a journalist and presenter.

All content in this article, including pictures, is the copyright of Caroline Wyatt.