Shana Pezaro, 36, from Hove, East Sussex, was given antiretroviral drugs after fearing she may have contracted HIV.
Within days, Miss Pezaro noticed an easing of her MS symptoms.
When a doctor saw her walking up stairs after years of using a wheelchair he set up a clinical trial.
Multiple sclerosis is an incurable condition that can lead to sight loss, pain, fatigue and disability. It affects around 100,000 people in the UK.
Miss Pezaro was a dancer and piano teacher before being diagnosed with MS at the age of 28. The condition affected her hands and feet and she used a wheelchair.
In MS the coating around the nerve fibres is damaged causing a range of symptoms
Once diagnosed there is no cure, but treatments can help manage the condition
MS affects almost three times as many women as men
Physical symptoms of MS might commonly include vision problems, balance problems and dizziness, fatigue, bladder problems and stiffness and/or spasms
MS can affect memory and thinking and also can have an impact on emotions
About a year ago, Miss Pezaro thought she may have been exposed to HIV and her doctor prescribed emergency antiretroviral drugs.
“Three days after I took the drugs I walked up a flight of stairs,” she said.
“That was an unbelievable, massive change.
Prof Julian Gold from the Prince of Wales Hospital in Sydney, saw a video of Miss Pezaro climbing the stairs and a clinical trial was set up to look at the impact of single or combination antiretroviral drugs on MS patients.
Full story on BBC website.