HIV Or Anti-HIV Drugs Unexpectedly Protect Against Multiple Sclerosis, Otherwise A Disease With No Therapy
A team of an Australian doctor and British researchers analyzed the medical records of over 5 million individuals and discovered that either HIV or anti-HIV drugs have a protective effect against multiple sclerosis (MS). AIDS patients or people with HIV receiving treatment have a 60% less likely chance of receiving a diagnosis of MS. Deeper analysis found that those on a treatment regimen the longest, for 5 years or more, had an 80% reduced chance of developing MS. The discovery is remarkable for the fact that no curative or preventative treatments for MS exist and this unexpected insight may be one of the most interesting avenues.
The researchers write
“If subsequent studies demonstrate there is a causal protective effect of HIV (and/or its treatment), and if the magnitude of it proves to be similar…this would be the largest protective effect of any factor yet observed in relation to the development of MS,”
The primary author of the study, Dr. Julian Gold of Prince of Wales Hospital in Australia, first observed casually that even though he treats patients with HIV and knows people with MS, he had never met a person with both. He searched through medical literature, and found 700,000 studies on HIV/AIDS and 300,000 studies on MS. Out of the approximately 1,000,000 studies, there was no reference to a patient who had both. Eventually, he did find one person whose symptoms of MS began to diminish when he began treatment for HIV.
As a result of this finding, a Danish research team looked at 5,000 people diagnosed with HIV and 50,000 without, but the sample size was too small that the negative connection did not warrant any statistically significance. Instead, Dr. Gold and his team moved onto the English Hospital Episode Statistics, a record of residents of England who had hospital stays. They looked at everyone who had been in the hospital between 1999 and 2011. There were 21,207 patients with HIV and compared those with 5,298,496 uninfected individuals.
Based on the frequency of MS diagnoses in the control group, they calculated that there should have been 18 HIV infected patients with a diagnosis of MS. Instead, they found only seven. Because the population pool was so large, this was a statistically significant finding and suggested that HIV/AIDS patients who receive treatment are 60% less likely to be diagnosed with MS. Segmentation of the population into a group that had been receiving treatment for at least five years found that they were 80% less likely to develop the disease.
It is unclear yet whether the suppression of MS symptoms is due to the infection or the treatment, but either seems reasonable. MS is characterized by symptoms ranging from clumsiness to paralysis to depression. The symptoms are caused by the immune system attacking the central nervous system, specifically the tissue that insulates and protects the nerves. HIV strongly interferes with the immune system, as the virus takes up residence in latent pool inside immune cells. It does not seem implausible that it affects pathways employing or employed by MS, which would explain how the disease could suppress MS. So even though the etiology of MS remains unclear, antivirals used to treat HIV could also be repurposed to treat MS as well.
If it is indeed the antivirals that are suppressing MS, it could mean that treating MS is as simple as approving a few drugs for new uses, obviating lengthy safety trials. If it is the HIV that is conferring protection, treatment is more complicated as investigators would need to seek which aspects of HIV confer protection. Regardless, this is an important result the came from simple, if unexpected, observation.
The research was published on Aug 4, 2014 in the Journal of Neurology, Neurosurgery and Psychiatry.
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