HIV Drugs, Viruses and Multiple Sclerosis
Within several days of taking antiretroviral drugs to address possible HIV exposure, a 36-year-old woman with multiple sclerosis was able to get out of her wheelchair and walk again. This case and associated research highlight the question about the possible association between HIV and multiple sclerosis and the role of viral infections in causing this neurodegenerative disease.
Multiple sclerosis affected the hands and feet of Shana Pezaro of East Sussex, UK, a former dancer and piano teacher, resulting in her need to use a wheelchair. When she thought she might have been exposed to HIV, her doctor prescribed emergency antiretroviral drugs, and three days later she was able to climb stairs.
When Professor Julian Gold, of Prince of Wales Hospital in Sydney, saw a video of Ms. Pezaro’s accomplishment, he established a clinical trial to explore the effects of antiretroviral drugs on individuals who have multiple sclerosis. Dr. Gold had previously conducted research on an association between MS and HIV.
In Dr. Gold’s earlier study, he and his colleagues evaluated medical data from about 21,000 individuals with HIV to discern how many had developed MS. Their findings suggested to them that use of antiretroviral drugs may protect the immune system from developing multiple sclerosis.
In fact, they discovered that individuals with HIV were 62 percent less likely to develop MS than those who did not have the virus. The authors had two theories as to why this may be so:
- Immunodeficiency caused by HIV may prevent an autoimmune response (in which the body attacks itself)
- Use of antiretroviral drugs may suppress the activity of other viruses, such as those some experts have suggested may be a cause of MS
Overall, the findings of Dr. Gold’s study indicated that more research should be done on the use of antiretroviral drugs for people who live with multiple sclerosis. In fact, Ms. Pezaro’s case prompted Dr. Gold to explain in a BBC article that “The next stage of the investigation is to use a very similar combination [of HIV drugs] that Shana took. I think that might be quite optimistic.”
Viruses and multiple sclerosis
Thus far, experts have not been able to pin down one or more viruses as being a trigger for multiple sclerosis, although several have been under investigation, including Epstein-Barr and human herpesvirus 6 (HHV-6). As noted by the National Multiple Sclerosis Society, before researchers can state that a specific virus causes the disease, they need to prove
- that the virus is in the body before the disease develops, and
- that the virus really causes MS and is not just co-existing with the disease
Until these criteria are met, researchers will continue their search. Some of those recent efforts include:
- A project by MS Research Australia under direction of David Nolan, an adjunct associate professor at the Institute of Immunology and Infectious Diseases. He and his team were awarded a grant in March 2015 to investigate how Epstein-Barr virus interacts with the immune system in individuals who have MS.
- A recent study published in Trends in Molecular Medicine in which researchers explored the role of cytomegalovirus (a herpesvirus) in multiple sclerosis. So far it appears that the virus may play both a contributing part as well as a protective effect, which makes pinning down a viral cause more challenging.
- A review published in December 2014 by two National Institutes of Health researchers who noted that “the only way to demonstrate the involvement, or lack thereof, of HHV-6 or other herpesviruses in this diseases is through a controlled clinical trial of an efficacious antiviral drug,” which appears to be what Dr. Gold has planned.
The above information barely covers the efforts being made by experts to uncover whether viruses have a role in triggering multiple sclerosis. Research by these and other investigators will hopefully bring us closer to identifying the causes of multiple sclerosis and effective ways to prevent and treat it.
Leibovitch EC, Jacobson S. Evidence linking HHV-6 with multiple sclerosis: an update. Current Opinion in Virology 2014 Dec; 9:127-33
National Multiple Sclerosis Society
Vanheusden M et al. Cytomegalovirus: a culprit or protector in multiple sclerosis? Trends in Molecular Medicine 2015 Jan; 21(1): 16-23