Could Treatments for HIV be Used to Treat MS?
Why is multiple sclerosis so uncommon among people who have HIV (human immunodeficiency virus)? That was the question on Dr. Julian Gold’s mind as he treated his HIV patients. He had a personal interest in MS, and just casually noticed that none of his HIV patients had it. He decided to do some detective work and found that among hundreds of thousands of peer review studies, there was only one reported incidence of the two conditions occurring together. Interestingly, that patient’s MS symptoms disappeared after being on started on HIV treatment, and remained repressed for over 12 years.
Dr. Gold quickly realized he may be on to something, so he and a Danish team of researchers probed the theory by comparing 5,000 people who were HIV positive with a control group of 50,000 HIV negative people. However, that sample size was simply too small to give them good data so they turned to England’s National Health Service’s database. They compared 21,207 HIV positive individuals that were discharged from the hospital between 1999 and 2011, and compared them to a group of 5,298,496 comparable HIV negative individuals. They then used the incidence of MS in the control group to estimate how many individuals in the HIV positive group should have MS if their risk was equal. Based on their calculations, an average of 18 people in the HIV positive group should have MS but only 7 did. In science this is what we joyfully applaud as “statistically significant”. It meant that the HIV positive group was approximately 60% less likely to develop MS. Even further analysis showed that people who had been on antiviral drug therapy for HIV were 80% less likely to develop MS. These results suggest that the drugs used to treat HIV could have a protective effect against MS. The results of this study were published in the Journal of Neurology, Neurosurgery and Psychiatry.
The big question that remains unanswered is why HIV could protect against MS. Right now there are two theories. The first is that it has to do with the immune system. HIV wipes out the immune system, which is what leads to the development of AIDS (acquired immunodeficiency syndrome). In MS patients whose immune system attacks myelin, HIV’s immunosuppressing effects could be why MS is rarely seen in HIV positive people. The second theory is that the treatment of HIV is protecting people from developing MS. One current working theory is that certain viruses may play a role in the development of MS. If MS does have some sort of viral trigger, the antiviral medications given to combat HIV could be acting on a virus that triggers MS. It remains unclear whether it is the infection or the treatment that impacts the incidence of MS.
If it is proven that HIV has a protective effect against MS it would not be the first time in science that one illness protects against another. For example, people with sickle cell anemia are inherently resistant to malaria, and people with Gilbert’s syndrome are protected against ischemic heart disease. The researchers confirm that “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 researchers admit that there are limitations to their current research, including lacking data on patient ethnicity, the exact HIV treatment regimen of each patient, and that the study was purely observational. The next step would be to look more closely at the relationship between antiretroviral HIV treatment, and the development of MS.1-3
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