Understanding the Risk of Multiple Sclerosis in Patients With HIV

Elaine Kingwell, PhD

A major theme at the 2023 Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum was the role of viruses, specifically Epstein-Barr virus (EBV), and their role in the pathogenesis of multiple sclerosis (MS). Human immunodeficiency virus, or HIV, results in reduced CD4+ T cells, which have been implicated in early stages of MS. Led by Elaine Kingwell, PhD, a study presented at the forum compared the risk of incident MS in an international cohort of HIV-positive individuals to that in the general population. A secondary goal was to assess whether antiretroviral therapy modifies or limits MS disease activity.

The longitudinal cohort study featured individuals from Sweden and British Columbia, Canada, and linked data from HIV-positive cohorts, MS registries, and routinely collected health administrative data. With an average follow-up time of 9-10 years, findings showed a lower risk of MS among HIV-positive individuals than expected. Standardized incidence ratios for incidence MS in the combined cohort of HIV-positive patients were 0.53 (95% CI, 0.32-0.90). By sex, these rates were 0.28 (95% CI, 0.09-0.88) for women with HIV and 0.70 (95% CI, 0.39-1.27) for HIV-positive men.

Following the presentation, NeurologyLive^® reached out to Kingwell to gain a better understanding of the implications of these findings and how they translate to clinical care. Kingwell, a senior research associate in the Institute of Epidemiology and Health at University College London, answered questions regarding the connection between MS and HIV, the role of antiretroviral therapy, and where research may turn to next.

What are your greatest take-home points from the study the clinical should be aware of?

People with HIV, or people with HIV who were treated with anti-retroviral therapy (ART), had a lower risk of MS than seen in the general population. We compared the risk of being diagnosed with MS in the HIV population to the risk in people in the general population while accounting for age, sex, calendar year, socioeconomic status and country of birth. The risk of MS was about 50% lower for people with HIV and for people who had been treated with ART. These findings suggest that HIV and/or ART treatment could be protective against MS.

What can we learn about the connection between MS and HIV? How do these findings extend our knowledge?

This was an international observational study accessing linked data from HIV+ cohorts, MS registries and routinely collected health administrative data. We followed more than 29,000 people with HIV in Canada and Sweden for up to 28 years to measure their risk of MS and calculated the expected risk of MS from over 6 million people in the general populations. A lower risk of MS than expected was seen in both the Canadian and Swedish HIV cohorts; these findings are also consistent with earlier reports of a lower MS risk from English and Danish HIV populations.

Are there neuroprotective aspects of HIV that we’re unsure of currently?

As more than 85% of the people in the HIV cohorts were treated with ART, we cannot separate the potential protective effect to HIV or ART. Interestingly though, the findings following ART treatment imply that there is a lower risk of MS even when the HIV virus is suppressed by ART.

If you were to extend this data even further, are there any subgroups of patients you’d observe closely?

In both Canada and Sweden, the risk of MS was lower for men and for women with HIV but the reduced risk was more pronounced for women. Further research could explore whether there is a true sex difference and possible reasons or mechanisms.

What is the significance in increased research towards the connection between MS and viral infections?

The findings provide support for further exploration of the relationship between ART and MS.