Gut Bacteria and Risk for MS Relapse

In patients with pediatric-onset multiple sclerosis (MS), increased abundance of Blautia stercoris and its variants in the gut is associated with an increased risk of relapse.

No broad differences in gut bacterial composition, however, are associated with risk of relapse, according to the investigators. The findings were presented at the Joint European Committee for Treatment and Research in Multiple Sclerosis-Americas Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS-ACTRIMS) 2020

Although the current study is the largest in patients with MS that includes data about the microbiome and relapses, its findings require replication.

Gut microbes digest food, produce vitamins (for example, B12 and K), create a barrier against pathogens, and regulate the immune system, among other tasks. Most current knowledge about the gut microbiome in MS comes from studies of patients with adult-onset In 2016, Tremlett et al. found an increase in Desulfovibrionaceae and a decrease in Lachnospiraceae and Ruminococcaceae in patients with pediatric-onset They also found that a decrease in Fusobacteria was associated with risk of relapse in this population.

In this new study the investigators recruited 53 patients with pediatric-onset MS from the University of California, San Francisco, and six centers in the U.S. Network of Pediatric MS Centers. At baseline, they collected stool samples, blood samples, information about past relapses, medication records, demographics, and environmental factors. At each relapse, the investigators collected information about the patient's current and past medication use and about relapses that the patient had had since the previous visit.

Gut bacterial abundance was broadly similar between patients who relapsed during the study period and those who did not.

Blautia stercoris had the most significant association with relapse risk (hazard ratio, 2.50).

When Horton and colleagues examined the pathways from these bacterial species associated with the risk of relapse they found pathways that are involved in methane production, which suggests the involvement of methanogenesis pathways in relapse.