April 2021
A group of helper T-cell (Th cells), a type of immune cell, could be responsible for the transition from relapsing-remitting multiple sclerosis (RRMS) to secondary progressive multiple sclerosis (SPMS), with important implications for diagnosing and treating SPMS, a new study found.
The study, “Involvement of cytotoxic Eomes-expressing CD4+ T cells in secondary progressive multiple sclerosis,” was published in the journal PNAS by a team of researchers from the National Center of Neurology and Psychiatry in Tokyo.
SPMS is established as a stage of multiple sclerosis that follows RRMS, but the mechanisms driving the transition are not well understood, and progression is difficult to predict.
Recently, however, scientists linked the transition to processes mediated by immune-regulating T-cells.
“Understanding the role of T-cells in SPMS development could lead to the identification of key cellular and molecular components that may serve as potential therapeutic targets or useful biomarkers,” the researchers wrote.
In a previous study in mice, this team identified a subset of Th cells (also called CD4+ T-cells) that was crucial for chronic inflammation of the central nervous system. That particular subset of Th cells expressed the transcription factor Eomes (Eomes+ Th cells). Transcription factors are proteins that bind to DNA to regulate the process by which information in a gene is ultimately converted into a protein.
Now, the team investigated whether Eomes+ Th cells also play a role in human disease.
Their study included 39 people with RRMS, 25 with primary progressive multiple sclerosis (PPMS), 66 patients with SPMS, and 42 healthy individuals.
First, the researchers looked at Eomes+ Th cells in peripheral blood samples. They found the proportion of Eomes+ Th cells among the CD4+ T-cell population to be higher in SPMS patients, compared with healthy individuals or those with RRMS and PPMS. An increase in Eomes+ Th cells was seen in more than half of the SPMS group, but only in a few patients with RRMS, one PPMS patient, and one healthy individual.
“These results indicate a significant link of Eomes+ Th cells with SPMS,” the researchers wrote.
Next, the team applied a mathematical model that divided SPMS patients into two groups according to their proportion of Eomes+ Th cells: high or low. A high proportion of Eomes+ Th cells was found to be linked to disability progression in these people.