Peripheral blood non-MAIT CD8+CD161hi cells are decreased in relapsing-remitting multiple sclerosis patients treated with interferon beta.

CD8+CD161hi cells, comprising MAIT and non-MAIT cells, have been involved in multiple sclerosis (MS) pathogenesis. Here, we investigated the frequency of CD8+CD161hi, MAIT and non-MAIT cells by flow cytometry in peripheral blood samples from 41 untreated MS patients, 48 patients receiving disease modifying therapies, and 17 healthy controls (HC). IFNβ treatment was associated with a decrease in the frequency of Tc17 cells compared to untreated patients (p=0.019). No significant differences were observed between untreated MS patients and HC for any of the study cell populations. These results suggest previously unknown mechanisms of action of IFNβ.