B Cell-Activating Factor Of The Tnf Family Expands Circulating Transitional B Cells In Multiple Sclerosis Patients Treated With Fingolimod

Background: Fingolimod is a sphingosine-1-phosphate receptor agonist used as a disease-modifying drug for multiple sclerosis (MS). We have previously shown that MS patients treated with fingolimod have an increased proportion of circulating transitional B cells, an immunoregulatory B-cell subset, but the underlying mechanism remains unknown. B cell-activating factor of the TNF family (BAFF) is a cytokine involved in the differentiation and proliferation of B cells. Mice overexpressing BAFF have been shown to have increased numbers of transitional B cells.