Background: Multiple sclerosis (MS) patients are at risk of renewed disease activity after discontinuing natalizumab (NAT) treatment.
Objective: Assessing the implication of T helper 17 (Th17) cells in MS reactivation after NAT cessation.
Methods: We monitored frequencies of Th17 cells and interleukin (IL)-17 cytokine levels in blood samples of 57 MS patients, without, during, and after NAT exposure.
Results: Frequencies of both Th17 cells and, in part, also IL-17 levels, in peripheral blood increased under prolonged NAT therapy, returned to baseline after NAT withdrawal and became almost undetectable in blood samples of individuals who experienced relapses during the wash-out phase.
Conclusion: Assessing the Th17-cell/IL-17 axis might help to predict rebound MS activity after NAT withdrawal.
Keywords: Multiple sclerosis; Th17 effector T cells; natalizumab; rebound effect; wash-out phase.