Avidity of vaccine-induced influenza IgG fails to increase in fingolimod-treated patients with MS

Fingolimod—an efficacious compound for the treatment of relapsing multiple sclerosis (MS)—functionally antagonizes the S1P receptor.1–3 This antagonism inhibits egress of T cells from secondary lymphoid tissues,2 affects B cell migration, and functionally affects germinal center reactions.4 Acknowledgment: The authors thank K. Wild for excellent support with organization of study logistics.