Low dose CP-690,550 (tofacitinib), a pan-JAK inhibitor, accelerates the onset of experimental autoimmune encephalomyelitis by potentiating Th17 differentiation

► Low dose CP-690,550 (tofacitinib) inhibited CIA but accelerated EAE models. ► Low dose CP-690550 inhibited Th1 and Th2 but enhanced Th17 development. ► Low dose CP-690,550 inhibited STAT1,5,6 but not STAT3 phosphorylation. ► CP-690,550 inhibits JAK1 less efficiently than JAK3 in vivo.