Tofacitinib Suppresses Several JAK-STAT Pathways in Rheumatoid Arthritis In Vivo and Baseline Signaling Profile Associates With Treatment Response

Abstract

Tofacitinib suppresses multiple JAK-STAT pathways in cytokine and cell population specific manner in RA patients <i>in vivo</i>. Besides directly inhibiting JAK activation, tofacitinib downregulates the expression of JAK-STAT pathway components. This may modulate the effects of tofacitinib on JAK-STAT pathway activation <i>in vivo</i> and explain some of the differential findings between the current study and previous <i>in vitro</i> studies. Finally, baseline immunological markers associate with the treatment response to tofacitinib.