TSLP and rheumatoid arthritis: Moreover, upon TLR activation, IECs produce crucial cytokines and chemokines that orchestrate immune responses, such as chemokine (C-C motif) ligand (CCL) 25, CCL28, a proliferation-inducing ligand (APRIL), B cell-activating factor (BAFF), IL-25, RA, TGF-β as well as thymic stromal lymphopoietin (TSLP) (34, 35).