IL13 and chronic graft versus host disease: Among cytokines and their receptors, TOL patients had decreased expression of IL-13RA (IL-13 induces B cell proliferation and differentiation, and is expressed on Th17 cells), as well as BAFF and APRIL (major B cell activating TNF ligand family members implicated in human chronic GVHD).[34–36] Conversely, TGFBR3 (TGF-β co-receptor relevant to TGF-β receptor complex stability and signaling),[37] expression was increased.