Furthermore, CXXC5 impedes mouse lung fibroblast (MLF) proliferation and transformation to myofibroblasts by inhibiting activation of the CD40/CD40L pathway and promotes apoptosis of MLFs, and CXXC5 overexpression has been discovered to inhibit the progression of bleomycin-induced lung fibrosis in mice [56]. Here, CD40 is linked to pulmonary fibrosis.