TOP1 and pemphigus foliaceus: Besides, disrupted LDL–LDLR expression was also observed in other three mouse PF models, including BLM‐induced SSc‐PF, DNA Topoisomerase I, Complete Freund's Adjuvant (TopoI‐CFA)‐induced PF and graft‐versus‐host disease (GVHD)‐induced PF (Supporting information Figure S5).