TGFB1 and pemphigus foliaceus: Recent investigations have demonstrated that TGF‐β1 (transforming growth factor β1) and its receptor TGF‐βRI (TGF‐β receptor I) promoted the transformation of pericytes into myofibroblasts during PF pathogenesis, mediated by the activation of Smad2/3 (Sma and Mad homologue 2/3) signalling pathway.7