Our previous studies focusing on Spred2 demonstrated that Spred2 controls the development of lung inflammatory responses by negatively regulating the ERK pathway using an acute lung injury (ALI) model induced by lipopolysaccharide (LPS)19,20, leading us to the hypothesis that Spred2-deficiency may aggravates the development of PF. Here, SPRED2 is linked to pemphigus foliaceus.