INPP4A and pemphigus foliaceus: The observation that intraperitoneal treatment with anti‐INPP4A antibody increased subepithelial fibroblast proliferation and collagen deposition in both naïve mice and mice with AAI provided a strong rationale to investigate the role of INPP4A in the pathogenesis of pulmonary fibrosis (PF) (Khanna et al., 2019).