THY1 and idiopathic pulmonary fibrosis: Human IPF LSCs, expanded from an IPF fibrotic lung, express cluster of differentiation 90 (CD90) (86.1%), cluster of differentiation CD105 (82.2%), surfactant protein C (SFTPC) (41.7%), club cell secretory protein (CCSP) (79.2%), and aquaporin 5 (AQP 5) (71.2%), as verified by flow cytometry (Figure 3E).