PTPRC and idiopathic pulmonary fibrosis: ROIs analyzed were fibroblastic foci (IPF-FF, n = 10) and their adjacent alveolar septae (IPF-AAS, n = 10), nearby immune infiltrates identified by CD45+ staining (IPF-IM, n = 6), morphologically preserved alveolar septae distant from fibroblastic foci (IPF-DAS, n = 10), and blood vessel walls containing smooth muscle (IPF-BV, n = 6) (Figures 1B–1E).