In IPF and cHP, FN expression was also observed in fibroblastic foci, and this staining was more intensive in the subepithelial region, following a similar distribution to TNC (Figure 4A and 4C).In saHP lungs, where no FFs were present, few and specific areas of these glycoproteins were observed; TNC and FN were only localized in the largest lymphocytic aggregates with a reticular pattern. The gene discussed is FN1; the disease is idiopathic pulmonary fibrosis.