Children in group B were characterized by higher levels of Thy-1 membrane glycoprotein (THY1), also known as CD90, and lower levels of angiopoietin-related protein 2 (ANGPTL2) than those in groups A and C. The role of THY1 is as a glycophosphatidylinositol anchored cell surface glycoprotein [21,22], and it has been recently characterized to be a key regulator of the WNT pathway, attenuating interstitial pulmonary fibrosis and promoting lung fibroblast apoptosis [23]. This evidence concerns the gene THY1 and pulmonary fibrosis.