There was a striking increase in IGFBP-1 and −2 in the group of untreated IPF patients compared to healthy subjects (respectively p < 0.05, p < 0.0001) (Figs. 2–3), while untreated IPF showed a significant decrease in serum IGF-1 (p < 0.05), IGF-2 (p < 0.01) and IGFBP-3 (p < 0.01). Here, IGF2 is linked to idiopathic pulmonary fibrosis.