IGFBP5 and pulmonary fibrosis: In lung tissue from patients with idiopathic pulmonary fibrosis, IGFBP5 was upregulated and exogenous IGFBP5 stimulated extracellular matrix secretion by idiopathic pulmonary fibrosis pulmonary fibroblasts.33, 34 Furthermore, IGFBP5 was upregulated in skin fibroblasts from patients with systemic sclerosis.35