Several studies of idiopathic pulmonary fibrosis (IPF) [8] and rheumatoid arthritis [23] suggested a correlation between IGFBP5 and TGF-β in fibrosis and autoimmune disease, but the precise interaction between IGFBP5 and TGF-β is still unclear. The gene discussed is IGFBP5; the disease is pulmonary fibrosis.