Levels of granulocyte colony-stimulation factor, haptoglobin, interferon-γ (IFN.g), interleukin-1rα, interleukin-4 (IL.4), interleukin-7, interleukin-8, macrophage inflammatory protein 1β (chemokine ligand-4), plasminogen activator inhibitor-1, platelet-derived growth factor-bb, and tumor necrosis factor-α were significantly higher in patients with HPS pulmonary fibrosis compared with those with FPF (Figure 4C). Here, IL4 is linked to pulmonary fibrosis.