BALF from patients with IPF contained significantly more CD61+ platelets in BALF (Fig. 7, A and B) and elevated MMP7 and active TGFβ1, but not total TGFβ1 or CXCL4 concentrations compared with non-ILD controls (Fig. 7, C–F). Here, PF4 is linked to idiopathic pulmonary fibrosis.