ENPP2 and idiopathic pulmonary fibrosis: LPA is increased in BALFs and exhaled breath condensates in patients with idiopathic pulmonary fibrosis (IPF), and the expression of ATX with lysophospholipase D activity that converts LPC into LPA is increased in lung tissues from patients with IPF and fibrotic non-specific interstitial pneumonia [38] (Figure 3).