Correlating with our HDAC activity assays (Fig. 5b, c), we detected inactive (AcK) HDAC1 and (PhS) HDAC2 in fractions 8 and 9 of IPF nuclear extracts, but not in fractions 5 and 6 of Ctrl nuclear extracts. Here, HDAC1 is linked to idiopathic pulmonary fibrosis.