Objective To explore the value of histone deacetylase activity in the diagnosis and management of patients with idiopathic pulmonary fibrosis.Methods Seventy patients with idiopathic pulmonary fibrosis admitted to a hospital in Henan Province from January 2019 to December 2020 were selected as the observation group

while 70 healthy people who underwent health checkups in our hospital during the same period were selected as the control group.The histone deacetylase activity in cytoplasmic and nucleoplasmic proteins of mononuclear cells was compared between the 2 groups;correlation between histone deacetylase activity in cytoplasmic and nucleoplasmic proteins of mononuclear cells and clinical parameters

including forced expiratory volume in the first second（FEV1） as a percentage of the expected value

diffusing capacity for carbon monoxide（DLCO） as a percentage of the expected value

erythrocyte sedimentation rate（ESR）

lactate dehydrogenase（LDH）

ratio of forced expiratory volume in the first second to forced vital capacity（FEV1/FVC）

high-sensitivity C-reactive protein（hs-CRP）

total lung capacity（TLC） as a percentage of the expected value

and expiratory lung volume as a percentage of the expected value

was analyzed.Results Histone deacetylase activity in cytoplasmic and nucleoplasmic proteins of peripheral blood mononuclear cells was higher in the observation group than in the control group

with statistically significant differences（P<0.05）;histone deacetylase activity in nuclear proteins of mononuclear cells was negatively correlated with FEV1 as a percentage of predicted value（r=-0.574

P=0.025） and DLCO as a percentage of predicted value（r=-0.583

P=0.029）.Conclusion Histone deacetylase may play a role in the pathogenesis of idiopathic pulmonary fibrosis

and measurement of histone deacetylase activity using a fluorometric assay may provide a reference for the diagnosis and disease assessment of idiopathic pulmonary fibrosis.