ObjectiveTo investigate the role of Krüppel-like factor 4 (KLF4) mediated monocyte/macrophage subtype switch in the pathological progression of pulmonary fibrosis.MethodsThirty-six patients with interstitial pneumonia were recruited from Characteristic Medical Center of the Chinese People's Armed Police Force between May 2015 and January 2017. Peripheral venous blood and bronchoalveolar lavage fluid were collected in the morning. Pulmonary function and arterial blood gas were tested after admission. Flow cytometry was used to test monocyte subtypes of peripheral blood and macrophage subtypes of bronchoalveolar lavage fluid. KLF4 of peripheral blood was detected by enzyme linked immunosorbent assay. Thirty normal subjects were selected as control group of peripheral blood mononuclear cell subtypes and KLF4 (control group A), and 10 patients without pulmonary fibrosis who needed bronchoscopy were selected as control group of macrophage subtypes in alveolar lavage fluid (control group B). The relationship between the expression of KLF4 and the differentiation of monocytes and macrophages were observed. Furthermore, the relationship between the differentiation of monocytes subtypes, macrophages subtypes and lung function were observed.ResultsMonocyte of CD14++CD16– subtype in pulmonary fibrosis group was significantly lower than that in control group A (P<0.05). Monocyte of CD14++CD16+ subtype in pulmonary fibrosis group was significantly higher than that in control group A (P<0.05). No significant difference was found between the two groups regarding CD14+CD16++. No correlation was found between three subtypes of monocyte and DLCO of patients and between three subtypes of monocyte and PaO2 of patients. M1 macrophage in pulmonary fibrosis group was significantly lower than that in control group B (P<0.05). M2 macrophage in pulmonary fibrosis group was significantly higher than that in control group B (P<0.05). Negative correlation was found between the ratio of M2 subtypes and DLCO of patients and between the ratio of M2 subtypes and PaO2 of patients (P<0.05). KLF4 protein of blood in pulmonary fibrosis group was significantly higher than that in control group A (P<0.05). Positive correlation was found between the ratio of M2 subtypes and KLF4 protein (P<0.05).ConclusionsCD16+ monocyte plays a role in the occurrence and development of pulmonary fibrosis, but no evidence is found there is a direct correlation between monocyte subtypes of peripheral blood and fibrosis degree of lung tissue. M2 macrophage subtype plays an important role in the development of interstitial pneumonia. The number of M2 macrophages is positively correlated with the severity of pulmonary fibrosis. Monocyte/macrophage subtype differentiation by KLF4 may play a role in the pathological progression of pulmonary fibrosis.
Objective To investigate the characteristics on chest high-resolution computed tomography (HRCT) of patients with interstitial pneumonia with positive myeloperoxidase antineutrophil cytoplasmic antibody (MPO-IP). Methods The extent of fibrosis and subtypes of emphysema on HRCT of MPO-IP patients were retrospectively analyzed and compared with idiopathic pulmonary fibrosis (IPF) cases admitted in the same period. Results From July 2014 to March 2016, 10 patients was diagnosed with IPF and 10 patients was diagnosed with MPO-IP. Emphysema was not different between two groups. Among the MPO-IP patients, 8 patients presented with a usual interstitial pneumonia (UIP) pattern. There existed statistical difference in the bronchial bifurcation level, the fibrosis score of lungs in the MPO-IP patients presented with UIP was lower than that in the IPF patients. Conclusions UIP is the predominant radiologic type of MPO-IP patients. Fibrosis in IPF is more serious than that in MPO-IP with UIP. Paraseptal and centrilobular emphysema are main forms in MPO-IP patients.