Background and objective PPFE is characterized by fibrosis in the pleura and subpleural lung parenchyma in the upper lobes, while other types of ILD, mainly UIP, can be observed in about half of the patients in their lower lobes. The aim of this study was to evaluate the clinical significance of the radiologically defined PPFE in patients with IPF. Methods Clinical data and chest CT images were retrospectively analysed in 445 patients with IPF (biopsy‐proven cases, n = 165). The radiological criteria of PPFE were defined as follows: (i) bilateral subpleural dense fibrosis with or without pleural thickening in the upper lobes, (ii) evidence of disease progression and (iii) no clinical evidence of identifiable aetiologies. Results The median follow‐up period was 43.0 months. The mean age of the patients was 66.4 years and 76.4% were male. PPFE was identified in 28 patients (6.3%). The PPFE group showed lower BMI and lung function (FVC and TLC) at baseline, more frequent pneumothorax and pneumomediastinum, higher decline rates in lung function and poorer prognosis during follow‐up than the no‐PPFE group. PPFE was an independent risk factor (HR = 2.953, 95% CI: 1.350–6.460, P = 0.007) for pneumothorax or pneumomediastinum, but not for mortality in patients with IPF. Conclusion Among patients with IPF, the PPFE group, when compared to the no‐PPFE group, showed lower BMI and lung function and showed more frequent complications and poorer survival during follow‐up.

Background Immune checkpoint inhibitors (ICIs) have become the standard of care for a variety of cancers, including non-small cell lung cancer (NSCLC). In this study, we investigated the frequency of pseudoprogression and hyperprogression in lung cancer patients treated with ICIs in the real world and aimed to discover a novel candidate marker to distinguish pseudoprogression from hyperprogression soon after ICI treatment. Methods This study included 74 patients with advanced NSCLC who were treated with PD-1/PD-L1 inhibitors at Chungnam National University Hospital (CNUH) between January 2018 and August 2020. Chest X-rays were examined on day 7 after the first ICI dose to identify changes in the primary mass, and the response was assessed by computed tomography (CT). We evaluated circulating regulatory T (Treg) cells using flow cytometry and correlated the findings with clinical outcomes. Results The incidence of pseudoprogression was 13.5%, and that of hyperprogression was 8.1%. On day 7 after initiation of treatment, the frequency of CD4+CD25+CD127loFoxP3+ Treg cells was significantly decreased compared with baseline (P = 0.038) in patients who experienced pseudoprogression and significantly increased compared with baseline (P = 0.024) in patients who experienced hyperprogression. In the responder group, the frequencies of CD4+CD25+CD127loFoxP3+ Treg cells and PD-1+CD4+CD25+CD127loFoxP3+ Treg cells were significantly decreased 7 days after commencement of treatment compared with baseline (P = 0.034 and P < 0.001, respectively). Conclusion Circulating Treg cells represent a promising potential dynamic biomarker to predict efficacy and differentiate atypical responses, including pseudoprogression and hyperprogression, after immunotherapy in patients with NSCLC.