BackgroundClinical evaluation to differentiate the characteristic features of pulmonary fibrosis and emphysema is often difficult in patients with combined pulmonary fibrosis and emphysema (CPFE), but diagnosis of pulmonary fibrosis is important for evaluating treatment options and the risk of acute exacerbation of interstitial pneumonia of such patients. As far as we know, it is the first report describing a correlation among clinical, radiological, and whole-lung pathological features in an autopsy cases of CPFE patients.MethodsExperts retrospectively reviewed the clinical charts and examined chest computed tomography (CT) images and pathological findings of an autopsy series of 22 CPFE patients, and compared these with findings from 8 idiopathic pulmonary fibrosis (IPF) patients and 17 emphysema-alone patients.ResultsAll patients had a history of heavy smoking. Forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC%) was significantly lower in the emphysema-alone group than the CPFE and IPF-alone groups. The percent predicted diffusing capacity of the lung for carbon monoxide (DLCO%) was significantly lower in the CPFE group than the IPF- and emphysema-alone groups. Usual interstitial pneumonia (UIP) pattern was observed radiologically in 15 (68.2%) CPFE and 8 (100%) IPF-alone patients and was pathologically observed in all patients from both groups. Pathologically thick-cystic lesions involving one or more acini with dense wall fibrosis and occasional fibroblastic foci surrounded by honeycombing and normal alveoli were confirmed by post-mortem observation as thick-walled cystic lesions (TWCLs). Emphysematous destruction and enlargement of membranous and respiratory bronchioles with fibrosis were observed in the TWCLs. The cystic lesions were always larger than the cysts of honeycombing. The prevalence of both radiological and pathological TWCLs was 72.7% among CPFE patients, but no such lesions were observed in patients with IPF or emphysema alone (p = 0.001). The extent of emphysema in CPFE patients with TWCLs was greater than that in patients without such lesions. Honeycombing with emphysema was also observed in 11 CPFE patients.ConclusionsTWCLs were only observed in the CPFE patients. They were classified as lesions with coexistent fibrosing interstitial pneumonia and emphysema, and should be considered an important pathological and radiological feature of CPFE.

The clinical course of chronic hypersensitivity pneumonitis (HP) with fibrosis is similar to that of idiopathic pulmonary fibrosis (IPF). Current research is expected to identify biomarkers effective in predicting the deterioration of lung function in a clinical setting. Our group analyzed the relationships between the following parameters in chronic bird-related HP: patient characteristics, serum markers, lung function, HRCT findings, BALF profiles, and the worsening of lung function. We also analyzed serum levels of CXCL9, CCL17, and Krebs von den Lungen 6 (KL-6) as serum markers. Patients showing declines in vital capacity (VC) of over 5% at 6 months after first admission were categorized as the “decline group”; the others were categorized as the “stable group.” The serum level of CCL17 and the percentage of BALF macrophages were significantly higher in the decline group compared to the stable group. Serum levels of CXCL9 and CCL17 were significant variables in a multivariate logistic regression analysis of factors associated with VC decline. Patients with a chemokine profile combining lower serum CXCL9 and higher serum CCL17 exhibited significantly larger VC decline in a cluster analysis. Higher serum CCL17 and lower serum CXCL9 were important predictors of worsening lung function in patients with chronic bird-related HP.

The Keap1-Nrf2 system plays a pivotal role in the oxidative stress response by inducing a number of cytoprotective genes. Under stress, damaged epithelial cells release cytokines that activate type 2 innate lymphoid cells (ILC2s), which mediate the allergic immune response. In this article, we investigated the role of the Keap1-Nrf2 pathway in ILC2 homeostasis and allergic inflammation using Nrf2 knockout mice. ILC2s from Nrf2-deficient mice showed a transient, upregulated IL-33 response and underwent hyperproliferation in response to a combined stimulation of IL-33 with IL-2, IL-7, or TSLP. This enhanced proliferation was correlated with an increased activation of downstream signals, including JAK1, Akt, and Erk1/2. In contrast, activating Nrf2 with a chemical inducer (CDDO-Im) decreased the viability of the wild-type but not of the Nrf2-deficient ILC2s. This effect on viability resembled that exerted by the corticosteroid dexamethasone; however, unlike the latter, the Nrf2-dependent cell death was mediated by neither caspase 3-dependent apoptosis nor necroptosis. Using a mouse intratracheal IL-33 administration allergy model, we found that the activation of Nrf2 by CDDO-Im in vivo decreased the number of pulmonary ILC2s and eosinophils. These findings indicated that Nrf2 is an important regulator of the allergic response by determining the survival and death of ILC2s, and these findings suggest that Nrf2 activation is a potential therapeutic strategy for steroid-resistant allergy alleviation.

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BACKGROUND The clinical course and prognosis of progressive fibrosing interstitial lung diseases (PF-ILDs) vary from individual to individual. Predictive serum biomarkers for the management of the disease are needed. Serum human epididymis protein 4 (HE4) has been reported to be elevated in patients with IPF, yet its clinical utility has not been elucidated. We evaluated whether serum HE4 could be a biomarker for patients with PF-ILD. METHODS Serum HE4 was measured in a retrospective study that consisted of 34 patients with PF-ILD and 40 healthy volunteers. The relationship between serum HE4 levels and clinical parameters or prognosis was investigated. To validate the significance of the results, a prospective observational study that consisted of 37 patients with PF-ILD and 40 control patients without PF-ILD was performed. RESULTS Serum HE4 was higher in patients with PF-ILD than in health volunteers (P < 0.01). A correlation of the serum HE4 levels with the extent of honeycombing on chest high-resolution computed tomography was identified (r = 0.41, P = 0.015). In multivariate analysis by the Cox proportional hazard model, higher HE4 levels (> 238 pmol/l) were associated with elevated mortality risk (HR 7.27, 95% CI 1.56-34.0, P = 0.01 in the derivation cohort; HR 44.3, 95% CI 4.19-468, P < 0.01 in validation cohort). CONCLUSIONS Serum HE4 levels may serve as a new diagnostic and prognostic biomarker for patients with PF-ILD.