Human epididymis protein 4 is a new biomarker to predict the prognosis of progressive fibrosing interstitial lung disease.

The clinical course and prognosis of progressive fibrosing interstitial lung diseases (PF-ILDs) vary between individuals. Notably, predictive serum biomarkers for disease management are needed. Serum human epididymis protein 4 (HE4) is reportedly elevated in patients with idiopathic pulmonary fibrosis (IPF); however, its clinical utility remains unknown. We evaluated the potential of serum HE4 as a biomarker for patients with PF-ILD. Serum HE4 was measured in a retrospective study consisting 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 results obtained, a prospective observational study was performed in 37 patients presenting PF-ILD and 40 control patients without PF-ILD. Serum HE4 levels were higher in patients with PF-ILD than in healthy volunteers (P < 0.01). Moreover, serum HE4 levels correlated with the extent of honeycombing on chest high-resolution computed tomography (r = 0.41, P = 0.015). In multivariate analysis using the Cox proportional hazard model, higher HE4 levels (>238 pmol/L) were associated with an elevated mortality risk; hazard ratio (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. Serum HE4 levels may serve as a new diagnostic and prognostic biomarker for patients with PF-ILD.

Nishiyama N ，Masuo M ，Nukui Y ，Tateishi T ，Kishino M ，Tateishi U ，Morota K ，Ohbo K ，Miyazaki Y ... -  《-》

Human epididymis protein 4 is associated with severity and poor prognosis of connective tissue disease-associated interstitial lung disease with usual interstitial pneumonia pattern.

Overexpression of human epididymis protein 4 (HE4) was previously described in idiopathic pulmonary fibrosis (IPF), but whether serum HE4 can be considered as a potential biomarker in connective tissue disease-associated interstitial lung disease (CTD-ILD) with usual interstitial pneumonia (UIP) pattern was still unknown. A total of 55 CTD-ILD patients with UIP pattern (UIP-CTD) and 52 healthy controls were enrolled in this study. The serum levels of HE4 and Krebs von den Lungen-6 (KL-6) were evaluated in both cohorts. In addition, immunohistochemistry analysis for HE4 was performed on the lung sections of 6 patients with rheumatoid arthritis-associated UIP (UIP-RA) and 6 patients with early-stage lung cancer as normal control. The levels of serum HE4 and KL-6 were higher in patients with UIP-CTD than in healthy controls (292.3 pmol/L versus 79.5 pmol/L for HE4, p < 0.001; 1091.0 IU/mL versus 171.5 IU/mL for KL-6, p < 0.001). Significant correlations between serum HE4 levels and percentpredicted forced vital capacity (FVC%) (r = -0.425, p = 0.004), percent predicted diffusing capacity of the lung for carbon monoxide (DLCO%) (r = -0.447, p = 0.003), and Gender-Age-Physiology (GAP) index (r = 0.494, p < 0.001) were observed in UIP-CTD patients. In immunohistochemistry analysis, elevated expression of HE4 in bronchiolar epithelium and mesenchyme was observed in patients with UIP-RA compared with controls. The serum levels of HE4 (≥277.5 pmol/L) and GAP index were related to an increased risk of mortality (HR = 3.884, p = 0.034; HR = 1.480, p = 0.028, respectively). The expression of HE4 in serum and lung specimens was significantly elevated in UIP-CTD patients. Moreover, serum HE4 may be utilized as a biomarker to evaluate the severity of disease and predict the prognosis of UIP-CTD patients.

Meng K ，Tian M ，Gui X ，Xie M ，Gao Y ，Shi S ，Zhao T ，Xiao Y ，Cai H ，Ding J ... -  《-》

Elevated serum human epididymis protein 4 is associated with disease severity and worse survival in idiopathic pulmonary fibrosis: a cohort study.

Elevated expression of human epididymis protein 4 (HE4) was previously described in connective tissue disease-associated interstitial lung diseases (CTD-ILDs) and cystic fibrosis (CF), but the clinical significance of HE4 has remained unknown in idiopathic pulmonary fibrosis (IPF), which is a progressive fibrosing ILD with a heterogeneous course that is in urgent need of reliable biomarkers in its clinical practice. A total of 27 IPF patients with acute exacerbation status (AE-IPF), 32 IPF patients with stable status (S-IPF), and 29 sex-age matched healthy controls were retrospectively included. The levels of serum HE4 and Krebs von den Lungen-6 (KL-6) of the 3 cohorts were measured. In addition, the pulmonary expression of HE4 was evaluated in lung transplant specimens of IPF using immunohistochemistry and Western blot, and noncancerous lung tissue resected from early-stage lung cancer patients as controls. The endpoint of follow-up was March 1st, 2022, and the Cox regression model was used to analyze the prognostic value of HE4. The levels of HE4 and KL-6 were obviously elevated in AE-IPF patients compared to S-IPF (296.4 vs. 178.1 pmol/L for HE4, P<0.001; 2,007.0 vs. 990.5 IU/mL for KL-6, P<0.001) or healthy controls (296.4 vs. 51.8 pmol/L for HE4, P<0.001; 2,007.0 vs. 181.0 IU/mL for KL-6, P<0.001). Significant correlations were observed between serum HE4 levels and percent predicted diffusing capacity of the lung for carbon monoxide (DLCO%) (r=-0.526, P<0.001), percent predicted forced vital capacity (FVC%) (r=-0.344, P=0.024), gender-age-physiology (GAP) index (r=0.535, P<0.001), and oxygenation index (r=-0.550, P<0.001) in IPF patients. In histological analysis, overexpression of HE4 in mucosal epithelium of dilated bronchi was observed in IPF patients compared with controls. Multivariate cox regression revealed that serum levels of HE4 [hazard ratio (HR) =1.004, P=0.042] and GAP index (HR =1.374, P=0.010) were associated with worse survival in IPF patients. The expression of serum HE4 was obviously elevated in IPF patients, especially in AE-IPF patients. In addition, serum HE4 could be utilized as a biomarker of disease severity and poor prognosis of IPF patients. These findings warrant further validation in larger, multi-center, and longitudinal cohorts.

Tian M ，Meng K ，Gao Y ，Zhang J ，Xie M ，Tian Y ，Liu X ，Ma M ，Cai Y ，Wu H ，Ding J ，Chen J ，Cai H ... -  《-》

Human epididymis protein 4 as a new diagnostic biomarker for rheumatoid arthritis-associated interstitial lung disease.

Lin T ，Xu S ，Wang Y ，Nian X ，Shan X ，Jiang T ，Qiu M ... -  《CLINICAL AND EXPERIMENTAL RHEUMATOLOGY》

Progressive fibrosing interstitial lung disease: prevalence and clinical outcome.

The progressive fibrosing (PF) phenotype of interstitial lung disease (ILD) is characterised by worsening respiratory symptoms, lung function, and extent of fibrosis on high-resolution computed tomography. We aimed to investigate the prevalence and clinical outcomes of PF-ILD in a real-world cohort and assess the prognostic significance of the PF-ILD diagnostic criteria. Clinical data of patients with fibrosing ILD other than idiopathic pulmonary fibrosis (IPF) consecutively diagnosed at a single centre were retrospectively reviewed. A PF phenotype was defined based on the criteria used in the INBUILD trial. The median follow-up duration was 62.7 months. Of the total of 396 patients, the mean age was 58.1 years, 39.9% were men, and rheumatoid arthritis-ILD was the most common (42.4%). A PF phenotype was identified in 135 patients (34.1%). The PF-ILD group showed lower forced vital capacity and total lung capacity (TLC) than the non-PF-ILD group. The PF-ILD group also showed poorer survival (median survival, 91.2 months vs. not reached; P < 0.001) than the non-PF-ILD group. In multivariable Cox analysis adjusted for age, DLCO, HRCT pattern, and specific diagnosis, PF phenotype was independent prognostic factor (hazard ratio, 3.053; P < 0.001) in patients with fibrosing ILD. Each criterion of PF-ILD showed similar survival outcomes. Our results showed that approximately 34% of patients with non-IPF fibrosing ILD showed a progressive phenotype and a poor outcome similar to that of IPF, regardless of the diagnostic criteria used.

Kwon BS ，Choe J ，Chae EJ ，Hwang HS ，Kim YG ，Song JW ... -  《RESPIRATORY RESEARCH》