Fig. 1
HE4 expression was up-regulated in the lung tissue and peripheral blood plasma of COPD patients. A–C Representative immunohistochemical images of human lung tissues against HE4 are shown. The tan staining was mainly presented in the bronchial epithelium. Compared with non-smokers and smokers, the degree and extent of tan staining was more pronounced and extensive in the bronchial epithelium of COPD patients. The staining alteration can be clearly observed by the arrowheads. Magnification = × 100. The red-boxed area indicates an area of higher magnification. D HE4 mRNA expression was increased in COPD patients. E, F Representative HE4 expression in the lung tissue homogenates was detected by Western blot and quantified using ImageJ. Each lane represents a different lung tissue subject. G Increased secretory HE4 was determined in the peripheral blood plasma of COPD patients relative to non-smokers and smokers. H Elevated sHE4 expression in plasma of COPD patients was negatively related with lung function. Data are expressed as mean ± SEM. For detection for lung tissues, n = 10 for non-smokers, n = 11 for smokers, and n = 11 for COPD. For detection for peripheral blood plasma, n = 12 for non-smokers, n = 15 for smokers, and n = 51 for COPD. P-values were calculated using one-way ANOVA followed by Newman–Keuls test. *P < 0.05, **P < 0.01, and ***P < 0.001 represent significant differences. HE4, human epididymis protein 4; COPD, chronic obstructive pulmonary disease; sHE4, secretory human epididymis protein 4; FEV1%pred, forced expiratory volume in 1 s (FEV1) % predicted