Abstract:

Objective

This study aimed to analyze the serum levels of cysteine-rich 61 （CCN1），eosinophil cationic protein （ECP），and glutathione peroxidase （GSH-Px） in patients with acute exacerbation of chronic obstructive pulmonary disease （AECOPD），exploring their correlation with pulmonary and immune function，as well as their potential diagnostic value in AECOPD.

Methods

A retrospective analysis was conducted on 55 AECOPD patients admitted to the Second Affiliated Hospital of Soochow University from January 2019 to June 2024 （observation group）.Forty-three stable COPD patients during the same period were selected as the control group.Serum CCN1，ECP，and GSH-Px levels were measured using enzyme-linked immunosorbent assay （ELISA）.Pulmonary function was assessed by measuring the percentage of predicted forced expiratory volume in one second （FEV₁%pred），FEV₁/forced vital capacity （FEV₁/FVC） ratio，and the percentage of predicted maximal mid-expiratory flow （MMEF%pred）.Immune function was evaluated by assessing CD4^＋and CD8^＋T-cell counts，as well as immunoglobulin A （IgA） and immunoglobulin M （IgM）levels.Pearson correlation analysis was used to evaluate the relationship between serum CCN1，ECP，and GSHPx levels and pulmonary and immune function.The diagnostic value of these biomarkers for AECOPD was assessed using receiver operating characteristic （ROC） curve analysis.

Results

The observation group had higher CCN1 （173.15±35.63 ng/ml） and ECP （30.16±4.25 ng/ml） levels compared to the control group（CCN1： 153.27±27.86 ng/ml； ECP： 19.23±2.84 ng/ml， P＜0.05），while GSH-Px levels （29.14±3.16）U/L were significantly lower than in the control group （46.36±3.77 U/L， P＜0.05）.Pulmonary function parameters in the observation group，including FEV₁%pred （58.43±5.13%），FEV₁/FVC （58.28±7.35%），and MMEF%pred （26.27±5.13%），were significantly lower than those in the control group （FEV₁%pred：74.18±10.04%；FEV₁/FVC： 67.41±7.90%； MMEF%pred： 40.07±5.79%， P ＜0.05）.Additionally，CD4^＋T-cell levels（29.93±3.12%） in the observation group were lower than in the control group （38.24±2.76%， P＜0.05），whereas CD8^＋T-cell levels （35.16±4.07%），IgA （264.72±17.49 mg/dl），and IgM （126.94±14.37 mg/dl）were higher than those in the control group （CD8^＋： 27.29±2.25%； IgA： 195.83±15.21 mg/dl； IgM： 95.57±10.94 mg/dl， P＜0.05）.Pearson correlation analysis revealed that serum CCN1 and ECP levels were negatively correlated with FEV₁%pred，FEV₁/FVC，and MMEF%pred （r＜0， P＜0.05） but positively correlated with CD8^＋，IgA，and IgM （r＞0，P＜0.05）.Conversely，GSH-Px levels were positively correlated with FEV₁%pred，FEV₁/FVC，and MMEF%pred （r＞0，P＜0.05） and negatively correlated with CD8＋，IgA，and IgM （r＜0，P＜0.05）.ROC analysis demonstrated that combined detection of serum CCN1，ECP，and GSH-Px achieved the highest diagnostic efficacy for AECOPD，with an area under the curve （AUC） of 0.973 （95%CI： 0.944-0.999），a sensitivity of 97.1%，a specificity of 97.8%，and a Youden index of 0.949.

Conclusion

Changes in serum CCN1，ECP，and GSH-Px levels in AECOPD patients are closely related to pulmonary and immune function，highlighting their diagnostic value as biomarkers for AECOPD.These findings support their potential application as predictive and monitoring tools in clinical practice.

Key words: Chronic obstructive pulmonary disease，acute exacerbation, Eosinophil cationic protein, Glutathione peroxidase, Pulmonary function, Immune function