Serum interleukin-17 predicts severity and prognosis in patients with community acquired pneumonia: a prospective cohort study

Abstract

Background: Some studies previously demonstrated that interleukin-17 (IL-17) involves in pulmonary diseases progression. Nevertheless, the role of IL-17 in community-acquired pneumonia (CAP) remains unknown. This study aims to examine the correlations between serum IL-17 with the severity and prognosis in CAP patients through a prospective cohort study.

Methods: All 239 CAP patients were recruited. Serum IL-17 was detected by enzyme-linked immunosorbent assay (ELISA). The CAP severity was evaluated through CAP severity scores, including CURB-65, CRB-65, PSI, SMART-COP, CURXO and APACHE II.

Results: Serum IL-17 was gradually increased consistent with the severity of CAP. Correlative analysis suggested that serum IL-17 was associated with clinical physiologic indicators among CAP patients. Logistic regression indicated that serum IL-17 was positively related to CAP severity scores. Additionally, the prognostic outcomes were tracked among CAP patients. The levels of IL-17 on admission were significantly increased in CAP patients with ICU admission, mechanical ventilation, vasoactive agent, death and longer hospitalization days. Logistic regression analyses revealed serum higher IL-17 on admission elevated the risks of vasoactive agent usage and longer hospital stays in CAP patients. The cut-off concentrations of serum IL-17 for death, ICU admission, mechanical ventilation and ≥ 14 hospital stays were 86.80 ng/mL, 84.92 ng/mL, 84.92 ng/mL and 60.29 ng/mL respectively.

Conclusions: Serum IL-17 on admission is positively associated with the severity and poor prognosis among CAP patients, revealing that IL-17 may implicate in the pathological process of CAP. Therefore, serum IL-17 may become an effective biomarker for diagnosis, prognosis and therapy for CAP patients.

Keywords: Biomarker; CAP severity scores; Community-acquired pneumonia; Interleukin-17; Prognosis.

Fig. 1

The levels of serum IL-17 in CAP patients with different severity scores. A–F The levels of serum IL-17 in CAP patients with different severity scores. A CRB-65 score. B SMART-COP score. C APACHE II score. D CURB-65 score. E CURXO score. F PSI score. All data were expressed as mean ± SEM. *P < 0.05, **P < 0.01

Fig. 2

The levels of serum IL-17 in CAP patients with different prognostic outcomes. A–E The levels of serum IL-17 in CAP patients with different prognostic outcomes during hospitalizations. A Mechanical ventilation. B Vasoactive agent. C ICU admission. D Lengths of hospital stay. E Death. All data were expressed as mean ± SEM. *P < 0.05, **P < 0.01

Fig. 3

Receiver operating characteristic curves for prognosis in CAP patients. A ROC curve was used to evaluate the predictive values for death of different biomarkers among CAP patients. B ROC curve was used to evaluate the predictive values for ICU admission of different biomarkers among CAP patients. C ROC curve was used to evaluate the predictive values for mechanical ventilation of different biomarkers among CAP patients. D ROC curve was used to evaluate the predictive values for hospital stays of different biomarkers among CAP patients