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Updated: May 16, 2026

Characterization of Immune Cells and Proinflammatory Mediators in the Pulmonary Environment
Published on: June 24, 2020
Interleukin-17A is involved in bacteria-related acute pleural inflammation
Androniki Kollintza1, Sofia Magkouta, Ioannis Psallidas
1Applied Biomedical Research and Training Center Marianthi Simou, Department of Critical Care and Pulmonary Services, General Hospital Evangelismos, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.
Background And Objective:
The role of pro-inflammatory interleukin-17A (IL-17A), in pleural diseases is unknown. We sought to investigate IL-17A expression and its clinical implications in patients with pleural effusion (PE) and IL-17A involvement in the pathobiology of pleural inflammation elicited by bacterial products.
Methods:
Pleural and blood IL-17A content was examined in 84 patients with PE of different aetiologies, and the diagnostic value of pleural IL-17A was explored in 92 patients with neutrophil-predominant PE. IL-17A contribution in pleural inflammation was evaluated in mice injected intrapleurally with either IL-17A or bacterial products with or without IL-17A-neutralizing antibodies.
Results:
IL-17A was upregulated in the pleural space of patients with parapneumonic PE. It was detected in a minority of patients with tuberculous PE and very uncommonly in patients with malignant or other pleural exudates. Pleural fluid (PF) IL-17A levels were correlated with markers of acute pleural inflammation, as well as vascular endothelial growth factor and IL-8 levels. Among patients with neutrophil-predominant PE, PF IL-17A was detected only in those with parapneumonic PE, although the sensitivity of the test was low (<50%). Intrapleural injection of IL-17A elicited a neutrophil-predominant inflammatory response in mice, and IL-17A neutralization partially blocked pleural neutrophilia induced by intrapleural administration of bacterial products.
Conclusions:
IL-17A is involved in pleural inflammation related to bacterial infection. Moreover, pleural IL-17A levels may be helpful in uncovering an infectious aetiology among patients with neutrophil-predominant PE.
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