Interleukin-17A is involved in bacteria-related acute pleural inflammation.

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.

Epidemiological characteristics and outcomes from 187 patients with COVID-19 admitted to 6 reference centers in Greece: an observational study during the first wave of the COVID-19 pandemic.

INTRODUCTION: Epidemiological data from patients with COVID-19 has been recently published in several countries. Nationwide data of hospitalized patients with COVID-19 in Greece remain scarce. MATERIAL AND METHODS: This was an observational, retrospective study from 6 reference centers between February 26 and May 15, 2020. RESULTS: The patients were mostly males (65.7%) and never smokers (57.2%) of median age 60 (95% CI: 57.6-64) years. The majority of the subjects (98%) were treated with the standard-of-care therapeutic regimen at that time, including hydroxychlo-roquine and azithromycin. Median time of hospitalization was 10 days (95% CI: 10-12). Twenty-five (13.3%) individuals were intubated and 8 died (4.2%). The patients with high neutrophil-to-lymphocyte ratio (NLR) ( > 3.58) exhibited more severe disease as indicated by significantly increased World Health Organization (WHO) R&D ordinal scale (4; 95% CI: 4-4 vs 3; 95% CI: 3-4, p = 0.0001) and MaxFiO2% (50; 95% CI: 38.2-50 vs 29.5; 95% CI: 21-31, p < 0.0001). The patients with increased lactate dehydrogenase (LDH) levels ( > 270 IU/ml) also exhibited more advanced disease compared to the low LDH group ( < 270 IU/ml) as indicated by both WHO R&D ordinal scale (4; 95% CI: 4-4 vs 4; 95% CI: 3-4, p = 0.0001) and MaxFiO2% (50; 95% CI: 35-60 vs 28; 95% CI: 21-31, p < 0.0001). CONCLUSION: We present the first epidemiological report from a low-incidence and mortality COVID-19 country. NLR and LDH may represent reliable disease prognosticators leading to timely treatment decisions.