Local and systemic cytokine profiles in nonsevere and severe community-acquired pneumonia

Local inflammatory responses in community-acquired pneumonia (CAP) remain insufficiently elucidated, especially in patients with nonsevere CAP. In this study we determined local and systemic cytokine responses in CAP patients and correlated these with disease severity and other clinical parameters. Levels of interleukin (IL)-6, IL-8, IL-10, IL-1β, tumour necrosis factor-a, interferon (IFN)-γ, IL-22, IL-17A and IL-4 were determined in bronchoalveolar lavage fluid and serum of 20 CAP patients upon admission and 10 healthy individuals. Systemic cytokine levels were also measured on days 7 and 30. In bronchoalveolar lavage fluid of CAP patients, levels of IL-6, IL-8 and IFN-γ were significantly increased compared with healthy individuals, but no correlations with disease severity were found. Systemic levels of IL-6, IL-10 and IFN-γ were significantly higher in severe CAP patients than in nonsevere CAP patients and healthy individuals. Moreover, these cytokines showed a significant correlation with the pneumonia severity index. In the total group of CAP patients, systemic IL-8 and IL-22 levels were also increased compared with healthy individuals. We therefore conclude that IL-6, IL-10 and IFN-γ are important cytokines in CAP, although differences in disease severity upon admission are only reflected by systemic levels of these cytokines. Copyrigh

T helper 17 cells are involved in the local and systemic inflammatory response in community-acquired pneumonia

Background Recent findings in mouse models suggest that T helper (Th)17 cells, characterised by production of interleukin (IL)-17A and IL-22, are involved in the immunopathogenesis of pneumonia. Objective In this study, we aimed to identify the involvement of Th17 cells in human community-acquired pneumonia (CAP). Design Within 24 h of admission, T cells from peripheral blood (n=39) and bronchoalveolar lavage (BAL, n=20) of CAP patients and of 10 healthy individuals were analysed by intracellular flow cytometry for the production of various cytokines, including IL-17A and IL-22. Peripheral blood T cells were also analysed 7 and 30 days after admission. Th17 cytokine profiles were correlated with pneumonia severity index and microbial aetiology. Results In the BAL of CAP patients, proportions of IL17A and IL-22 single positive, as well as IL-17A/IL-22 double positive CD4 T cells were significantly increased compared with healthy individuals. Significantl