Abstract
Local inflammatory responses in community-acquired pneumonia (CAP) remain insufficiently elucidated, especially in patients with non-severe 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 (TNF)α, interferon (IFN)γ, IL-22, IL-17A and IL-4 were determined in bronchoalveolar lavage (BAL) 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 BAL fluid of CAP patients, levels of IL-6, IL-8, and IFNγ were significantly increased compared with healthy individuals, but no correlations with disease severity were found. Systemic levels of IL-6, IL-10 and IFNγ were significantly higher in severe CAP patients than in non-severe CAP patients and healthy individuals. Moreover, these cytokines showed a significant correlation with the pneumonia severity index (PSI). 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 IFNγ are important cytokines in CAP, although differences in disease severity upon admission are only reflected by systemic levels of these cytokines.
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