The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
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Clinical Trial
Interleukin-17-producing T-helper cells and related cytokines in human airways exposed to endotoxin.
Previous studies on mouse models have indicated that interleukin (IL)-17 and IL-17-producing T-helper (Th) cells are important for pulmonary host defence against Gram-negative bacteria. Human correlates to these findings have not yet been demonstrated. The aim of the present study was to determine whether or not IL-17-producing Th cells are present and whether IL-17 and other Th17-associated cytokines are involved in the immunological response to endotoxin in human airways. ⋯ Th cells with the capacity to produce IL-17 were found among the bronchoalveolar lavage cells, and expression of IL-17 mRNA correlated with expression of the transcription factor, retinoic-acid-receptor-related orphan receptor C variant 2. Moreover, endotoxin increased the numbers of neutrophils, macrophages and IL-17-producing T-cells, as well as the concentration of the Th17-regulating cytokines, IL-21 and IL-23. In conclusion, IL-17-producing Th cells are present, and IL-17, as well as other Th17-associated cytokines, is involved in the immunological response to endotoxin in human airways.
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Anti-tumour necrosis factor (TNF) monoclonal antibodies or soluble TNF receptors have become an invaluable treatment against chronic inflammatory diseases, such as rheumatoid arthritis, inflammatory bowel disease and psoriasis. Individuals who are treated with TNF antagonists are at an increased risk of reactivating latent infections, especially tuberculosis (TB). Following TNF antagonist therapy, the relative risk for TB is increased up to 25 times, depending on the clinical setting and the TNF antagonist used. ⋯ Moreover, paediatric practice suggests concomitant use of both the tuberculin skin test and an interferon-γ release assay, as there are insufficient data in children to recommend one test over the other. Consequently, targeted preventive chemotherapy is highly recommended for all individuals with persistent M. tuberculosis-specific immune responses undergoing TNF antagonist therapy as it significantly reduces the risk of progression to TB. This TBNET consensus statement summarises current knowledge and expert opinions and provides evidence-based recommendations to reduce the TB risk among candidates for TNF antagonist therapy.
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Hypoxic pulmonary vasoconstriction (HPV) is an essential mechanism to optimise lung gas exchange. We aimed to decipher the proposed oxygen sensing mechanism of mitochondria in HPV. Cytochrome redox state was assessed by remission spectrophotometry in intact lungs and isolated pulmonary artery smooth muscle cells (PASMC). ⋯ Pharmacological inhibition of mitochondria revealed analogous kinetics of cytochrome redox state and strength of HPV. Our data suggest inhibition of complex IV as an essential step in mitochondrial oxygen sensing of HPV. Concomitantly, increased superoxide release from complex III and mitochondrial membrane hyperpolarisation may initiate the cytosolic calcium increase underlying HPV.