The association between the Th-17 immune response and pulmonary complications in a trauma ICU population

• Th-17 cytokine levels were significantly elevated in the BALF and blood of trauma patients.
• Th-17 cytokine levels did not differ between ARDS and non-ARDS patients.
• IL-6 cytokine levels in blood and BALF correlated with ARDS.

BackgroundThe overall immunopathology of the T-helper cell (Th)-17 immune response has been implicated in various inflammatory diseases including pulmonary inflammation; however its potential role in acute respiratory distress syndrome (ARDS) is not defined. This study aimed to evaluate the Th-17 response in bronchoalveolar lavage fluid (BALF) and blood and from trauma patients with pulmonary complications.MethodsA total of 21 severely injured intensive care unit (ICU) subjects, who were mechanically ventilated and undergoing bronchoscopy, were enrolled. BALF and blood were collected and analyzed for Th-1 (interferon [IFN]γ), Th-2 (interleukin [IL]-4, -10), Th-17 (IL-17A, -17F, -22, 23) and pro-inflammatory (IL-1β, IL-6, tumor necrosis factor [TNF]α) cytokine levels.ResultsSignificant levels of the Th-17 cytokines IL-17A, -17F and -21 and IL-6 (which can be classified as a Th-17 cytokine) were observed in the BALF of all subjects. There were no significant differences in Th-17 cytokines between those subjects with ARDS and those without, with the exception of plasma and BALF IL-6, which was markedly greater in ARDS subjects, as compared with controls and non-ARDS subjects.ConclusionsTrauma patients with pulmonary complications exhibited a significant Th-17 response in the lung and blood, suggesting that this pro-inflammatory milieu may be a contributing factor to such complications.