Abstract

OBJECTIVES: The aim of the study was to evaluate the levels of interleukin (IL)-4, IL-10, transforming growth factor-beta (TGF-β), IL-17, and IL-23 cytokines, which reflect different T lymphocyte responses, in bronchoalveolar lavage (BAL) samples of tuberculin skin test (TST)-positive children.

MATERIAL AND METHODS: Twelve children with TST positivity, who underwent flexible videobronchoscopy (FB) to evaluate airway involvement and to obtain BAL to improve diagnostic yield, and 11 control children with negative TST, who underwent FB for other reasons, were enrolled in this case-control study. BAL samples were obtained from all children during the FB procedure. Levels of IL-4, interferon gamma (IFN-γ), IL-10, TGF-β, IL-17, and IL-23 were measured by the ELISA method.

RESULTS: Mean age of the children enrolled in the TST-positive and -negative groups were 8.6 (4.3) vs. 6.8 (4.5), respectively (p=0.35). There was a trend of higher TGF-β levels in TST-positive children compared with TST-negative children [557.9 (515.3) vs. 386.3 (208.1), respectively, p=0.07]. Mean levels of IL-23 were 39.2 (29.5) in TST-positive children vs. 46.2 (72.3) in TST-negative children (p=0.49). IFN-γ, IL-4, IL-10, and IL-17 levels were not significantly different among the groups (p>0.05 for all).

CONCLUSION: Results of this study suggest that TGF-β in BAL fluid of children with TST positivity tends to be higher than that in TST-negative children, which indicates an increased activity of regulatory T lymphocytes that may decrease the Th1 immune response. TGF-β might be studied in future research for its potential as a diagnostic modality and immunomodulatory treatment target.