Abstract
Introduction: Previously vitro studies demonstrated that transcription factors STAT6 and PU.1 are required to induce IL-9 secretion by Th9 cells. The importance of STAT6 and PU.1 in human acute allergic asthma (AA) has not yet been well studied.
The aim: Evaluate p-STAT6 and PU.1 expression in peripheral blood Th9 cells during allergen-induced late phase airway inflammation in AA patients.
Material and Methods: 14 patients with intermittent/mild persistent AA and 11 healthy subjects (HS) were examined. Peripheral blood was collected 24 h before (baseline) and 24 h after bronchial allergen challenge. Th9 cells were defined by flow cytometry as CD4+IL-9+IFNγ-TGFβ1-IL-4-IL17-. p-STAT6 and PU.1 expression was obtained as mean fluorescence intensity (MFI) in Th9 cells. Serum IL-9 estimated by ELISA.
Results: There was no significant difference on p-STAT6 and PU.1 expression at baseline in AA and HS. P-STAT6 significantly increased in AA group 24 h after bronchial allergen challenge comparing with baseline: 81.8, range 67.2-90.5 MFI vs. 29.4, range 21.1-37.1 MFI; p=0.0001, accordingly. Same tendency was observed for PU.1 (99.5, range 68.9-112.8 MFI vs. 61.2, range 49.9-71.2 MFI; p=0.002, accordingly). After bronchial allergen challenge increased serum IL-9 level correlated with increased Th9 cells count (r=0.74, p=0.003) as well as with MFI of PU.1 (r=0.65, p=0.013) and STAT6 (r=0.56, p=0.041) in AA. In HS neither transcription factors nor IL-9 and Th9 cell count has changed after bronchial allergen challenge.
Conclusion: p-STAT6 and PU.1 are required for IL-9 production by Th9 cells in allergen-induced late phase airway inflammation in asthma patients.
- © 2014 ERS