In our study, eight cytokines (CCL21, a T-cell chemoattractant, IL-9, IL-17F, IL-21, IL-28A, I-309, MIP-1β, and TARC) significantly correlated with BDG exposure in those without fibrosis, while only two cytokines (eotaxin-3 and M-CSF) were correlated in those with fibrosis (Table 4). This evidence concerns the gene IL9 and fibrosis.