In accordance with these observations, we noted that a recruitment of lung CD4+ T lymphocytes (Figure 4 A), T regs (Figure 4 C) and Th17 cells (IL-17A, Figure 4 D), but not CD8+ T (Figure 4 B) or NK cells (not shown), was associated with lung fibrosis in WT animals after silica treatment. Here, IL17A is linked to pulmonary fibrosis.