SLPI and interstitial lung disease: The levels of IL-17 in BAL were increased in F-ILD when compared to NF-ILD patients (8.93 ± 0.39 vs. 6.18 ± 0.43 pg/mL, p < 0.001, respectively) (Figure 3G) and were negatively correlated with SLPI (r = −0.49, p < 0.001) and lysozyme (r = −0.43, p < 0.001) levels in the BAL of ILD patients (Figure 3H,I).