Survival and free from AE in chronic bird-related HP patients divided into the higher-CCL17/CXCL9 group (CCL17/CXCL9 ≥ 24.8) and lower-CCL17/CXCL9 group (CCL17/CXCL9 < 24.8) were analyzed using Kaplan-Meier survival curves (S2 Fig). This evidence concerns the gene CXCL9 and hypersensitivity pneumonitis.