Studies have shown that propionate mitigates pneumonia severity and lung tissue remodeling by reducing the infiltration of neutrophils, eosinophils, and lymphocytes, and by interfering with the release of chemokine C-X-C Motif Chemokine Ligand 1(CXCL1) and inflammatory factor TNF-α [82]. Here, XCL1 is linked to susceptibility to pneumonia measurement.