DARS2 and susceptibility to pneumonia measurement: The contributions here suggest that (i) DARS2 is a secreted, acetylated biomolecule with immunostimulatory properties found in the plasma of people with pneumonia, (ii) the cellular abundance of this enzyme is reduced, in part, by the SCFFBXO24 machinery, and (iii) an FBXO24 small molecule antagonist restores DARS2 levels and displays immunostimulatory activity.