BPI and influenza: In 2018, Dunning and colleagues (15) using a custom microarray on samples collected within approximately four days of symptom onset in 31 mechanically ventilated UK adults hospitalized for severe influenza with and without bacterial coinfection, reported increased expression of seven of these same neutrophil degranulation genes (RETN, TCN1, OLFM4, LCN2, BPI, MMP8, and LTF).