To our knowledge, this is the first report of PD-L1 expression by neutrophils during in vivo infection, although a recent report has shown that treatment of neutrophils with IFN-γ and GM-CSF upregulated PD-L1 [18] and an earlier report showed that LPS stimulation could upregulate PD-L1 on neutrophils [19]. Here, IFNG is linked to infection.