IFN-γ may play an important role in this neutrophil proliferation, as several studies showed its increased production from activated neutrophils during bacterial infection [77–79]Interestingly, IFN-γ, but not IFN-α or IFN-β stimulated neutrophils to acquire the ability to inhibit lymphocyte proliferation through the expression of programmed death ligand 1 (PD-L1) [80], which may explain the high count of neutrophils associated with overproduction of IFN-γ and lymphopenia [81–83]. Here, IFNG is linked to lymphopenia.