In Escherichia coli (E. coli)-induced pneumonia rodent models, MSCs improved bacterial clearance by secreting antimicrobial peptide LL-37, antibacterial protein lipocalin 2 (LCN-2) and keratinocyte growth factor (KGF) directly against bacteria or by enhancing macrophage phagocytosis [138–140]. Here, LCN2 is linked to susceptibility to pneumonia measurement.