CXCL10 and pneumococcal pneumonia: Numerous experimental in vitro, in vivo, and clinical studies have reported several pro-inflammatory cytokines up-regulated during the early phase of pneumococcal pneumonia, including IL-6, G-CSF, TNF-α, IL-1β, IL-12, IFN-Υ, and IP-10 (Van Der Poll et al., 1997; Ethuin et al., 2004; Yamamoto et al., 2004; Palaniappan et al., 2006; Sun et al., 2007; Endeman et al., 2011; Yamada et al., 2011; Gomez et al., 2015; Skovbjerg et al., 2017; Loughran et al., 2018).