HMGB1 and susceptibility to pneumonia measurement: HMGB1 is a highly conserved non-histone chromosome binding protein, which is closely related to a variety of lung diseases, including pneumonia (Tseng et al., 2014), tuberculosis (Zeng et al., 2015), chronic obstructive pulmonary disease (Sukkar et al., 2012), pulmonary fibrosis (Smit et al., 2014), and lung transplantation (Weber et al., 2014).