Levels of HMGB1 in lower respiratory secretions have been correlated to disease severity in chronic obstructive pulmonary disease (COPD)13, asthma14, cystic fibrosis15, and acute lung injury in Legionella pneumophila pneumonia16, as well as to low oxygenation index in patients with pneumonia caused by Pneumocystis jirovecii17. This evidence concerns the gene HMGB1 and susceptibility to pneumonia measurement.