HMGB1 and pneumonia: S. pneumoniae being the most common etiology of CAP in all severity classes, they analyzed local (sputum) and systemic (plasma) HMGB1 concentrations and found that the levels were significantly higher in patients infected by S. pneumoniae compared to other etiologies, while no correlation was found between HMGB1 levels in plasma and sputum and between HMGB1 concentration and pneumonia severity [127].