C5a concentrations are elevated in human and murine pneumonia. (A) C5a was quantified in serum of patients with community-acquired pneumonia enrolled within 48 h of hospitalization (n = 395) and in healthy controls (ctrl, n = 24). Pneumonia patients had higher serum concentrations of C5a. (B and C) Mice were transnasally infected with Streptococcus pneumoniae (S. pn.; 5 × 106 colony-forming units/mouse) or sham-infected with phosphate-buffered saline, and 24 h or 48 h after infection C5a concentrations in plasma (B) and bronchoalveolar lavage fluid (BALF; C) were measured. In (B), n = 12 (sham, S. pneumoniae 24 h) or n = 11 (S. pneumoniae 48 h); in (C), n = 10 (sham) or n = 11 (S. pneumoniae). (A–C) Data are represented as box plots depicting median, quartiles, and ranges excluding outliers (open circles). (A) *P < 0.05 (Mann–Whitney U test). (B and C) **P < 0.01, ***P < 0.001 vs. sham-infected group (multiple Mann–Whitney U tests with Bonferroni correction for multiple comparisons).
