Neutralizing the complement component C5a protects against lung injury and extrapulmonary organ injury in pneumococcal pneumonia induced sepsis

Rationale: Severe community acquired pneumonia (sCAP) and resultant sepsis cause high lethality despite adequate antibiotic treatment. S. pneumoniae is the most prevalent causative pathogen of sCAP. Uncontrolled inflammatory host responses likely contribute to unfavourable outcome by aggravating lung and extrapulmonary organ injury. The complement system is involved in the immune response against infection but also contributes to hyperinflammation and vascular barrier failure mainly mediated by the complement fragment C5a, an anaphylatoxin. We thus aimed to investigate the regulation of C5a in pneumonia and hypo…