Contrasting inflammatory responses in severe and non-severe community-acquired pneumonia

Inflammation. 2014 Aug;37(4):1158-66. doi: 10.1007/s10753-014-9840-2.


The objective of this study was to compare systemic and local cytokine profiles and neutrophil responses in patients with severe versus non-severe community-acquired pneumonia (CAP). Hospitalized patients with CAP were grouped according to the pneumonia severity index (PSI), as non-severe (PSI < 91 points) or severe (PSI ≥ 91 points). Blood and sputum samples were collected upon admission. Compared to non-severe CAP patients, the severe CAP group showed higher plasma levels of pro- and anti-inflammatory cytokines but in contrast, lower sputum concentrations of pro-inflammatory cytokines. Blood neutrophil functional responses were elevated in CAP patients compared to healthy controls. However, neutrophils from severe CAP patients showed reduced respiratory burst activity compared to the non-severe group. Results indicate that patients with severe CAP fail to mount a robust local pro-inflammatory response but exhibit instead a more substantial systemic inflammatory response, suggesting that a key driver of CAP severity may be the ability of the patient to generate an optimal local inflammatory response.

Publication types

  • Comparative Study
  • Observational Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Community-Acquired Infections / blood
  • Community-Acquired Infections / diagnosis*
  • Cytokines / metabolism
  • Female
  • Hospitalization
  • Humans
  • Inflammation / blood
  • Inflammation / diagnosis*
  • Male
  • Middle Aged
  • Neutrophils / metabolism
  • Patient Admission
  • Pneumonia / blood
  • Pneumonia / diagnosis*
  • Prospective Studies
  • Severity of Illness Index
  • Sputum / metabolism


  • Cytokines