Role of interleukin-8 in community-acquired pneumonia: relation to microbial load and pulmonary function.
In pneumonia local phagocyte activation is crucial for clearing of pathogenic microorganisms. In this context alveolar macrophage interleukin-8 secretion, phagocyte oxidative response and concentrations of lavage proteins were quantified, including interleukin-8, in 31 patients with pneumonia, 13 age matched patients with peripheral lung consolidation and six healthy volunteers; these findings were related to the impairment of gas exchange and the bacterial load in the alveolar space. Increased interleukin-8 levels were found in bronchoalveolar lavage fluid (BALF) and in alveolar macrophage supernatants from patients with pneumonia (214 ng/10(5) AM +/- 121 vs 71 ng/10(5) AM +/- 35 and 66 ng/10(5) AM +/- 30, p < 0.05). Interleukin-8 release from alveolar macrophages correlated with the upregulated spontaneous luminol enhanced oxidative response of pulmonary phagocytes but not with the neutrophil count in BALF. In pneumonia patients a significant difference was found between patients with 10(4) or more colony forming units (CFU)/ml BALF of one pathogen and patients with less CFU or nonspecific microbiological results (261 ng/10(5) AM +/- 89 vs 179 ng/10(5) AM +/- 81 and 7.5 ng/ml BALF +/- 17 vs 0.44 ng/ml BALF +/- 1, p < 0.05). Further, a negative correlation between interleukin-8 release of alveolar macrophages and the arterial pO2 at the time of BALF could be demonstrated (r = -0.47, p < 0.05). The results demonstrate local cellular activation in community-acquired pneumonia, which is related to the bacterial load in the alveolar space and to impairment of gas exchange. This is consistent with the hypothesis that pulmonary phagocytes play a central role in the pathogenesis of bacterial pneumonia, contributing not only to bacterial clearing but also to local tissue damage.
Bohnet
S
S
Medizinische Klinik II, Medizinische Universität zu Lübeck, Germany.
Kötschau
U
U
Braun
J
J
Dalhoff
K
K
D000328:Adult; D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology / Q000276:immunology; D002478:Cells, Cultured; D015169:Colony Count, Microbial; D017714:Community-Acquired Infections / Q000276:immunology*; D005260:Female; D006193:Haemophilus influenzae / Q000302:isolation & purification; D006801:Humans; D016209:Interleukin-8 / Q000032:analysis / Q000502:physiology*; D007958:Leukocyte Count; D008165:Luminol / Q000494:pharmacology; D008171:Lung Diseases / Q000276:immunology / Q000382:microbiology / Q000503:physiopathology; D016676:Macrophages, Alveolar / Q000378:metabolism / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009177:Mycoplasma pneumoniae / Q000302:isolation & purification; D011010:Pneumocystis / Q000302:isolation & purification; D018410:Pneumonia, Bacterial / Q000276:immunology*; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification; D016897:Respiratory Burst; D012129:Respiratory Function Tests
D016209:Interleukin-8; D008165:Luminol