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07:28
Isolation, Purification and Labeling of Mouse Bone Marrow Neutrophils for Functional Studies and Adoptive Transfer Experiments
Published on: July 10, 2013
C5a mediates peripheral blood neutrophil dysfunction in critically ill patients
Andrew Conway Morris1, Kallirroi Kefala, Thomas S Wilkinson
1Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh, Scotland, UK.
American Journal of Respiratory and Critical Care Medicine
|March 28, 2009
Summary
Critically ill patients exhibit impaired neutrophil function, primarily due to activated complement. The inflamed lung also contributes to neutrophil dysfunction, independent of complement.
Area of Science:
- Critical care medicine
- Immunology
- Infectious disease
Background:
- Critically ill patients are prone to hospital-acquired infections.
- Neutrophil function in critical illness is not well understood.
Purpose of the Study:
- To characterize peripheral blood neutrophil (PBN) dysfunction in critically ill patients.
- To investigate the role of the inflamed lung in neutrophil phagocytic impairment.
Main Methods:
- Prospective collection of blood and bronchoalveolar lavage fluid from patients and volunteers.
- Laboratory analysis of neutrophil functions, including phagocytosis, migration, and bacterial killing.
Main Results:
- PBN phagocytic capacity was 36% lower in critically ill patients compared to healthy volunteers.
- Activated complement, specifically C3a and C5a, was strongly associated with impaired PBN phagocytosis.
- C5a impaired PBN phagocytosis, migration, and bacterial killing, while down-regulating CD88 expression.
- Leukocytes from bronchoalveolar lavage fluid also showed impaired function, and lavage supernatant reduced phagocytosis in healthy neutrophils.
Conclusions:
- Critically ill patients have significant PBN dysfunction mediated primarily by activated complement.
- The inflamed lung contributes to complement-independent neutrophil dysfunction.
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