The systemic inflammatory response syndrome induces functional changes and relative hyporesponsiveness in neutrophils.
OBJECTIVE
To study the effects of systemic inflammatory response syndrome (SIRS) on polymorhonuclear neutrophil (PMN) function and phenotype by comparing neutrophils from critically ill patients with SIRS against those from healthy blood donors.


METHODS
Intensive care unit patients (n = 110) who met at least one SIRS criterion were recruited to the study. One hundred healthy blood donors were recruited as normal controls.


RESULTS
Polymorphonuclear cells from critically ill patients with SIRS were more resistant to activation than PMNs from healthy donors, but when stimulated had an exaggerated microbicidal response. Buffer-treated PMNs from patients with SIRS had significantly higher CD43 surface expression that may inhibit heterotypic cellular contact or ligand stimulation of membrane receptors, had significantly lower expression of IgG receptor CD16, demonstrated resistance to shedding of L-selectin when primed by platelet-activating factor which could be pro-inflammatory, and had reduced respiratory burst when primed by platelet-activating factor than activated by formyl-Met-Leu-Phe.


CONCLUSIONS
The phenotypic and functional changes observed in neutrophils in the critically ill indicate that they require a higher level of stimulus to become activated. This may represent an auto-protective mechanism where the neutrophils in the already inflamed host may, by this mechanism, avoid excessive inflammation reducing the risk of further host cell injury and death.
Fung
Yoke Lin
YL
Australian Red Cross Blood Service, PO Box 10325, Brisbane, QLD 4000, Australia. lfung@arcbs.redcross.org.au
Fraser
John F
JF
Wood
Peter
P
Minchinton
Robyn M
RM
Silliman
Christopher C
CC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000378:metabolism; D006801:Humans; D007362:Intensive Care Units; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism*; D016897:Respiratory Burst; D013481:Superoxides / Q000378:metabolism; D018746:Systemic Inflammatory Response Syndrome / Q000097:blood*; D055815:Young Adult
D015703:Antigens, CD; D013481:Superoxides