Reduction in neutrophil cell surface expression of tumor necrosis factor receptors but not Fas after transmigration - Implications for the regulationof neutrophil apoptosis
Aje. Seely et al., Reduction in neutrophil cell surface expression of tumor necrosis factor receptors but not Fas after transmigration - Implications for the regulationof neutrophil apoptosis, ARCH SURG, 133(12), 1998, pp. 1305-1309
Objectives: To test the hypothesis that loss of polymorphonuclear neutrophi
l tumor necrosis factor alpha (TNF-alpha) receptors during transmigration r
enders the exudate neutrophil refractory to TNF-alpha-mediated stimulation
of apoptosis; and to investigate the surface expression of Fas on both circ
ulating and exudate neutrophils.
Design: A prospective cohort study.
Setting: Surgical laboratory of a tertiary care hospital.
Participants: Twenty-one healthy human volunteers.
Interventions: All subjects had circulating neutrophils and exudate neutrop
hils collected by venipuncture and skin window methods, respectively.
Main Outcome Measures: Circulating and exudate neutrophils were incubated i
n culture medium (1.0 x 10(6) neutrophils per milliliter) alone or with TNF
-alpha (100 ng/mL). Apoptosis was evaluated by flow cytometry (annexin V-fl
uorescein isothiocyanate and propidium iodide). Tumor necrosis factor alpha
-phycoerythrin and anti-human Fas-fluorescein isothiocyanate were used to e
valuate neutrophil TNF-alpha receptors and surface expression of Fas.
Results: Exudate neutrophils had a significant delay in apoptosis races whe
n compared with circulating neutrophils. The percentage of neutrophils expr
essing TNF-alpha receptors was significantly diminished after exudation (80
% +/- 15% vs 33% +/- 9%; P<.001), as was the median channel number of TNF-a
lpha phycoerythrin fluorescence (8.1 +/- 1.6 vs 5.2 +/- 0.5; P = .001). How
ever, the expression of Fas was unchanged after transmigration (percentage
positive for Fas: 98.7% +/- 0.7% vs 92.8% +/- 3.4%, P = .89; Fas antibody-f
luorescein isothiocyanate median channel fluorescence: 12.2 +/- 1.1 vs 13.1
+/- 1.2; P = .80). Exposure of exudate neutrophils to TNF-alpha failed to
increase their rate of apoptosis.
Conclusions: Exudate polymorphonuclear neutrophils are confirmed to have de
layed apoptosis. Loss of TNF-alpha receptors during transmigration is neces
sary for neutrophil survival in the extravascular inflammatory milieu.