Neutrophil activation in preterm infants who have respiratory distress syndrome.
OBJECTIVE
To study neutrophil activation in circulation as a sign of systemic inflammation in preterm infants with respiratory distress syndrome.


METHODS
The study comprised very low birth weight preterm infants who had respiratory distress syndrome and required intubation and mechanical ventilation (n = 51), 1-day-old preterm infants who had no need for mechanical ventilation (n = 12), term infants (n = 47), and adult volunteers (n = 25). Neutrophil surface expression of CD11b was quantified with flow cytometry.


RESULTS
In preterm infants with respiratory distress syndrome, neutrophil CD11b expression during the first day of life was higher than in cord blood (mean: 165 relative fluorescence units [RFU] [standard deviation [SD]: 53], n = 29 vs 83 RFU [SD: 21], n = 11; 95% confidence interval [CI] for difference: 59-106) or in preterm infants without mechanical ventilation (106 RFU [SD: 33], n = 12; 95% CI for difference: 17-90). CD11b expression decreased by age of 10 days. CD11b expression was lower in preterm cord than in term cord blood (95% CI for difference: 5-53). However, in preterm infants with respiratory distress syndrome aged 2 to 5 days, it was higher than in term infants of that age.


CONCLUSIONS
The observations demonstrate an early transient postnatal neutrophil activation indicative of systemic inflammation that may contribute to the tissue injury in preterm infants with respiratory distress syndrome.
Nupponen
Irmeli
I
Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland. irmeli.nupponen@kolumbus.fi
Pesonen
Eero
E
Andersson
Sture
S
Mäkelä
Aila
A
Turunen
Riikka
R
Kautiainen
Hannu
H
Repo
Heikki
H
D000367:Age Factors; D002657:Child Development / Q000502:physiology; D003131:Combined Modality Therapy; D005312:Fetal Blood / Q000737:chemistry / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000276:immunology; D019102:Infant, Very Low Birth Weight / Q000276:immunology; D007249:Inflammation / Q000276:immunology; D016177:Macrophage-1 Antigen / Q000097:blood; D018375:Neutrophil Activation / Q000276:immunology*; D011663:Pulmonary Surfactants / Q000627:therapeutic use; D012121:Respiration, Artificial; D012127:Respiratory Distress Syndrome, Newborn / Q000276:immunology* / Q000628:therapy
D016177:Macrophage-1 Antigen; D011663:Pulmonary Surfactants