L-Selectin Is Down-regulated in Umbilical Cord Blood Granulocytes and Monocytes of Newborn Infants with Acute Bacterial Infection

Abstract

The leukocyte glycoprotein L-selectin mediates an early step in the recruitment of leukocytes to sites of inflammation. L-Selectin surface expression is rapidly down-regulated by inflammatory signals in vitro. In a prospective study, we found L-selectin expression on umbilical cord blood granulocytes and monocytes to be significantly decreased in newborn infants with acute bacterial infection compared with controls (p < 0.01). A significantly reduced L-selectin expression of both granulocytes and monocytes was also found to be associated with an increased neutrophil immature/total ratio (p < 0.01) but not with other laboratory markers of neonatal sepsis. There was no apparent impact of prematurity, low birth weight, gestational hypertension, or gestational diabetes on L-selectin expression. Although the mode of delivery did not affect granulocyte L-selectin expression, umbilical cord blood monocytes showed an increased L-selectin expression after emergency cesarean delivery compared with samples obtained after elective cesarean or vaginal delivery (p < 0.01). We conclude that acute systemic inflammation results in down-regulation of granulocyte and monocyte L-selectin expression in vivo similar to that observed in vitro.

Comparison of L-Selectin and CD11b on Neutrophils of Adults and Neonates during the First Month of Life

“…Our findings of lower L-selectin on unstimulated term neonatal neutrophils are similar to those of previous studies in cord blood (4,5,15,16) and in neonates up to 48 h of age (4). Koenig et al (21) have reported that lysates of PMN from term neonatal cord blood have lower total L-selectin than adults, corroborating a cellular deficiency in the neonate.…”

“…Other studies have shown no differences with mode of delivery, as well (5,16,19,29). However, Weinschenk et al (32) did find a positive correlation between CD11b expression and labor length.…”

“…have demonstrated decreased emigration of neutrophils into an inflammatory site that was L-selectin and CD18-dependent. Studies have shown that neonatal L-selectin expression is decreased after dexamethasone treatment (26) and in cord blood of neonates with acute bacterial infection (16).…”

“…Cord blood neutrophils express a decreased amount of Lselectin when compared with adult controls (4,5,15,16). Most studies have shown a diminished up-regulation of CD11b expression after stimulation of neonatal neutrophils (5,(17)(18)(19).…”

Λεκτίνη συνδεόμενη με τη μαννόζη (mannose-binding lectin, MBL) και περιγεννητικές λοιμώξεις

“…Οι ποιοτικές διαφορές τους, όπου φαίνεται να υστερούν συγκριτικά με τους ενήλικες, αφορούν στην αντίδρασή τους σε χημειοτακτικά ερεθίσματα, στην ικανότητα προσκόλλησης και κύλισης στο αγγειακό ενδοθήλιο, στην προβολή λαμινοποδίων αλλά και στους μηχανισμούς βακτηριακής λύσης [17,20]. Αξιοσημείωτο είναι το γεγονός, ότι η μειωμένη ή πολύ αυξημένη έκφραση μορίων προσκόλλησης στα ουδετερόφιλα, όπως LFA-1 στα πρόωρα και CR3 ή L -σελεκτίνης σε όλα τα νεογνά κατά τη διάρκεια σήψης, περιορίζει την κύλιση και την επακόλουθη διαπίδυσή τους [21,22]. Τέλος, διαπιστώθηκε πως οι ιδιότητες αποκοκκίωσης των νεογνικών ουδετερόφιλων δε διαφέρουν μεταξύ πρόωρων και τελειόμηνων νεογνών, ωστόσο το περιεχόμενό τους διαφέρει σημαντικά σε σχέση με τους ενήλικες.…”