L-SELECTIN IS DOWN-REGULATED IN UMBILICAL-CORD BLOOD GRANULOCYTES ANDMONOCYTES OF NEWBORN-INFANTS WITH ACUTE BACTERIAL-INFECTION

The leukocyte glycoprotein L-selectin mediates an early step in the re cruitment of leukocytes to sites of inflammation. L-Selectin surface e xpression is rapidly downregulated by inflammatory signals in vitro. I n a prospective study, we found L-selectin expression on umbilical cor d blood granulocytes and monocytes to be significantly decreased in ne wborn infants with acute bacterial infection compared with controls (p < 0.01). A significantly reduced L-selectin expression of both granul ocytes and monocytes was also found to be associated with an increased neutrophil immature/total ratio (p < 0.01) but not with other laborat ory markers of neonatal sepsis. There was no apparent impact of premat urity, low birth weight, gestational hypertension, or gestational diab etes on L-selectin expression. Although the mode of delivery did not a ffect granulocyte L-selectin expression, umbilical cord blood monocyte s showed an increased L-selectin expression after emergency cesarean d elivery compared with samples obtained after elective cesarean or vagi nal delivery (p < 0.01). We conclude that acute systemic inflammation results in down-regulation of granulocyte and monocyte L-selectin expr ession in vivo similar to that observed in vitro.