Impaired Innate Immunity in the Newborn: Newborn Neutrophils Are Deficient in Bactericidal/Permeability-Increasing Protein

Abstract

These data suggest that the neutrophils of newborns are selectively deficient in BPI, a central effector of antibacterial activity against gram-negative bacteria. BPI deficiency correlates with decreased antibacterial activity of newborn neutrophil extracts against serum-resistant E coli and could contribute to the increased incidence of gram-negative sepsis among newborns relative to healthy adults.neonatal sepsis, gram-negative bacteria, endotoxin, neutrophil, polymorphonuclear leukocyte, innate immunity, bactericidal/permeability-increasing protein, defensin, myeloperoxidase.

Human β-defensin 2 expression in ELBW infants with severe necrotizing enterocolitis

“…Taken together, these data suggest that an impaired induction of hBD2 as part of an immature intestinal innate immune defense may play an important role particularly in NEC as ELBW infants with an increase in fecal hBD2 concentrations showed a much more moderate course of the disease. This hypothesis is in line with several reports demonstrating an impaired innate and adaptive immune response in ELBW infants (1,2,20). As hBD2 has been shown to be at least partly regulated by TLR4 and MD2 signaling (10,21), we investigated expression levels of these receptor molecules during and 14 wk after NEC in the two surviving patients.…”

“…t he innate and adaptive immune systems of extremely-lowbirth-weight (ELBW) infants are known to be immature, including deficiencies in neutrophil maturation and migration (1), deficient immunoglobulin production, and complement synthesis (2). Therefore, ELBW infants are generally highly susceptible to systemic infections and necrotizing enterocolitis (NEC), a potentially lethal condition with an overall mortality of 22-62% in this age group (3,4).…”

Invasive fungal infections in the pediatric population

“…For example, compared with older children and adults, neutrophils in the neonatal period have impaired chemotaxis and bactericidal activity [4,5], and T-cell regeneration following intensive chemotherapy, both in number and T-cell repertoire, critically depends on the age of the patient [6]. It is therefore not surprising that the epidemiology of IFI differs between children and adults.…”

The bactericidal/permeability-increasing protein (BPI) in infection and inflammatory disease

“…These findings suggest a possible explanation for how the pattern of expression of BPI can be different from that of many other azurophilic granule proteins. Of note, neutrophils in human newborn blood display an apparently selective deficiency of BPI compared to other granule proteins [37] that appears to account for the reduced antibacterial activity of extracts of these cells toward BPI-sensitive GNB.…”