Phagocytic ability of neutrophils and monocytes in neonates

Abstract

BackgroundInfections by a variety of pathogens are a significant cause of morbidity and mortality during perinatal period. The susceptibility of neonates to bacterial infections has been attributed to immaturity of innate immunity. It is considered that one of the impaired mechanisms is the phagocytic function of neutrophils and monocytes. The purpose of the present study was to investigate the phagocytic ability of neonates at birth.MethodsThe phagocytic ability of neutrophils and monocytes of 42 neonates was determined using the Phagotest flow cytometry method, that assesses the intake of E. Coli by phagocytes, in cord blood and in peripheral blood 3 days after birth. Fifteen healthy adults were included in the study as controls.ResultsThe phagocytic ability of neutrophils in the cord blood of neonates was significantly reduced compared to adults. The 3rd postnatal day the reduction of phagocytic ability of neutrophils was no longer significant compared to adults. The phagocytic ability of monocytes did not show any difference from that of adults either at birth or the 3rd postnatal day.ConclusionsOur findings indicate that the intake of E. Coli by phagocytes is impaired at birth in both preterm and full term neonates compared to adults. This defect is transient, with the phagocytic ability in neonates reaching that of the adults 3 days after birth.

Monocytes are essential for the neuroprotective effect of human cord blood cells following middle cerebral artery occlusion in rat

“…Adult monocytes can differentiate into macrophage and dendritic cells but they also scavenge toxins, produce cytokines, growth factors, reactive oxygen species, nitric oxide, prostaglandins, complement and proteolytic enzymes (see references (Auffray et al, 2009; Geissmann et al, 2008) for recent reviews) and can function as antigen presenting cells (Van Voorhis et al, 1983). In many respects, monocytes within HUCB are indistinguishable from adult monocytes (Filias et al, 2011; Gille et al, 2009), but they are not stimulated by hepatocyte growth factor (Jiang et al, 2001), produce fewer dendritic cells compared to adult monocytes (Liu et al, 2001) and also produce lower concentrations of pro- and anti-inflammatory cytokines (Brichard et al, 2001; Jiang et al, 2001; Le et al, 1997). A recent report in a model of diabetic retinopathy demonstrated that CD14+ HUCB cells became alternatively activated M2 macrophage that stimulated the resident myeloid cells to also become alternatively activated (Marchetti et al, 2011).…”

Phagocyte dysfunction in polymyalgia rheumatica and other age-related, chronic, inflammatory conditions

“…The pathologic substrate in PMR is synovitis characterized by vascular proliferation and infiltration of macrophages and lymphocytes [8]. However, the function of these infiltrating phagocytes remains 1 unclear. There is only one study in which neutrophil chemotaxis has been studied, in 8 patients with active PMR, and it was found to be normal [9].…”

“…Several factors contribute to the efficient function of the phagocytic system. These factors include the presence of an adequate number of monocytes and neutrophils in the peripheral blood, the ability to respond to signals from sites of inflammation, induction of migration to these sites, and the capacity to ingest and kill the invader microorganisms [1].…”

Morphological abnormalities of blood and bone marrow leukocytes and age-related changes in different leukocyte counts in the American mink (Neovison vison)

“…It is known that sapphire puppies are characterized by increased embryonal and early postnatal mortality as well as low weight at birth (2). In this connection it is important that the phagocytic ability of leukocytes in neonatal animals correlates with birth weight (19). Sapphire puppies in the first 10 days of life demonstrated retarded growth.…”