Decreased interleukin-10 production by neonatal monocytes and T cells: Relationship to decreased production and expression of tumor necrosis factor- α and its receptors

The production of IL-10 by human neonatal blood mononuclear leukocytes (BML) stimulated with lipopolysaccharide (LPS), tumor necrosis factor-α (TNF-α), antibodies to CD3, or phorbol 12-myristate 13-acetate (PMA) was measured. The production of IL-10 by neonatal BML cultured with LPS or TNF- α was ~20 and ~15%, respectively, of adult BML. The combination of human recombinant TNF-α and LPS failed to augment IL-10 production in neonatal BML. The decreased production of IL-10 by neonatal leukocytes was not due to an autocrine feedback mechanism because only low concentrations of IL-10 were found in newborn sera. A connection with TNF-α could not be ruled out, because TNF-α production by LPS-stimulated newborn BML and the expression of TNF-α receptors on newborn monocytes were reduced. Mean ± SD of concentrations of IL-10 in supernatants from adult and neonatal BML after stimulation with antibodies to human CD3 for 48 or 72 h were 914 ± 386 and 178 ± 176 pg/mL, respectively (p < 0.0001). In experiments with enriched populations of neonatal T cells, the addition of PMA failed to augment IL-10 production. This suggested that newborn T cells may be in a different state of activation than adult T cells. Thus, IL-10 production in neonatal monocytes and T cells is reduced and this study suggests that the reduction may be secondary in part to regulatory processes involving TNF-α and its receptors.