ABSTRACT
PURPOSE: Immature immunological defens mechanism in the neonate may contribute to the high susceptibility to overwhelming sepsis. S. aureus TSST-1 and E. coli LPS known as one of the important pathogens of septic shock or toxic shock induce massive release of various cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-1alpha (IL-1alpha) produced from peripheral blood mononuclear cells (PBMC). In contrast, limited information has been provided so far concerning the capacity of cytokine production from neonatal immune cells. METHODS: This study was conducted to compare the secretion of proinflammatory cytokines, such as IL-l and TNF-alpha from cord blood PBMC to those from adult blood PBMC stimulated by S. aureus TSST-1 and E. coli LPS. RESULTS: 1) IL 1-alpha was secreted in a time-dependent manner from cord & adult blood PBMC stimulated with several cytokine inducers, and LPS stimulated adult & cord blood PBMC secreted IL 1-alpha in a dose-dependent manner. 2) TNF-alpha secretion from cord blood PBMC stimulated with LPS and IFN- significantly decreased in a time dependent manner, but not from adult PBMC. And secretion of TNF- from cord blood PBMC reached the highest level 24 hours after stimulated with LPS or IFN-gamma. The secretion of TNF-alpha from adult blood PBMC showed similar pattern to those from cord blood PBMC, but higher than cord blood PBMC. 3) IL-1alpha & TNF-alpha secretion from cord & adult blood PBMC stimulated with TSST-1 had no significant difference except in TNF- secretion by TSST-1 at 96 hours. 4) The secretion of IL-1alpha from adult PBMC stimulated with LPS showed higher and longer than that from cord blood PBMC. 5) IL-1alpha & TNF-alpha secretion from cord & adult blood PBMC stimulated with IFN-gamma had no significant difference. CONCLUSIONS: In summary, proinflammatory cytokines such as IL-1alpha, TNF-alpha in cord blood PBMC were secreted in a time dependent manner, but the amounts of IL-1alpha and TNF-alpha secretion were lesser than those of adult blood PBMC, especially stimulated by LPS. These results suggest that increased susceptibility to infection in neonatal period may be partially from a functional immaturity of cord blood mononuclear cells.