ELEVATED INTERLEUKIN-1 EXPRESSION IN HUMAN NEONATAL NEUTROPHILS

Newborn infants have an increased morbidity and mortality from infection caused in part by diminished polymorphonuclear leukocyte (PMN) function and impaired recruitment of PMN to sites of inflammation. Recent studies in our laboratory and others have demonstrated the in vitro expression of several cytokines, including IL-1-beta, in adult human peripheral blood PMN. Because newborn infants have an impaired inflammatory response, we sought to compare the synthetic capability and regulation of cytokine expression in neonatal and adult PMN. In our present studies, we found that tumor necrosis factor-alpha and lipopolysaccharide could induce IL-1-beta expression in both neonatal and adult PMN and that neonatal PMN produced significantly more IL-1-beta when compared with adult PMN. The PMN chemotactic peptide fMet-Leu-Phe did not induce IL-1-beta expression in either adult or neonatal PMN. Elevated cytokine expression by neonatal PMN may play an important role in the regulation of the immune and inflammatory systems at sites of injury and infection in neonates.