DIMINISHED TRANSCRIPTION OF INTERLEUKIN-8 BY MONOCYTES FROM PRETERM NEONATES

Developmental delays, which impair antibacterial host defense, are pre sent in the neutrophil system of human preterm neonates. We hypothesiz ed that diminished production of interleukin-8 (IL-8), a neutrophil ch emotactic peptide, might in part be responsible for these defects. To test this, monocytes from the blood of preterm neonates, term neonates , and adults were isolated immunologically by ''negative panning'' and subsequently stimulated with interleukin-1alpha (IL-1alpha), tumor ne crosis factor alpha (TNF-alpha), or lipopolysaccharide (LPS), after wh ich IL-8 levels in the supernatants were measured by ELISA. Total cell ular RNA was extracted and IL-8 mRNA was assessed by Northern blotting and by competitive polymerase chain reaction (PCR) analyses. After st imulation with IL-1alpha, IL-8 accumulation was lowest in supernatants of monocytes from preterm neonates, intermediate in supernatants of m onocytes from term neonates and greatest from monocytes of adults. Sim ilarly, when stimulated with TNF-alpha or LPS, monocytes from preterm neonates produced less IL-8 than cells from term neonates and adults. These differences in IL-8 concentrations paralleled differences in IL- 8 mRNA expression.