IL-2 RECEPTOR GENE-EXPRESSION AND IL-2 PRODUCTION BY HUMAN PRETERM NEWBORNS CELLS

IL-2 receptor (IL-2R) gene expression in human umbilical cord blood mo nonuclear cells (CBMC) of preterm and term newborns was examined follo wing stimulation for 18 h with phytohaemagglutinin (PHA) and compared with that of adult peripheral blood mononuclear cells (PBMC; mothers a nd control group). mRNA for IL-2R could not be detected in CBMC of pre term infants, whereas the mRNA levels for IL-2R found in full term neo nates were similar to those observed in PBMC of adults. IL-2 activity in conditioned medium (CM) of mononuclear cells stimulated with either optimal or suboptimal PHA concentrations for 24 h and 48 h was also d etermined. At 24 h of stimulation, IL-2 activity found in CM obtained from CBMC of preterm and term newborns was significantly higher than t hat found in CM of adults' PBMC. A further enhancement of IL-2 activit y (six to eight times) was observed in CM of preterm and term cells st imulated for 48 h, whereas no significant difference was found in IL-2 activity in CM from adult cells tested at the two incubation periods. The present findings may provide an additional explanation for the im paired function of the immune system, and the high susceptibility to i nfections observed in preterm newborns.