The effect of dexamethasone (DEX) on interleukin (IL)-10 and IL-12p40 production was examined in preterm newborns, term infants and was compared to that in adults. Mononuclear cells isolated from newborn cord blood (CBMC) and peripheral blood from adults (PBMC) were incubated with lipopolysaccharide in the absence or presence of DEX at concentrations between 10^–8 and 10^–5 M. Cytokine concentration in the supernatants was tested using ELISA kits. DEX induced a dose-dependent inhibition of IL-10 production by PBMC from adults whereas CBMC from newborns were mostly unaffected by the drug. DEX caused a dose-dependent inhibition of IL-12p40 secretion by cells of the three age groups, although to a different extent. Since IL-12 plays a critical role in the development of a protective immune response to fungal infection, it is conceivable that the inhibition of IL-12p40 secretion caused by DEX may contribute to the increased occurrence of fungal infections in preterms treated with this drug.

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