Differential development of type 1 and type 2 cytokines and β-chemokines in the ontogeny of healthy newborns

Interleukin (IL)-2, interferon gamma (IFN-γ; type 1 cytokines), IL-4, and IL-10 (type 2 cytokines), and β-chemokines (MIP-1α and RANTES) production by cord blood lymphocytes (CBL) and peripheral blood lymphocytes (PBL) of newborns was analyzed in a cross-sectional study to examine the maturation of these components of the immune response. Immunophenotyping was performed on the same specimens. Results showed that the CD4/CD8 ratio remains stable, the percentage of natural killer cells decreases, and the number and percentage of B cells increase after birth. Analysis of cytokine production suggested that the production of all cytokines increases gradually and steadily after birth, and that IFN-γ and IL-10 production is reduced at birth whereas IL-2 and IL-4 production is not. Finally, mitogen-stimulated β-chemokine production was present at birth and increased slightly but significantly with age. These data indicate that a differential functional maturation of immune response after birth favoring a more precocious development of IL-2 (a type 1 cytokine) is present and should help to analyze the ontogeny of the immune system.