OBJECTIVE: To evaluate age-related differentiation of immune response in newborns by measuring serum concentrations of interleukin-2 (IL-2), interleukin-4 (IL-4) and interferon-γ (IFN-γ) during the perinatal period.Subjects and methods: Fifty-seven healthy term neonates, their mothers and 25 healthy adults (controls) age-matched to the mothers were included in the study. Cytokine concentrations were measured in the umbilical cord (UC), and in first-day (1N) and fifth-day (5N) neonatal samples, compared with those in maternal serum (MS) and control serum samples.Results: Serum IL-2 concentrations in the UC were markedly elevated compared with those in MS and controls (p<0.0001), decreasing significantly thereafter up to 5N (p<0.001). IL-4 serum concentrations did not differ significantly between the UC, 1N and 5N samples; they were, however, markedly elevated compared with those in MS (p<0.001, p<0.0007 and p<0.0001, respectively) and controls (p<0.05, p<0.01 and p<0.006, respectively). IFN-γ serum concentrations were significantly lower in the UC compared with those in controls (p<0.04), increasing significantly up to 5N (p<0.03). Both IFN-γ/IL-2 and IFN-γ/IL-4 ratios increased significantly in 5N, compared with those in the UC (p<0.001 and p<0.03).Conclusion: Our findings indicate a differential cytokine balance at birth with enhanced expression of IL-2 and IL-4 against IFN-γ. However, a regularization of immune response seems to proceed quickly during the early neonatal life.
