The aim of this study was to profile the changes in intracellular and plasma cytokines during the neonatal period and evaluate the impact of breast feeding on these parameters. For this purpose, we measured the interleukin (IL)-2 and IL-4 producing CD3+/CD69+ T-cells using flow cytometry and plasma concentrations of interferon (IFN)-gamma and IL-4 using ELISA, in 122 healthy term neonates, aged 6-12 h, born to non-atopic parents, and 25 healthy children aged 1-12 years. A total of 42/122 neonates exclusively breast-fed (BF) and 39/122 formula fed (FF) were studied again on the 30th day of life for the above parameters. Finally, a clinical evaluation for the presence of atopic disease was conducted at 2 years of age. We found that at birth, the percentage of CD3+/CD69+/IL-4+ T-cells (median = 15.8%, range = 4.4%-49%) and plasma concentrations of IL-4 (median = 0.22 pg/ml, range = 0.18-0.25 pg/ml) were significantly higher (P<0.0001) compared to those of children (median = 1.6%, range = 0.16%-2.7% for CD3+/CD69+/IL-4+ and median = 0.17 pg/ml, range = 0.13-0.26 pg/ml for IL-4), whereas plasma concentrations of IFN-gamma were significantly lower in neonates (median = 0.42 pg/ml, range = 0.3-1.5 pg/ml) than in children (median = 1.2 pg/ml, range = 0.3-2.6 pg/ml, P<0.0001). During the neonatal period, only the CD3+/CD69+/IL-4+ T-cells increased significantly in both BF and FF groups. Comparison between BF and FF groups revealed no significant difference in any of the parameters measured. Moreover, no difference in the development of atopy during the first 2 years of life was found between BF and FF infants.Conclusion:
our findings demonstrate that during the entire neonatal period type 2 immunity dominates, regardless of the mode of feeding, whereas type 1 immunity dominates during childhood. Moreover, in the absence of family history of atopy, the mode of feeding per se does not play a crucial role in the development of atopy within the first 2 years of life.