Maturation of cytokine‐producing capacity from birth to 1 yr of age

Little is known about the immunologic maturation in the early stages of life. The aim of this study was to investigate maturation of immune system from birth to 1 yr of age and to compare immune functions between mothers and their children. Also the effect of atopy to the immune responses of children was examined. Cord blood samples (n = 228) and peripheral blood samples of children (n = 200) and their mothers (n = 208) 1 yr after birth were collected. Whole blood samples were stimulated for 24 and 48 h with Staphylococcal enterotoxin B (SEB), lipopolysaccharide (LPS) and the combination of phorbol ester and ionomycin (P/I). Production of TNF‐α, IFN‐γ, IL‐5, IL‐8 and IL‐10 was determined using ELISA. Significant mother‐to‐child correlation was detected in cytokine‐producing capacity at the age of 1 yr. TNF‐α (P/I, SEB and LPS stimulation), IFN‐γ (P/I and SEB), IL‐5 (P/I and SEB) and IL‐10 (P/I, SEB and LPS) producing capacity increased from birth to 1 yr of age. In general, stimulated cytokine responses were higher in mothers’ than in children’s blood samples, except in the case of P/I and LPS‐stimulated IL‐8, which were highest at birth. Maternal inhalation atopy was associated with increased cord blood IL‐5 (24 and 48 h) and IL‐10 (48 h) production following P/I stimulation. Also children of food atopic mothers expressed elevated cord blood IL‐10 (48 h, P/I) responses and decreased IFN‐γ/IL‐5 ratio (24 h, P/I). In addition, the production of IFN‐γ (24 and 48 h, P/I) and the IFN‐γ/IL‐5 ratio (24 h and 48 h, P/I) at the age of 1 yr was lower among children with food atopic mothers. In conclusion, our results suggest that both adaptive and innate immune responses increase from birth to 1 yr of age, but are still weak in comparison to adult responses. Cytokine responses of children begin to correlate with those of their mothers during the first year of life. Although only few associations were observed between atopy and cytokine‐producing capacity, our results suggest that children of atopic mothers express T_h2‐polarized cytokine pattern.