Feeding a formula supplemented with long chain polyunsaturated fatty acids modifies the "ex vivo" cytokine responses to food proteins in infants at low risk for allergy

Abstract

Long chain polyunsaturates (LCP) status during the early neonatal period is associated with a reduced risk of atopic symptoms and later allergies. In this study, we characterized the immune response of low-risk, term, formula-fed infants randomized at <or=14 d of age to standard term formula (Formula) or formula containing LCP (Formula+LCP) for 4 wks. Infants exclusively fed human milk were included for comparison. Peripheral blood was collected at 14 and 42 d of age, and lymphocyte phenotype, proliferation, and cytokine production (IL-2, IL-4, IL-6, IL-10, IL-12, IFN-gamma, TNF-alpha, TGFbeta) were assessed after incubation with beta-lactoglobulin (BLG) and soy protein (SOY). Lymphocyte proliferation did not differ between groups. Compared with human milk-fed infants at 2 wks, formula-fed infants produced more TNF-alpha and IFN-gamma and had more cells expressing ICAM-1 (CD54) after incubation with BLG and SOY (p < 0.05). At 6 wks of age, infants fed Formula+LCP produced more TNF-alpha with SOY (3.2-fold) and IFN-gamma (3.3-fold) with BLG compared with infants fed Formula (p < 0.05). In conclusion, low-risk term infants fed formula before 14 d of age produced more TNF-alpha and IFN-gamma in response to food proteins. Feeding Formula+LCP for 4 wks maintained the higher TNF-alpha and IFN-gamma response to these food proteins.