Lactobacillus GG effect in increasing IFN-γ production in infants with cow's milk allergy

Background: Probiotic bacteria are potentially beneficial to maturation of the infant's immune system. Objective: To examine the role of probiotic bacteria in treatment of cow's milk allergy (CMA) and IgE-associated dermatitis, we investigated the immunologic effects of Lactobacillus rhamnosus GG (LGG) and a mixture of 4 bacterial species (MIX). Methods: In a randomized, double-blind study design, concomitantly with elimination diet and skin treatment, LGG, MIX, or placebo was given for 4 weeks to infants with suspected CMA. After anti-CD3 (OKT3) and anti-CD28 stimulation of PBMCs, IFN-gamma, IL-4, IL-5, and IL-12 levels were measured in culture supernatants by ELISA. Intracellular IFN-gamma, IL-4, and IL-5 production on CD4 lymphocytes was analyzed with fluorescence-activated cell sorting. Results: Secretion of IFN-gamma by PBMCs before the treatment was significantly lower in infants with CMA (P = .016) and in infants with IgE-associated CMA (P = .003) than in non-CMA infants. Among the infants who received LGG, the level of secreted IFN-gamma increased in those with CMA (P = .006) and in those with IgE-associated dermatitis (P = .017) when compared with the placebo group. Secretion of IL-4 increased significantly in infants with CMA in the MIX (P = .034) but not in the LGG group. Conclusion: Deficiency in IFN-gamma response appears to be related to CMA. LGG raises IFN-gamma production of PBMC in infants with CMA and in infants with IgE-associated dermatitis and may thus provide beneficial T(H)1 immunomodulatory signals. MIX, although containing LGG, appears to modulate the immune responses differently.