Induction of inflammation as a possible mechanism of probiotic effect in atopic eczema-dermatitis syndrome

Background: The immunomodulating mechanisms of Lactobacillus GG (LGG) and other probiotics are poorly understood. Objective: We studied in vivo the immunologic effects of probiotics in infants with atopic eczema-dermatitis syndrome (AEDS) and cow's milk allergy (CMA). Methods: Two hundred thirty infants with AEDS and suspected CMA received, concomitant with elimination diet, either LGG, a mixture of 4 probiotic strains (MIX), or placebo for 4 weeks. All available paired pretreatment and posttreatment plasma samples (n = 132) were analyzed for concentrations of IL-2, 1L-4, IL-6, IL-10, TNF-alpha, IFN-gamma, soluble intercellular adhesion molecule 1, soluble E-selectin, TGF-beta 1, TGF-beta 2, and C-reactive protein. Results: In infants with IgE-associated AEDS, treatment with LGG induced higher C-reactive protein levels than in the placebo group (geometric mean, 0.83 mu g/mL [95% Cl, 0.560.81] vs 0.42 mu g/ml, [95% Cl, 0.27-0.65], P=.021). Concomitantly, IL-6 levels increased after treatment with LGG (P=.023) but not with MIX or placebo. Soluble E-selectin levels were higher after probiotic than after placebo treatment in infants with IgE-mediated CMA (LGG geometric mean, 86.7 ng/mL [95% Cl, 75.2-100]; MIX geometric mean, 91.6 ng/ml, [95% CI, 74.8-111.9]; and placebo geometric mean, 64.9 ng/ml, [95 % Cl, 53-79.3], analysis of covariance, P=.035; LGG vs placebo, P=.023; MIX vs placebo, P=.020). Use of MIX induced an increase in plasma IL-10 levels (P=.016). Conclusion: Probiotics induced systemically detectable low-grade inflammation, which might explain the clinical effects of probiotics in AEDS and CMA.