No detectable beneficial systemic immunomodulatory effects of a specific synbiotic mixture in infants with atopic dermatitis

Background In a murine model of allergic inflammation, Bifidobacterium breve M-16V has been shown to reduce IL-4 and IgE by inducing IL-10 and IFN-gamma. However, it remains unknown whether this strain has the same effect in humans with allergic disease. Objective To determine the effects of Bifidobacterium breve M-16V combined with a prebiotic oligosaccharide mixture (synbiotic) on atopic markers, ex vivo cytokine production by peripheral blood mononuclear cells (PBMCs) and circulating regulatory T cell percentage in infants with atopic dermatitis. Methods In a double-blind, placebo-controlled multi-centre trial, 90 infants with atopic dermatitis, age < 7 months, were randomized to receive an infant formula with Bifidobacterium breve M-16V and a mixture of short chain galactooligosaccharides and long chain fructooligosaccharides (Immunofortis (R)), or the same formula without synbiotics during 12 weeks. At week 0 and 12, plasma levels of IL-5, IgG1, IgG4, CTACK and TARC, ex vivo cytokine responses by PBMCs and percentage of regulatory T cells, were determined. Results There were no significant differences between the synbiotic and the placebo group in IL-5, IgG1, IgG4, CTACK and TARC levels and ex vivo cytokine production by antiCD3/anti-CD28-stimulated PBMCs. With allergen-specific stimuli, we found a decreased IL-12p40/70 and IL-12p70 production in response to egg allergen (P = 0.04 and P = 0.01, respectively) and decreased IL-12p70 production in response to peanut allergen (P = 0.003) in the synbiotic compared with the placebo group. Circulating regulatory T cell percentage did not significantly differ between the groups. Conclusions and Clinical Relevance This synbiotic mixture has no detectable effect on plasma levels of the analysed atopic disease markers, ex vivo cytokine production and circulating regulatory T cell percentage in infants with atopic dermatitis, besides down-regulation of IL-12 production in egg-and peanut-stimulated PBMCs. These results do not support the use of this synbiotic in clinical practice.