Lactobacillus GG treatment during pregnancy for the prevention of eczema: a randomized controlled trial.

BACKGROUND: Probiotic supplementation in early life may be effective for preventing eczema. Previous studies have suggested that prenatal administration may be particularly important for beneficial effects. OBJECTIVE: We examined whether prenatal treatment with the probiotic Lactobacillus rhamnosus GG (LGG) can influence the risk of eczema during infancy. METHODS: We recruited 250 pregnant women carrying infants at high risk of allergic disease to a randomized controlled trial of probiotic supplementation (LGG 1.8 × 10(10) cfu/day) from 36 weeks gestation until delivery. Infants were assessed during their first year for eczema or allergic sensitization. Immunological investigations were performed in a subgroup. Umbilical cord blood was examined for dendritic cell and regulatory T cell numbers and production of TGFß, IL-10, IL-12, IL-13, IFN-γ and TNFα. Maternal breast milk was examined for total IgA, soluble CD14 and TGFß. RESULTS: Prenatal probiotic treatment was not associated with reduced risk of eczema (34% probiotic, 39% placebo; RR 0.88; 95% CI 0.63, 1.22) or IgE-associated eczema (18% probiotic, 19% placebo; RR 0.94; 95% CI 0.53, 1.68). Prenatal probiotic treatment was not associated with any change in cord blood immune markers, but was associated with decreased breast milk soluble CD14 and IgA levels. CONCLUSIONS: Prenatal treatment with Lactobacillus rhamnosus GG was not sufficient for preventing eczema. If probiotics are effective for preventing eczema, then a postnatal component to treatment or possibly an alternative probiotic strain is necessary.

gammaH2AX: a sensitive molecular marker of DNA damage and repair.

Phosphorylation of the Ser-139 residue of the histone variant H2AX, forming gammaH2AX, is an early cellular response to the induction of DNA double-strand breaks. Detection of this phosphorylation event has emerged as a highly specific and sensitive molecular marker for monitoring DNA damage initiation and resolution. Further, analysis of gammaH2AX foci has numerous other applications including, but not limited to, cancer and aging research. Quantitation of gammaH2AX foci has also been applied as a useful tool for the evaluation of the efficacy of various developmental drugs, particularly, radiation modifying compounds. This review focuses on the current status of gammaH2AX as a marker of DNA damage and repair in the context of ionizing radiation. Although the emphasis is on gamma-radiation-induced gammaH2AX foci, the effects of other genotoxic insults including exposure to ultraviolet rays, oxidative stress and chemical agents are also discussed.

Reduced membrane bound CD14 expression in the cord blood of infants with a family history of allergic disease.

BACKGROUND: Infants at increased risk of allergic disease have altered immune function at birth, but the specific immune changes described differ between studies and their precise nature is not well defined. Changes affecting innate immune responses may be particularly important in allergic disease pathogenesis. OBJECTIVE: We investigated whether inherited risk of allergic disease is associated with altered markers of innate immunity, T cell regulation or dendritic cell (DC) percentage in human newborns. METHODS: Cord blood was collected from infants at low risk (no parent affected by allergic disease, n=14), intermediate risk (one affected parent, n=54) or high risk (two affected parents, n=25) of developing allergic disease. Cord blood mononuclear cells were cultured with ovalbumin (OVA), lipopolysaccharide, lipoteichoic acid (LTA), heat-killed lactobacillus, alpha-CD3 or medium alone. Cells were analysed by flow cytometry for expression of CD14, FoxP3 and DC percentage, and by real-time RT-PCR for TLR2 and TLR4 expression in infants at intermediate or high risk of allergic disease. RESULTS: Infants at high risk of allergic disease had reduced percentage of CD14(+) monocytes (P=0.01) and reduced CD14 mean fluorescence intensity (P=0.01) in uncultured mononuclear cells. They also had decreased DC percentage in mononuclear cells cultured with OVA (P=0.04), lipopolysaccharide (P=0.01), LTA (P=0.02) and alpha-CD3 (P=0.03) as compared with infants at intermediate or low risk of allergic disease. No relationship was seen between risk of allergic disease and TLR2 or TLR4 expression, or FoxP3 expression in cultured cells. CONCLUSIONS: Infants with a biparental history of allergic disease have altered markers of innate immunity at birth, with reduced expression of membrane bound CD14 and consequently reduced in vitro development of DCs. Further work is needed to understand the role that these alterations play in the pathogenesis of allergic disease, and whether interventions to up-regulate fetal CD14 expression can prevent allergic disease.

Effects of Lactobacillus GG treatment during pregnancy on the development of fetal antigen-specific immune responses.

BACKGROUND: Several clinical trials suggest that probiotics may have a role in the prevention of eczema. The optimal timing and mechanisms underlying this intervention are not clear. In particular it is not known whether such treatment works during pregnancy or whether postnatal exposure is important. OBJECTIVE: We investigated whether the probiotic Lactobacillus rhamnosus strain GG (LGG) influences fetal immune responses when administered to pregnant women, as a possible mechanism for its protective effects against the development of eczema. METHODS: Peripheral blood mononuclear cell from 11 adults treated with LGG, and cord blood mononuclear cells (CBMCs) from 73 women participating in a randomized controlled trial of LGG treatment were cultured with heat-killed LGG, ovalbumin (OVA) or without stimulus. Cells were analysed by flow cytometry and real-time PCR for markers of dendritic cell (DC) phenotype, T cell proliferation and regulation. Cytokine secretion was analysed in culture supernatants by multiplex cytokine assay. RESULTS: LGG treatment of adults led to systemic immune responses suggestive of antigen-specific tolerance including reduced CD4(+) T cell proliferation to heat-killed LGG (30% reduction; P=0.03). LGG treatment of pregnant women did not influence CD4(+) T cell proliferation, forkhead box P3 expression, DC phenotype or cytokine secretion in CBMCs cultured with heat-killed LGG or OVA. CONCLUSION: LGG treatment of pregnant women fails to influence fetal antigen-specific immune responses. This suggests that modulation of fetal immune responses may not be a major mechanism by which probiotics such as LGG prevent eczema.