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Friday, October 1, 2010

New evidence relates prebiotics to reduced occurrence of AD

The jury is still out on whether supplementation with active prebiotics favorably affects atopic conditions, in particular, atopic dermatitis (AD) and food allergies, in children and adults. This question is becoming increasingly relevant as more and more research is showing that our gut microbiota differs significantly from what is considered to be the primitive state.

Noting that more cases of atopy are associated with children who have little or no familial risk, Grüber et al in this issue investigate the effects of immunoactive, pre-biotic oligosaccharides (OS) added to formula on weaned infants with low atopic risk. The authors created a cow’s milk formula with OS that was very similar to breast milk. Three groups were followed: a group of infants receiving pre-biotic formula (PG), a group receiving formula with no added OS (CG), and an exclusively breastfed group (BG).

The authors report that the incidence of AD in PG infants at the first birthday was reduced 44% as compared to CG infants. This rate was much closer to that of the breastfed group. Severity as measured by TARC levels did not differ between the three groups at the first birthday. Grüber et al. also report that milk and egg specific IgE was not affected, implying that pre-biotic supplementation did not alter sensitization.

Finally, Grüber et al. comment that it would be an important public health issue to know if this effect is persistent. They suggest that it does and could result in reduced respiratory allergy in later life.

We asked Dr. Grüber about the implications of this study:

JACI: Given your results on serum levels of TARC in infants that remained free of AD at their first birthday, please comment about the usefulness of TARC as a biomarker of severity in atopic dermatitis.

Dr. Christoph Grüber: TARC (Thymus- and activation-regulated chemokine) is a Th2-type chemotactic messenger which is upregulated during eczema exacerbation in the blood and which recruits inflammatory cells to the eczematous skin. TARC has been found useful as a biomarker for moderate to severe inflamed skin. Most affected infants in our study had mild eczema. TARC may discriminate non-afflicted and mildly afflicted cases less well.

Do you have any questions for the authors, or comments about this study? We want to hear from you. Please feel free to post your own questions or comments. All questions and comments will be forwarded to the authors for a response.

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