Cow’s milk is one of the most common allergens affecting young children. In many patients the allergy resolves by late childhood, but it is unclear what factors determine if and when a child will develop diary tolerance. In this study, the authors investigate whether the gut microbiome plays a role in the development of dairy tolerance in children.
First, the researchers selected a cohort of 226 milk-allergic children between 3- and 16-months old and performed high-throughput sequencing on their gut microbiota. Then, they followed up with these patients each year until age 8; by this time, 56.6% of the patients’ milk allergies had resolved. They found that gut microbiome composition at 3-6 months had a significant association with milk allergy resolution by age 8, but that among patients whose microbiomes had been sampled at ages 7-16 months there was no association with allergy outcomes. Specifically, among subjects tested at 3-6 months, those whose microbiomes contained more species within the Firmicutesphylum and Clostidiaclass were more likely to see allergy resolution by 8 years. On the other hand,Bacteriodetesand Enterobacterbacteria were associated with allergy persistence. In addition, those patients whose allergies resolved by age 8 tended to have more diverse microbiome composition and lower levels of microbial fatty acid metabolism than those whose allergies did not resolve.
This study provides multiple insights with therapeutic potential. For example, if other studies can confirm the association of certain bacterial phyla with food allergy resolution, an infant’s microbiome could be used to assess the likelihood of future allergy persistence; in addition, probiotic supplements could be used to bolster a child’s chance of recovering from the food allergy. Bacterial fatty acid pathways are also possible therapeutic targets: decreased fatty acid metabolism in gut microbiota could potentially reduce risk of allergy persistence, so reduction of inflammation that results from these pathways could help promote dairy allergy resolution. Finally, the finding that microbiome composition was associated with food allergy resolution only the youngest cohort suggests that early life diet and environment have an essential effect on future immune activity.
By: Zach Altshuler
Bunyavanich, S. et al.Early-life gut microbiome composition and milk allergy resolution. J. Allergy Clin. Immunol.138, 1122–1130 (2016).