Can microbiota prevent peanut allergy?
Patients who go on to develop a peanut allergy may have a specific microbial signature even before the allergy manifests, starting from their very first months of life.
About this article
A growing body of research is pointing to the existence of distinct microbiotic signatures for different food allergies. This field of research is helping to position the microbiota as a central player in the development of such allergies. A new longitudinal study published recently in the Journal of Allergy & Clinical Immunology has shed new light on possible links between the onset of a peanut allergy and microbiota.
As this allergy generally develops during infancy, the researchers studied the microbiota of children at risk of developing a peanut allergy at the age of 10 months (SD: 3.1), then at 9 years (SD: 0.6). Within this population, 35 (28.7%) of the children developed a peanut allergy before the age of 9.
A different gut microbiota signature from the very first months of life
These 35 children in the PA (Peanut Allergy) group had a less diverse microbiota at inclusion (p=0.014) than the NPA (Non-Peanut Allergy) group. Their microbiota diversified with age, while that of the NPA group remained stable.
At age 9, both groups showed a comparable microbiotic diversity.
At inclusion, the PA group had a higher proportion of Clostridium sensu stricto 1 sp, while Streptococcus sp was more prevalent in the NPA group. By the age of 9, the relative abundance of these two species was normal in both populations. Conversely, the abundance of the Bifidobacterium sp species dropped in the PA group and even became higher in the NPA population.
Allergy development is identified as being associated with altered levels of 139 metabolites in the metabolome (FDR ≤ 0.05).
These metabolites are associated with a histidine metabolism pathway (FDR = 0.037, pathway impact = 0.28).
Six short-chain fatty acids were studied in particular. The butyrate and isovalerate levels dropped in the PA group, while the isovalerate level remained stable in the NPA group with an increase in butyrate.
Is there a pathophysiological mechanism of peanut allergy?
The authors speculate that the lower microbiota diversity in PA infants may suggest that they have less stable gut communities during this phase of rapid immune system development.
The reduced relative abundance of Bifidobacterium sp, known for its use as an anti-allergy probiotic and for inducing mast cell apoptosis in mice, could also play a role in the development of allergies.
The authors also note that the micro-organisms present in the gut of children predisposed to developing this allergy species capable of producing metabolites originating from the histidine metabolism pathway, the precursor of histamine, the effector characteristic of allergic reactions.
This study therefore advances our understanding of the close links between microbiota and allergy, and raises the question of the possible benefits of gut microbiota supplementation in preventing PA.
1. Chun Y, Grishin A, Rose R, Zhao W, Arditi Z, Zhang L, Wood RA, Burks AW, Jones SM, Leung DYM, Jones DR, Sampson HA, Sicherer SH, Bunyavanich S. Longitudinal dynamics of the gut microbiome and metabolome in peanut allergy development, Journal of Allergy and Clinical Immunology (2023). DOI: 10.1016/j.jaci.2023.08.012