Substantial evidence that alterations in the gut microbiome early in life “imprint” gut mucosal immunity, which is probably important for development of food allergy.

Maternal factors, timing and how solids introduced all likely to be important.

Similarly, the “exposome” is the term for external factors influencing epithelial barrier immune balance – damage, inflammation, colonization, dysbiosis, translocation etc.

Great data from studies of Hutterite vs Amish populations in the US (same origin in Austria) – Amish are more traditional farmers, low technology use, v low atopy rates. See more on the farm effect on allergy here.

Transplacental factors discussed by Patrick Holt (Perth, WA) in 2009 (“soothing signals”).

MV130 is heat inactivated cocktail of bacteria – in RCT (n=120, under 3yrs) 6 months SLIT reduces episodes of recurrent wheeze by 40% in children, also lower duration and symptom scores. [Antonio Nieto, Madrid]

COVID 19 has shown how innate immunity isn’t actually fixed, and can be trained (“trained immunity”) esp BCG, LPS.

Experimental studies have shown that faecal transplants or other attempts to modify bacterial commensals can prevent or treat food allergy as well as asthma.

Mechanisms include restoration of gut immune regulatory checkpoints (eg retinoic orphan receptor gamma T+ regulatory T cells), the epithelial barrier, and healthy immunoglobulin A responses to gut commensals.

[Rima Rachid, JACI 2021]