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EAACI Symposium on Epithelial Barriers, Microbiome and Planetary Health 2026

The Epithelial Barrier Theory is a comprehensive explanation for the global, epidemic-level rise in chronic health conditions over the past 65 years. The theory, postulated by Akdis, proposes that exposure to toxic substances introduced by industrialization and modern lifestyle changes disrupts the epithelial barrier of the skin, upper and lower airways, and gut mucosa and causes microbial dysbiosis triggering an inflammatory immune response that can initiate or aggravate more than 70 chronic inflammatory diseases. The Epithelial Barrier Theory includes the ONE HEALTH concept with the strong veterinary medicine involvement of pets and domestic animals.

Epithelial Barrier Theory in Lectures

The epithelial barrier theory and its associated diseases
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Sun N, Ogulur I, Mitamura Y, et al.

Epithelial barrier dysfunction and associated diseases in companion animals: Differences and similarities between humans and animals and research needs

Ardicli S, Ardicli O, Yazici D, et al.

Epithelial barrier theory in the context of nutrition and environmental exposure in athletes

Kistler W, Villiger M, Villiger B, et al.

Latest Publications

Common Food Emulsifiers Impair Epithelial Barrier Integrity and Trigger Pro-Inflammatory Responses and IgE Production

D. Yazici, Y. Hayashi, Y. Pat, et al.

The global rise in allergic and autoimmune diseases since the 1960s has been associated with environmental disruptions of epithelial barriers, particularly in the gastrointestinal tract. Among the implicated factors are food emulsifiers, which have become increasingly prevalent in processed foods such as peanut butter. This study investigates the biological effects of two commonly used food emulsifiers in peanut butter, soy lecithin and diacetyl tartaric acid esters of mono- and diglycerides (DATEM), on gastrointestinal tissue responses and immune responses using advanced in vitro gut-on-a-chip models, human adult stem cell-derived colon organoids-on-a-chip, and murine models. Both emulsifiers induced dose-dependent cytotoxicity and disrupted epithelial barriers, as demonstrated by reduced transepithelial electrical resistance and disorganization of zona occludens-1 at daily-exposure doses.

Understanding the Type 2 Immunity: An Evolving View Beyond Allergic Diseases

R. Jiménez-Saiz, S. Iborra, C. Blanco, et al.,

Type 2 (T2) immunity is classically associated with defense against helminths and environmental threats, from a physiological perspective, and with allergies and eosinophilic inflammatory diseases, in a pathological sense. However, growing evidence reveals that T2 pathways also support other essential homeostatic functions, including tissue protection and repair. There are major clues from the early evolution of T2 responses for protection against massive tissue damage and positive selection for survival against parasites starting over 500 million years ago. These responses likely co-evolved stepwise with immune-regulatory circuits, culminating in the emergence of the fully functional human-type IgG4 in the great apes (Hominidae) within the last ~10 million years.

Lectures

Epithelial Barrier Theory in 9 Lectures

Publications

Key publications

Public Information

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The Epithelial Barrier Theory is a comprehensive explanation for the global, epidemic-level rise in chronic health conditions over the past 65 years. The theory, postulated by Akdis, proposes that exposure to toxic substances introduced by industrialization and modern lifestyle changes disrupts the epithelial barrier of the skin, upper and lower airways, and gut mucosa and causes microbial dysbiosis triggering an inflammatory immune response that can initiate or aggravate many chronic inflammatory diseases.

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