Facultad de Medicina

Purpose of Review Allergic diseases have become a burden in industrialized societies. Among children, food allergy (FA) constitutes a major impairment of quality of life. FA is partly due to a lack or loss of tolerance to food antigens at the level of the intestinal mucosa, where the microbiota plays a crucial role. Early changes in the composition of the gut microbiota may influence the development of the immune system and can be related to the risk of allergic diseases, including FA. This review will focus on the role of sphingolipids and the major bacteria involved in their metabolism, in the development of food antigen sensitization and FA. Recent Findings Numerous studies have identified different patterns of microbial composition between individuals with and without FA, pointing to an interaction between gut microbiota, enterocytes, and immune cells. When this interaction is lost and an imbalance in the composition of the intestinal microbiota occurs, the integrity of the epithelial barrier may be altered, leading to intestinal permeability and sensitization to food antigens and the development of FA. Gram- negative bacteria, especially those of the Proteobacteria phylum, have been associated with the development of FA. Investigating the interactions between the intestinal microbiota and the immune system, their influence on intestinal barrier function, and their production of metabolites and signaling molecules may contribute to understanding the pathogenesis of FA. Summary Sphingolipids, a class of bioactive amphipathic lipids found in cell membranes, have emerged as critical regulators of inflammation. In this review, we will attempt to summarize the existing knowledge on the role of these molecules and the major bacteria involved in their metabolism in the mechanisms underlying sensitization to food antigens and the development of FA.

Allergic diseases, such as respiratory, cutaneous, and food allergy, have dramatically increased in prevalence over the last few decades. Recent research points to a central role of the microbiome, which is highly influenced by multiple environmental and dietary factors. It is well established that the microbiome can modulate the immune response, from cellular development to organ and tissue formation exerting its effects through multiple interactions with both the innate and acquired branches of the immune system. It has been described at some extent changes in environment and nutrition produce dysbiosis in the gut but also in the skin, and lung microbiome, inducing qualitative and quantitative changes in composition and metabolic activity. Here, we review the potential role of the skin, respiratory, and gastrointestinal tract (GIT) microbiomes in allergic diseases. In the GIT, the microbiome has been proven to be important in developing either effector or tolerant responses to different antigens by balancing the activities of Th1 and Th2 cells. In the lung, the microbiome may play a role in driving asthma endotype polarization, by adjusting the balance between Th2 and Th17 patterns. Bacterial dysbiosis is associated with chronic inflammatory disorders of the skin, such as atopic dermatitis and psoriasis. Thus, the microbiome can be considered a therapeutical target for treating inflammatory diseases, such as allergy. Despite some limitations, interventions with probiotics, prebiotics, and/or synbiotics seem promising for the development of a preventive therapy by restoring altered microbiome functionality, or as an adjuvant in specific immunotherapy.