The Microbial Role in Allergy: A Comprehensive Review

Abstract

Background: The rise in allergic diseases in Western industrial nations has been paralleled by an increased understanding of the intricate relationship between microbial exposure and immune system responses. The hygiene hypothesis suggests a link between reduced exposure to infectious agents and an increase in allergies, emphasizing the need for a deeper investigation into the roles of various microbes in allergic reactions. Objective: This review aims to elucidate the complex mechanisms underlying allergic reactions, specifically focusing on the roles of parasites, bacteria, fungi, and viruses. It seeks to explore the potential of microbial exposure as both a protective and pathogenic factor in the development of allergies, with an eye towards informing future therapeutic strategies. Methods: An extensive literature review was conducted using databases such as Google Scholar, Scopus, PubMed, and Web of Sciences, focusing on studies published up to March 2024. The review synthesized findings on the impact of microbial exposure on allergic diseases, examining the roles of specific microbes, their interaction with the immune system, and the implications for allergic responses. Results: The review highlights the dual nature of microbial exposure in allergies, with some microbes offering protection against allergic diseases through the modulation of immune responses, while others exacerbate allergic conditions. Notably, probiotics and certain parasitic infections demonstrate potential in modulating the immune system to prevent or reduce allergic responses. Conversely, specific bacterial, fungal, and viral exposures are linked to the exacerbation of allergic diseases. Conclusion: Understanding the complex relationship between microbial exposure and allergic diseases is crucial for developing novel therapeutic and preventive strategies. This review underscores the potential of targeted microbial management in modulating immune responses to allergens, suggesting a promising avenue for reducing the global burden of allergic diseases.