The Role of the Gut Microbiome in Immune Regulation and Autoimmune and Allergic Diseases: Implications of Probiotics, Prebiotics, and Fecal Microbiota Transplantation

Abstract

Autoimmune and allergic diseases are systemic 
conditions caused by immune dysregulation, affecting 
millions globally. Autoimmune disorders, such as 
rheumatoid arthritis and systemic lupus erythematosus, 
involve autoreactive lymphocytes attacking host 
tissues, while allergic diseases like asthma and atopic 
dermatitis stem from exaggerated immune responses to 
environmental antigens. Emerging evidence highlights 
the critical role of the gut microbiome in maintaining 
immune homeostasis and its dysregulation (dysbiosis) 
in the pathogenesis of these diseases. This systematic 
review, adhering to PRISMA 2020 guidelines, examined 
studies published in the last decade to explore 
microbiota-mediated immune regulation and the 
therapeutic potential of probiotics, prebiotics, and fecal 
microbiota transplantation (FMT). A total of 145 records 
were identified, with 16 studies meeting inclusion 
criteria after rigorous screening and quality assessment. 
Results reveal that dysbiosis, marked by reduced 
microbial diversity and shifts in bacterial composition, 
contributes to immune dysfunction and disease 
progression. Probiotics and prebiotics were shown to 
enhance regulatory T-cell activity, restore gut barrier 
integrity, and reduce inflammatory cytokines, while FMT 
demonstrated efficacy in conditions such as ulcerative 
colitis and type 1 diabetes, improving clinical outcomes. 
Despite promising short-term results, challenges 
including variability in methodologies, accessibility, and 
long-term safety remain. This review highlights the gut 
microbiome as a crucial therapeutic target in 
autoimmune and allergic diseases. Integrating 
microbiome-based interventions with personalized 
approaches could revolutionize immune regulation and 
disease management, paving the way for innovative, 
accessible, and effective treatment strategies to 
improve patient outcomes worldwide.