RAGs and BUGS: An alliance for autoimmunity

Area of Science:

• Immunology
• Microbiology
• Genetics

Background:

• Hypomorphic Rag mutations cause Omenn Syndrome (OS), a severe immunodeficiency with autoimmune manifestations.
• The role of environmental factors, particularly gut microbiota, in OS pathogenesis is largely unknown.
• Previous studies in a murine model suggest a significant role for gut microbiota in OS immune dysregulation.

Purpose of the Study:

• To investigate how gut dysbiosis and loss of T cell tolerance to commensals influence OS autoimmunity.
• To explore the mechanisms by which gut-derived factors modulate skin immunity and cutaneous manifestations in OS.
• To understand the broader implications of gut microbes in barrier integrity and host physiology in OS.

Main Methods:

• Analysis of immune responses in a murine model of Omenn Syndrome.
• Investigation of gut microbiota composition and its impact on T cell tolerance.
• Assessment of immune cell activation and cytokine profiles.
• Evaluation of barrier site integrity and skin pathology.

Main Results:

• Gut dysbiosis and loss of T cell tolerance to commensals are linked to autoimmunity in OS.
• Commensal antigens and gut-derived T cells may drive skin immunity and cutaneous lesions in OS.
• These mechanisms contribute to the hallmark hyper-IgE and immune dysregulation seen in OS.

Conclusions:

• Gut microbiota plays a critical role in the pathogenesis of Omenn Syndrome.
• Dysbiosis and impaired T cell tolerance to gut commensals are key drivers of autoimmunity in OS.
• Understanding these gut-microbe interactions is crucial for developing therapeutic strategies for OS and related conditions.