Peripheral Immune Tolerance Mechanisms

Introduction to Peripheral Immune Tolerance

Regulatory T cells (Tregs), including natural Tregs (nTregs) and inducible Tregs (iTregs), play crucial roles in preventing autoreactivity by suppressing autoantigen-specific immune responses, as supported by the American Academy of Allergy, Asthma, and Immunology 1
B regulatory cells (Bregs) inhibit autoreactive B cells that would otherwise produce autoantibodies, according to the American Association for the Study of Liver Diseases 2

Oral tolerance is acquired through interactions between antigen-presenting cells and T cells in gut-associated lymphoid tissue, as noted by the American Academy of Allergy, Asthma, and Immunology 1
Gut microbiota, including beneficial bacteria like Bifidobacterium, Lactobacillus, and Faecalibacterium prausnitzii, strengthen the immune system, reduce inflammation, and promote gut barrier function, as reported by the International Society for Microbial Ecology 3

Genetic factors, such as HLA associations, particularly within the conserved 8.1 ancestral haplotype, predispose individuals to autoimmunity, according to the American Association for the Study of Liver Diseases 2
Exposure to post-translationally modified self-proteins not covered by central tolerance can trigger autoimmune disease, as stated by the Society for Immunotherapy of Cancer 4
Dysregulation of regulatory cells, including failure of Tregs to control autoantigen-specific effector mechanisms, leads to hepatic injury in autoimmune hepatitis, as noted by the American Association for the Study of Liver Diseases 2

A break in self-tolerance occurs when thymic autoantigen-specific nTregs fail to prevent immune responses to self-antigens during exposure to environmental triggers, according to the American Association for the Study of Liver Diseases 2
Antigen presentation by professional antigen-presenting cells to autoreactive T cell receptors contributes to the development of autoimmunity, as reported by the American Association for the Study of Liver Diseases 2

Monitoring immune markers, such as inflammatory biomarkers, requires repeated measurements for intervals ≥6 months, as recommended by the Psychoneuroimmunology Research Society 5
Therapeutic targets, including emerging treatments that aim to modulate regulatory T cells in a disease-specific way, are being developed, as noted by the International Society of Exercise and Immunology 6
Novel approaches, such as low-dose IL-2 infusion to expand autoantigen-specific iTregs, infusion of autoantigen-specific iTregs generated ex vivo, and mesenchymal stem cells to inhibit innate immune cells and effector T cells, are being explored, as reported by the American Association for the Study of Liver Diseases 7

Overlooking secondary immunodeficiency, which can alter immune function, must be ruled out when evaluating immune dysregulation, as stated by the American Academy of Allergy, Asthma, and Immunology 8
Ignoring microbiota influence, which can affect immune tolerance, is a common pitfall in assessing immune tolerance, as noted by the International Society of Hematology 9