Immunological tolerance induction (ITI)

Immunological tolerance induction is a physiological process and therapeutic strategy designed to render the immune system non-responsive to specific antigens that would otherwise elicit a harmful response. Naturally, this occurs through central tolerance in primary lymphoid organs and peripheral tolerance in the circulation, preventing the immune system from attacking self-tissues. Clinically, induction of tolerance is a primary goal in managing autoimmune diseases, preventing organ transplant rejection, and treating hypersensitivity reactions such as allergies. It is also a critical protocol in hemophilia treatment to eliminate neutralizing antibodies (inhibitors) against replacement clotting factors. Unlike general immunosuppression, successful tolerance induction results in long-term, antigen-specific quiescence, ideally allowing the patient to remain immunocompetent against pathogens while ignoring the specific target antigen.

Other names

Immune tolerance inductionAntigen-specific tolerancePeripheral tolerance inductionCentral tolerance inductionDesensitizationImmune unresponsiveness

Induction of immunological tolerance involves the repetitive administration of antigens or the use of immunomodulatory agents to promote clonal deletion, anergy of effector lymphocytes, or the expansion of FOXP3+ regulatory T cells (Tregs) and regulatory B cells (Bregs). This process shifts the immune profile from a pro-inflammatory state to an anti-inflammatory state, often mediated by cytokines such as IL-10 and TGF-beta.