Immunopharmacology of Trained Immunity in Infectious and Non-Infectious Diseases: A Review

Trained immunity is a newly recognized facet of the innate immune system in which prior exposure to certain stimuli (such as vaccines, microbial components, or endogenous danger signals) induces long-lasting functional adaptations in innate immune cells. These adaptations are characterized by epigenetic and metabolic reprogramming, leading to enhanced responsiveness against subsequent challenges. Unlike adaptive immunity, trained immunity is non-specific, broad-spectrum, and involves monocytes, macrophages natural killer (NK) cells, and their progenitors. This review explores the immunopharmacological mechanisms that underlie trained immunity, examines how pharmacological manipulation of these pathways can influence host defense, and discusses implications in both infectious and non-infectious diseases. While induction of trained immunity can enhance protection against pathogens, inappropriate or excessive training may contribute to chronic inflammation and autoimmunity. Therapeutic strategies targeting trained immunity offer potential in vaccine development, infection control, cancer immunotherapy, and treatment of chronic inflammatory diseases.