Introduction
infections, tuberculosis
INFECTIONS, TUBERCULOSIS
Trained immunity is an emerging concept which describes epigenetic, metabolic and functional reprogramming of innate immune cells that leads to an enhanced heterologous immune response to infections. Trained innate immune cells are characterized by an increased host defense function upon restimulation (higher cytokine production capacity, phagocytosis, intracellular pathogen killing). Bacillus Calmette-Guérin (BCG) is the vaccine against tuberculosis and has been shown to induce trained immunity and protect against heterologous infections (Recently, de Bree et al. have observed that the circadian rhythm may influence BCG-induced trained immunity (The protective effects of trained immunity and BCG have been shown against a variety of viral pathogens (