Interferon Gamma Release Assays for Latent Tuberculosis Infection

Abstract Tuberculosis (TB) is a major global infectious cause of death and an enormous public health challenge. TB causes a wide spectrum of disease in humans that ranges from asymptomatic infection to symptomatic disease, which creates difficulty in TB control efforts. Control of the infection relies on multiple components of the immune system, including activation of lung macrophages, which play a key role in the innate response by phagocytosis and sequestration of M. tuberculosis bacilli within the phagosome. M. tuberculosis has evolved numerous strategies to evade elimination by the host response. States of immunosuppression such as HIV coinfection, antitumor necrosis factor drug regimens, or older age during latent infection are all risk factors for progression to active disease.