- Several reports have indicated a relationship between reactivation of latent tuberculosis infection (LTBI) and treatment with tumor necrosis factor alpha (TNF) blocking agents. These biologic drugs have demonstrated high efficacy in the treatment of chronic inflammatory diseases. Several guidelines have been published worldwide suggesting pretreatment screening strategies for latent tuberculosis in candidates for TNF-blocking treatment, as well as a regimen for prophylactic therapy if latent tuberculosis is indeed diagnosed. There are considerable variations among the different guidelines. This review summarizes currently available data on the risk of infection and particularly, the increased risk profile for tuberculosis in patients treated with TNF-blocking agents. The role of TNF alpha blockers in the pathogenesis of tuberculosis and the existing protocols that have been formulated in order to minimize the risk of tuberculosis reactivation during TNF blockade are also outlined.