Although some TB granulomas are paucibacillary, these cells typically surround a community of Mycobacterium tuberculosis. TB is marked by the presence of pulmonary and extrapulmonary granulomas that are populated by macrophages, macrophage derivatives, and a panoply of other immune cells.

The most widely studied granulomas have been those that develop in tuberculosis (TB) and other persistent mycobacterial infections ( Cadena et al., 2017 Davis and Ramakrishnan, 2009 Pagan and Ramakrishnan, 2014).

These structures are common, and are seen in schistosomiasis ( Takaki et al., 2021), after the inhalation of silica and metals ( Leung et al., 2012), in atherosclerosis ( Johnson and Newby, 2009), and following the deposition of foreign bodies ( Molina-Ruiz and Requena, 2015) or insoluble proteins or lipids ( Terziroli Beretta-Piccoli et al., 2018).

Granulomas are compact, organized collections of mononuclear phagocytes-primarily macrophages ( Adams, 1976)-that develop in response to an unresolved infectious or foreign body stimulus ( Anderson et al., 2008 Pagan and Ramakrishnan, 2018 Williams and Williams, 1983).

State of survival plasma cores