IL18 and infection: Unlike infections with other intracellular bacteria, such as Legionella and Mycobacterium tuberculosis, inflammasome activation plays a deleterious role in the host response against Ehrlichia. This point is supported by several studies showing a strong link between the production of inflammasome-dependent cytokines, IL-18 and IL-1β, and the induction of pathogenic adaptive immune responses and liver damage.