TLR4 and infection: Infection with Chlamydia in the female genital tract could drive increased expression of TLR2 and TLR4 accompanied by upregulation of cytokines, such as tumor necrosis factor α, interleukin 1α (IL-1α), and IL-6; these cytokines together trigger the inflammatory response during which tissue damage occurs (Agrawal et al., 2009).