Popa et al. and Matera et al. demonstrated that LPS from B. quintana resulted in the downregulation in human monocytes of nearly all cytokines normally produced by TLR4 in response to LPS [19, 20] and B. quintana's antagonism of TLR4 may be responsible for the absence of symptoms normally associated with bacteremia with Gram-negative organisms, such as septic shock. This evidence concerns the gene TLR4 and septic shock.