In infectious diseases, the primary pathway utilized by the host to respond to the pathogen and clear the infection is typically MyD88-dependent TLR4 signaling, which is required for the host to defend against Gram-negative bacterial infections such as Klebsiella pneumoniae (K. pneumoniae)29 and Pseudomonas aeruginosa (P. aeruginosa).30 This evidence concerns the gene MYD88 and infectious disease.