It is interesting to note that the P. aeruginosa penta-acylated LPS binds TLR2 and is predominantly found in isolates from non-CF and early CF disease (30), whereas the hexa- and hepta-acylated forms that prevail in well-established P. aeruginosa infections, with higher acylation pattern been associated with higher CF disease severity in late stages, efficiently bind and activate the human TLR4-MD2-CD14 complex, inducing a more robust inflammatory response (31–34). Here, TLR4 is linked to cystic fibrosis.