Another prospective study showed that early gut colonization with B. fragilis in high amounts at age 1 week and 1 month after birth is associated with suppressing TLR4 mRNA expression and LPS-induced IL-6 andC-C motif chemokine ligand (CCL4) at age 12 months [135], suggesting such bacterium may influence immune development and reduce the risk of asthma in later life. Here, TLR4 is linked to asthma.