Thus, the TLR4 Asp299Gly + Thr399Ile heterozygous haplotype has no detectable effect on the capacity of randomly selected 7–9 year old children to mount either RSV-stimulated or LPS-driven responses regardless of whether the children exhibited a clinical phenotype of current asthma or those with a history of infantile bronchiolitis. Here, TLR4 is linked to asthma.