More targeted analysis, via stratification of children based on asthma or prior bronchiolitis in infancy, also reveals indistinguishable responses in virus-stimulated cytokine production between individuals with the homozygous TLR4 haplotype (Asp/Asp+Thr/Thr) or the heterozygous haplotype (Asp/Gly+Thr/Ile) (Figures 5 and 6). Here, TLR4 is linked to asthma.