Incidentally, asthma is characterized by increased Th2 cytokine production; however, in this model, Th2 cytokines, including IL-4, IL-5, and IL-13, which were upregulated in the HDM group, were not further upregulated in the HDM/RSV group at the mRNA (Figure 1G) and protein (Figure 1H) level. This evidence concerns the gene IL4 and asthma.