After single infection with H3N2, an elevated mRNA expression of pro-inflammatory cytokines TNF and IFN-γ (mean fold change of 2.22 and 1.86, respectively), and anti-inflammatory cytokines IL-10 and TGF-β (mean fold change of 1.92 and 2.40 respectively), was observed (Figure 7). Here, TNF is linked to infection.