TNF and viral infectious disease: Since exacerbation was frequently observed in asthmatic patients after viral infection, we suspect that a cytokine storm, including inflammatory cytokines (interleukin [IL]-6 and tumour necrosis factor [TNF]-α), anti-inflammatory cytokines (IL-10), anti-viral cytokines (interferon [IFN]-γ), and helper T (Th) 2 cytokines (IL-4 and IL-13), may occur in the lung following A(H1N1)pdm09 infection.