To and colleagues found higher plasma levels of proinflammatory cytokines and chemokine in the group of patients with acute respiratory distress syndrome (ARDS) caused by viral A(H1N1) influenza, throughout the initial 10 days after symptom onset [8] . Bermejo-Martin and colleagues found that mediators involved in the development of Th17 cells (IL-6, IL-8, IL-9, IL-17), Th1 cells (TNFα, IL-15, IL-12p70) and type II interferon (IFNγ) had high systemic levels in hospitalized patients with nvA(H1N1) influenza [9] . The detrimental or beneficial role of these cytokines in severe illness is not known.