Overall, st2−/− mice tended to have higher mediator levels in lungs than WT mice; especially 14 days after infection with influenza A modest but statistically significant differences were seen in pulmonary IL-6 (P<0.001), IL-1β (P<0.01), KC (P<0.05), IL-10 (P<0.05) and IL-33 (P<0.05) concentrations. This evidence concerns the gene IL33 and infection.