IL6 and viral infectious disease: The cytokines and chemokines expression profiles indicated that although the WSN virus replicated efficiently in mice lungs, the transcript levels of IL-4 and IL6 in the NS1 F9Y mutant virus infection group were about 6.7- and 3.5-fold higher than those in the WSN infection group at 3 dpi (p < 0.01, p < 0.05) (the control group were PBS-infected mice).