IL4 and infection: We did not identify appreciable concentrations of IL-4 or IL-5 by using ELISA in RSV-infected mice compared with mock-infected mice during the first 10 days after RSV infection, with only IL-4 concentrations being statistically significant but just slightly greater than the limit of detection at day 6 after infection (see Fig E2, A and B, in this article's Online Repository at www.jacionline.org).