Although we cannot definitively show that pups that deceased at day 1 or pups that were viable at day 1 and deceased at day 2 had higher circulating levels of IL-27, the trends in IL-27 gene expression, serum levels, and mortality suggest the possibility that IL-27 levels are maintained at lower concentrations in neonatal animals most likely to survive the infection (Fig. 1 and 4A). This evidence concerns the gene IL27 and infection.