STAT3 and hydrops fetalis: The mRNA expressions of 10 immune genes (IRF3, TLR3, CCR4, MAPK3, TYK2, STAT3, STAT4, STAT6, CCR8, and GATA3) were upregulated in HF steers, whereas a pro-inflammatory cytokine, IL-2, was upregulated in LF steers (Table 3).