STAT3 and infection: For example, the infection of porcine epidemic diarrhea virus (PEDV) upregulates the expression of STAT3 and STAT5A in the porcine intestinal cells (IPEC-J2) (20), and genetic variants in the STAT3/STAT5A/STAT5B region are associated with inflammatory bowel disease (IBD), a complex gastrointestinal disease (21–23).