Our previous study had even found elevated mRNA and protein expressions of IL12p40 both in PB and intestinal mucosa of UC patients.20 In this study, we comprehensively evaluated the expression of IL12p40 and its receptor IL12RB1 systematically and locally in both UC and CD patients and identified an upregulation of IL12p40 in IBD patients, indicating an important role of IL12p40 in IBD pathogenesis. This evidence concerns the gene IL12RB1 and Cowden disease.