Since both intestinal mucosa and PBMC lnc-ITSN1-2 closely correlated with risk, severity, and inflammation response of IBD, and since CD4+ T cell activation, proliferation as well as differentiation were key bioprocesses of IBD development and progression, we hypothesized that lnc-ITSN1-2 might regulate IBD CD4+ T cell activation, proliferation, and differentiation, and we thus carried out the following in vitro experiments. The gene discussed is CD4; the disease is inflammatory bowel disease.