IL21 and inflammatory bowel disease: IL-21 has been shown to be upregulated in the intestine from patients with IBD in several studies by different methods such as Western blotting of total protein extracts from tissue specimens, culture of lamina propria mononuclear cells (LPMCs) followed by ELISA on supernatants, intracellular flow cytometry on LPMCs [22, 55, 56], and immunohistochemistry of mucosal biopsies [57].