Differential Expression of IL-36 Family Members and IL-38 by Immune and Nonimmune Cells in Patients with Active Inflammatory Bowel Disease

IL-1 family includes IL-38 (IL-1F10) and the subfamily of IL-36 and is the central mediators of inflammatory diseases, including pustular psoriasis, atopic dermatitis, rheumatoid arthritis, and gut inflammation. The purpose of the study was to evaluate on tissue of the patients with inflammatory bowel disease (IBD), the IL-36α, IL-36β, IL-36γ, IL-36Ra, and IL-38 gene and cell expression and its correlation with clinical activity. Patients and Methods. A cross-sectional and comparative study was performed. Seventy patients with IBD and 30 noninflamed non-IBD controls were enrolled. Gene expression was measured by RT-PCR. Protein expression was detected by double-staining immunohistochemistry. Results. The mRNA expression of IL-36 family members but not IL-38 was increased in colonic mucosa from patients with active ulcerative colitis versus Crohn's disease group and noninflammatory control group (P<0.05). However, only gene expression of IL-38 was increased in tissue from patients with inactive ulcerative colitis versus active disease and control group (P<0.005). Conversely, gene expression of IL-36Ra was significantly higher in colonic tissue from patients with active versus inactive ulcerative colitis and noninflamed control group (P<0.05). A differential protein overexpression of IL-36α, IL-36β, IL-36γ, IL-36Ra, and IL-38 by intestinal epithelial cells, macrophages, CD8+ T cells, and/or versus dendritic cells (pDCs) was found in patients with active inflammatory bowel disease compared with noninflamed controls. Conclusion. IL-38 and IL-36 family members' expression was increased by immune and nonimmune cells in patients with active inflammatory bowel disease. These cytokines and IL-36Ra might represent novel therapeutic targets in patients with gut inflammation.