TNFSF13B and irritable bowel syndrome: Moreover, it has been demonstrated that an altered systemic immune response is active in IBS patients, with the release of pro-inflammatory cytokines like B-cell activating factor (BAFF), Interleukin 1B (IL-1B), Tumor necrosis factor alpha (TNF-a), Interleukin 6 (IL-6) and Interleukin 8 (IL-8) [8–12].