In fact, patients with IBD are more exposed to nephrotoxicity due to the risk of dehydration, which can activate the renin–angiotensin–aldosterone system involved in glomerular ischemia and interstitial fibrosis, and due to the systemic inflammation characterized by the production of IL-23 and TNF-α, which could contribute to the exacerbation of tubulointerstitial lesions in IgAN. Here, TNF is linked to inflammatory bowel disease.