Moreover, because the XO gene expression is markedly upregulated by pro-inflammatory cytokines (e.g., IL-1β) [51], the higher inflammation observed in NDD-CKD patients could also mediate a higher expression of XO, explaining the increased XO activity and the positive correlation observed between XO activity and inflammatory markers (IL-1β and CRP levels) in these patients. The gene discussed is CRP; the disease is chronic kidney disease.