CRP and chronic kidney disease: Serum C-reactive protein (CRP) and proinflammatory cytokine levels - including tumor necrosis factor alpha and interleukins 1 and 6 - are increased in 30-50% of the patients with CKD.1,2,3 IL-6 increases serum levels of hepcidin, a liver-derived peptide hormone that inhibits the duodenal absorption of iron and the mobilization of iron in the reticuloendothelial system.2 High hepcidin levels lead to iron sequestration and hypoferremia.