IL1B and chronic kidney disease: Surprisingly, protein levels of pro–IL-1β, mature IL-1β (Figure 1, J–L), and pro–IL-18 (Figure 1, M and N) were similar for NC and CKD groups; but protein levels of mature IL-18 trended toward increased expression in the CKD group (P = 0.051 vs. NC, Figure 1, M and O).