NFKB1 and Arthritis: This disparity in response was observed in vitro and in vivo on the synthesis signal of pro-inflammatory cytokines (mediated by NF-κB and MAPK kinase activation) especially on the formation of immature pro-IL-1β as well as secretion of mature IL-1β, the central cytokine driving the microcrystal-induced arthritis (Figure 9).