IL1R1 and rheumatoid arthritis: In addition to being essential for TLR4-mediated IL-12p40 production by bmMs [29], MyD88 is required for LPS-induction of IL-1β as well as for the NF-κB-mediated induction of NLRP3 and IL-1β by TLRs important in CIA/RA, such as TLR2 [30–32] and IL-1R [33,34] that do not couple via the TRIF, MyD88-independent pathway [35]: thus, we investigated whether 12b-mediated inhibition of IL-1β production was also associated with downregulation of MyD88 signalling.