IL1B and rheumatoid arthritis: To determine whether myeloid IPMK contributes to Fc receptor signaling, which is a major effector of immune responses in rheumatoid arthritis, bone-marrow-derived macrophages (BMDMs) isolated from IpmkΔLysM and IpmkWT littermates were treated with a heat-aggregated gamma globulin (HAGG) immune complex, after which the mRNA levels of pro-inflammatory cytokines such as Tnf-α, Il-1β, and Il-6 were analyzed.