ADGRE1 and arthritic joint disease: In line with the temporal appearance of the osteoproliferative lesions, we also detected notably increased Irg1 expression and itaconate levels in the inflamed paws during the later course of arthritis (figure 4D, E), which was also paralleled by increased expression of the myeloid marker genes Itgam and Emr1 (online supplemental figure S4a).