The discoveries that its synthesis is highly induced during macrophage activation [4] and that immune response gene 1 (Irg1, since then renamed aconitate decarboxylase) encodes the enzyme cis-aconate decarboxylase (ACOD1 in humans, CAD in other organisms), which converts cis-aconitate to itaconate [5, 6], have triggered intense efforts to elucidate functions of the endogenous ACOD1/itaconate axis in inflammation and infection. The gene discussed is ACOD1; the disease is infection.