Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans), the pathogen of aggressive periodontitis, upregulates IL-1β expression in human mononuclear leucocytes45 and macrophages.46 Leukotoxin, an important virulence factor that targets leucocytes, rapidly activates caspase-1 and thus induces a massive secretion of IL-1β in human monocytes and macrophages.47,48 The NLRP345,49 and AIM2 inflammasomes,50 reactive oxygen species and cathepsin B51 might be involved in the process. The gene discussed is IL1B; the disease is periodontitis.