CYBB and polyarticular arthritis: Mutations of genes determining NADPH oxidase 2 (NOX2) complex, a membrane enzyme complex in endothelial and phagocytic cells with primary function of generating ROS in response to innate immune stimuli, lead to chronic granulomatous disease (CGD), which is accompanied by various autoimmune manifestations, including inflammatory bowel disease, lupus, antiphospholipid syndrome, and polyarthritis (5).