Because PU.1 plays an essential role in the ontogenesis of a variety of immune cells (4–9) and various immune cell-associated tumors (3, 10, 11), researchers have begun to investigate the role of PU.1 in another large category of immune cell-related illnesses, systemic autoimmune diseases, which is a chronic and potentially life-threatening disease of the immune system that characterized by numerous autoantibodies and abnormal homeostasis of immune cells (12). The gene discussed is SPI1; the disease is immune system disorder.