After the first report of the successful use of low-dose IL-2 in a 36-year-old SLE patient as evidenced by the subsidence of arthritis and skin eruption as well as serological improvement and functional improvement of CD25++FoxP3+CD127lo Treg cells [60], a series of 5 patients with refractory SLE who received daily subcutaneous injections of 1.5 million IU of human IL-2 (aldesleukin) for five consecutive days were found to have selective expansion of Treg number despite the absence of formal clinical assessment of SLE disease activity [61]. The gene discussed is FOXP3; the disease is systemic lupus erythematosus.