Systemic lupus erythematosus Systemic lupus erythematosus (SLE) typically affects women (circa 9:1 female:male ratio) in the 16-55 age group [Ballou et al. 1982]. It is commoner among patients of African/Afro-Caribbean, South Asian or Chinese/other Asian ethnic groups. It ranges from a mild to a lifethreatening or fatal disorder [Petri et al. 2012a]. Active disease is associated with raised anti-dsDNA antibodies and reduced levels of complement C3 and/or C4 levels. Current therapy is, in fact, very effective for most patients. In mild to moderate disease, hydroxychloroquine is now commonly used as steroid-sparing therapy for all patients. For patients with active disease, corticosteroids are at the heart of current therapy, often combined with steroid sparing agents such as azathioprine, methotrexate, leflunomide, ciclosporin or mycophenolate. In patients with severe or life-threatening renal, nervous system or pulmonary disease, oral or pulsed intravenous cyclophosphamide has been typically used over the past 20 years [Boumpas et al. 1992]. As a consequence, the survival rate for SLE has steadily increased. In a review of this topic [Urowitz et al. 2008] the authors point out that since the 1950s, SLE has changed from a disease with a 50% mortality at 5 years to one of over 90% 5-year survival. The challenge, in recent years, has been less about finding drugs with greater efficacy than corticosteroids and cyclophosphamide and more about developing drug regimes with lower toxicity. Corticosteroids, in particular, have been associated with higher rates of infection, cardiovascular and bone disease [Ruiz-Irastorza et al. 2012; Petri et al 2012b]. Cyclophosphamide is associated