Systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a diverse auto-immune rheumatic disease principally affecting women during childbearing years. The female-to-male ratio is about 9:1. Although virtually all patients have skin and joint disease, between 30 and 50% will also develop renal, lung, heart and central nervous system involvement. SLE has a prevalence of approximately 20–200 per 100,000, occurring most commonly in the Afro-Caribbean population. Its diversity of clinical features is, apparently, matched by the wide range of associated autoantibodies. Antibodies to double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), nucleosomes, C1q, Ro and RNP are found most commonly. Autoantibodies to dsDNA and nucleosomes are useful diagnostically and probably contribute to the pathogenesis of the disease. Its pathogenesis is a complex combination of hormonal, genetic and trigger factors (infection, ultraviolet radiation). The prognosis has improved in the past 50 years from 50% 4-year survival to around 85% 10-year survival. This improvement has been brought about in part by optimizing the use of hydroxychloroquine, corticosteroids and immunosuppressives (azathioprine, cyclophosphamide and more recently mycophenolate). With an increased knowledge of the factors involved in pathogenesis, some exciting new modes of treatment (e.g. B cell depletion, anti-B cell stimulating factors) are entering clinical trials with the hope of further improving mortality and morbidity.