Systemic Lupus Erythematosus Health Article

Abstract

Systemic lupus erythematosus (SLE) is a diverse autoimmune rheumatic disease principally affecting women during childbearing years. The female-to-male ratio is around 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 40 to 200 per 100,000, occurring most commonly in Afro-Caribbean population. Its diversity of clinical features is, apparently, matched by the wide range of associated autoantibodies. Of the most commonly found are those to dsDNA, ssDNA, nucleosomes, C1q, Ro and RNP. 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, ultra-violet 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 plaquenil, 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 improving mortality and morbidity.

• Revision of classification of lupus nephritis and overall reduction in the use of cyclophosphamide in the treatment of renal lupus

• Biological treatments, many currently in Phase 3 studies may provide a more directed approach to therapy with less adverse unwanted side effects

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with protean clinical manifestations that may affect any organs or system. Table 1 shows the 1997 revised American College of Rheumatology (ACR) criteria for the classification of SLE. The disease is characterized by flares, remissions and autoantibodies directed against several intracellular and cell-surface antigens. The course of the disease is variable and regular review is essential to detect new and recurrent organ/system involvement. However, not all of the antibodies found in SLE are clinically relevant; Table 2 shows the prevalence of autoantibodies in 401 patients attending the University College Hospital/Middlesex Hospital Lupus Clinic between 1978 and 2004.

Patients with SLE are now living longer as a result of more appropriate use of ‘standard drugs’ such as prednisone, azathioprine and cyclophosphamide, and adjunctive therapies such as anti-hypertensives and cholesterol lowering drugs. Use of dialysis and renal transplantation has also improved survival, and new immunotherapies are under development. Management of a patient with SLE rigorously tests the clinician’s skills and judgement. Such patients are best cared for by experienced physicians with support from a multidisciplinary team.

Epidemiology

SLE is found worldwide, with an estimated prevalence of 12–64/100,000 population. In the UK, the Caribbean and the USA, it is more common and more severe in black females than in white Caucasians. In a study in Birmingham, UK, the estimated prevalence was 206/100,000 in Afro-Caribbeans, 95/100,000 in Asians and 36/100,000 in Europeans. The incidence is higher in urban populations. In most patients, SLE develops between the ages of 15 and 45 years. The female:male ratio is at least 9:1. In a minority of patients, disease develops after the age of 50 years, and in this subgroup the female:male ratio is 4:1. In childhood disease, the ratio of girls to boys is 3:1.