Elsevier

Medicine

Volume 38, Issue 2, February 2010, Pages 73-80
Medicine

SLE
Systemic lupus erythematosus

https://doi.org/10.1016/j.mpmed.2009.10.006Get rights and content

Abstract

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.

Section snippets

Epidemiology

SLE is found worldwide, with an estimated prevalence of 22–241/100,000 population. In the UK, the Caribbean and the USA, it is more common and more severe in females of African descent than in white Caucasians. In a study in Birmingham, UK, the estimated prevalence in adult women was 206/100,000 in Afro-Caribbeans, 95/100,000 in South 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 50 years. The

Aetiology

The precise aetiology of SLE is unknown. It is hypothesized that, like most systemic auto-immune conditions, SLE is triggered by one or a series of external stimuli in a genetically susceptible individual. The highly skewed sex differences and the age of onset in females point to a strong hormonal influence.

Pathogenesis

There is evidence that anti-double-stranded DNA (dsDNA) antibodies are directly pathogenic and related to disease activity. Circulating immune complexes are an immunopathological hallmark of SLE. They can deposit or be formed in the skin, kidney and brain, thereby initiating an inflammatory reaction, and clearance of these complexes may be impaired in SLE patients. Immune complexes also activate complement consumption. Certain complement fragments (e.g. C3a) cause the release of

Non-specific features

Patients can present with fever, fatigue, anorexia, weight loss and/or lymphadenopathy, and often need to undergo a series of investigations, including biopsy, to exclude malignancy or infection, such as tuberculosis. Fever is associated with active disease and must be differentiated from infection. SLE patients are immunosuppressed as a result of the disease and its treatment. C-reactive protein (CRP) is usually not raised in active SLE (except in serositis and arthritis). If CRP is found to

Autoantibodies

At least 100 autoantigens have been found to be targets in SLE, but few are clinically important. Antinuclear antibodies (ANA) are positive in more than 95% of patients. Raised anti-dsDNA antibody titres were found in 61% of patients in the authors' London cohort of 401 SLE patients. Anti-dsDNA antibodies are closely related to renal disease and an increase in titre should alert the clinician to a possible flare of disease, particularly if it is associated with decreasing C3 concentrations.

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Management

Treatment of SLE should be tailored to the manifestations of the individual's disease. All treatment plans should be discussed fully with the patient and adverse effects of drug therapies explained. Current therapies have significantly improved survival (85% 10-year survival). With improved prognosis, problems related to medication (e.g. diabetes mellitus, hypercholesterolaemia) and problems related to chronic organ damage (hypertension and end-stage renal failure) must be addressed. The aims

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