Definition
SLE is a complex, systemic autoimmune disease with a variable course that can be associated with potentially life-threatening involvement of internal organs. The organ involvement in particular determines the prognosis and therefore also the treatment.
A solid diagnosis, early evaluation of any organ involvement and the need to assess disease activity require regular clinical and laboratory tests.
History, prevalence, etiology, pathogenesis
The first description of the skin symptoms was made by Biett in 1833, the name "lupus erythematosus" was coined by his pupil Cazenave in 1850, Hebra described and named the typical "butterfly erythema" in 1856. The Viennese dermatologist Moriz Kaposi first recognised lupus erythematosus as a systemic disease and described the main internal manifestations in 1869 and 1872.
In European studies, the prevalence of SLE is between 25 and 91/100,000, the ratio of women to men is 10:1 and the average age at onset of the disease is 29 years. In addition to gender, genetic factors, hormonal influences (oestrogen), ethnicity (more frequent and usually more severe in black people than in white people) and socio-economic status also play a role.
Hargrave's discovery of the LE cell in 1948 marked the beginning of the identification of the immunological characteristics of SLE. In addition to the anti-histone antibodies that trigger the LE cell phenomenon, they bind other chromatin structures such as double-stranded DNA (dsDNA), but also RNA-binding proteins (Sm, Ro, La, RA33) and cell surfaces (phospholipids, erythrocytes, thrombocytes).
Some of these autoantibodies are pathogenic, either directly or by forming immune complexes that are deposited in the tissue and are locally responsible for inflammation in various organs (kidneys, joints, skin, vascular system). Generally speaking, most organ manifestations are a consequence of (immune complex-mediated) inflammatory or vasculitic processes, a consequence of the clearance of antibody-laden cells, or a consequence of thrombotic/thrombo-embolic events in the context of an increased tendency to coagulate.
Key clinical manifestations
SLE is characterised by a variable combination of symptoms:
- General symptoms such as fever, severe tiredness and fatigue, swelling of the lymph nodes. General symptoms are found in almost all patients
- Typical infestation of the skin and serous membranes: pleura, pericardium, peritoneum; SLE pleuritis (30-60%) and pericarditis (11-54% in echocardiographic studies) are relatively common, SLE peritonitis is less common (11%)
- Blood count changes: low numbers of all cell series possible, both red and white blood cells and platelets (anaemia, leukopenia, lymphopenia, thrombocytopenia)
- Increased tendency to clot (thrombosis)
- very frequent musculoskeletal symptoms with pain and inflammation in joints and muscles (myalgia/arthralgia, or myositis and arthritis). These symptoms occur in up to 95% of patients and impair their quality of life
- Potentially life-threatening involvement of internal organs:
- Kidney (up to 50% of cases)
- Lungs (prevalence 4-9% for pneumonitis)
- Brain and nervous system (neurolupus)
- Heart and blood vessels (endocarditis up to 50%, myocarditis in 7-10%), atherosclerotic changes (usually with long duration of illness and poorly controllable chronic inflammatory reaction)
Diagnosis
The diversity of the clinical picture with different organ involvement and variable severity and different manifestations in the serum (keyword antibodies, blood count) often makes SLE a diagnostic challenge. The typical skin manifestations and laboratory findings (such as anti-nuclear antibodies [ANA] or anti-dsDNA antibodies) are typical of the disease and frequent, but can also be only moderately altered or completely absent.
The diagnosis is difficult to differentiate from infections or neurological or purely dermatological diseases. Even with a confirmed diagnosis, it is often not easy to distinguish SLE relapses from infections or side effects of therapy. A multidisciplinary approach is necessary in complex cases (rheumatology, nephrology, dermatology, neurology, and others).
Therapy
In the treatment of SLE, the clinic, in particular the organ involvement, plays a central role. Despite years of (successful) clinical use, the data situation for individual forms of therapy and organ systems sometimes needs to be expanded. The presentation here is deliberately kept very brief and clear because the individual course of the disease must be taken into account, especially in lupus.
The aim is immunomodulation or immunosuppression. In very mild cases or concomitantly, topical and symptomatic medications are used, such as topical glucocorticoids for skin infections, or non-steroidal anti-inflammatory drugs (NSAIDs) for musculoskeletal symptoms, provided there is no impairment of kidney function.
Systemic gluocorticoids, antimalarials (hydroxychloroquine), mycophenolate mofetil, azathioprine or methotrexate are used depending on the severity of the disease and after careful assessment of the individual benefit/risio profile.
In severe cases with acute organ involvement, the immunosuppressant cyclophosphamide is used; in refractory situations, the biologics belimumab and rituximab or experimental extracorporeal procedures such as immunoadsorption are used.
SLE is a complex, systemic disease that should be treated in (or in close cooperation with) a centre with experience in diagnosis and therapy, where an interdisciplinary approach is also possible.
Dr. Georg Stummvoll
Recommended books
- Aringer M, Hrsg. Aktuelle Therapieoptionen beim systemischen Lupus erythematodes. UniMed Verlag, 3. Auflage, Bremen, 2014 (übersichtlich, kurzgefasst).
- Wallace DJ, Hahn BH, Hrsg. Dubois Lupuss erythematosus and related conditions, Elsevier, Philadelphia, 8. Auflage, 2013 (Standardwerk in englischer Sprache)