systemic lupus erythematosus (SLE)

Last edited 10/2023 and last reviewed 11/2023

Systemic lupus erythematosus is the classic prototype of a chronic, multisystem, inflammatory connective tissue disorder of autoimmune origin (1,2).

  • often follows a relapsing and remitting pattern (3)
  • the disease is characterised by the presence of a wide spectrum of autoantibodies (2)
    • 98% of SLE patients have antinuclear antibodies (ANA) but are non-specific
    • anti-double-stranded DNA (dsDNA) seen in around 70% of cases is highly specific for SLE
    • other autoantibodies present in SLE patients include - anti-Smith, anti-ribosomal P and anti-proliferating cell nuclear antigen (PCNA) (3)
  • it is non-organ specific and characterised by vasculitis
  • due to its broad clinical presentation the disease may vary from rash and arthritis through anaemia and thrombocytopenia to serositis, nephritis, seizures, and psychosis (4)

  • SLE, as a chronic inflammatory disorder, is thought to be driven by autoantibodies that target multiple organ systems including joints, skin, and kidneys
    • SLE is characterized by pathogenic autoantibodies that target specific tissues, however many additional cell types (for example B cells, T cells) and cytokines (for example type I interferon (IFN-I)-a) are involved in the inflammatory response (5)
    • dysregulation of both adaptive and innate immunity plays a role in the pathogenesis of SLE
      • adaptive immunity and SLE
        • B cells play a central role in the pathogenesis of SLE, mainly by producing autoantibodies but also by producing cytokines and by presenting antigens to T cells
        • SLE can occur secondary to defective proteins that regulate T cells in the dysfunctional clearance of immune cells
          • thus part of the pathology of SLE may be due to loss of the immune tolerance and the persistence of attractive B- and T-cell populations
      • inate immunity and SLE
        • dysregulation of the innate immune system also contributes to SLE
        • immune complexes of autoantibodies with endogenous RNA and DNA can be taken up by plasmacytoid dendritic cells
          • leads to activation of toll-like receptor (TLR)7 and TLR9, respectively, and generates IFN-I
            • IFN-I can lead to further augmentation of adaptive immunity by enhancing the antigen-presenting function of monocytes and dendritic cells and activating B cells
Clinical variants of lupus erythematosus

Some of the clinical variants of lupus erythematous include the following (6):

  • systemic lupus erythematosus (SLE)
  • cutaneous lupus erythematosus (CLE) (including subacute cutaneous lupus erythematosus (SCLE) and discoid lupus erythematosus (DLE))
  • child-onset lupus erythematosus
  • neonatal lupus erythematosus
  • drug-induced lupus erythematosus (DILE)

Management principles (7):

  • mild disease characterized as constitutional symptoms, mild rash or arthritis, and thrombocytopenia with a platelet count no less than 50,000/mm3
    • is recommended to be treated with the addition of glucocorticoids
  • moderate disease activity, characterized as rheumatoid-like arthritis, more severe skin disease or cutaneous vasculitis affecting <18% of body surface area, serositis, or thrombocytopenia with a platelet count no less than 20,000/mm3
    • is recommended to be treated with the addition of immunosuppressives to antimalarials and glucocorticoids (options include methotrexate, azathioprine, mycophenolate, or calcineurin inhibitors, with the addition of belimumab in refractory cases)
  • severe disease activity, categorized as major organ threatening disease such as kidney and central nervous system disease
    • is recommended to be treated with the addition of mycophenolate, cyclophosphamide, or rituximab

Reference:

Related pages:

epidemiology

pathogenesis

clinical features

investigations

diagnosis

differential diagnosis

management

prognosis

co-morbidities in SLE (systemic lupus erythematosus)