This malar (or butterfly) rash over the face of a young girl is a typical rash seen with SLE (or DLE). The rashes are made worse by sun exposure. Click on image for link to original webpage

Background: Systemic lupus erythematosus (SLE) is an autoimmune disease involving multiple organ systems that is defined clinically and associated with antibodies directed against cell nuclei. Its multisystem manifestations and attendant complications from use of immunosuppressive agents make the diagnosis and management of this entity challenging. Pathophysiology: Autoantibodies, circulating immune complexes, and T lymphocytes all contribute to the expression of disease. Organ systems affected include dermatologic, renal, central nervous system (CNS), hematologic, musculoskeletal, cardiovascular, pulmonary, the vascular endothelium, and gastrointestinal. The revised criteria for SLE must include 4 of the following: Malar rash Discoid rash Photosensitivity Oral ulcers Arthritis Serositis Renal disorder Neurologic disorder Hematologic disorder Immunologic disorder Antinuclear antibody Extract from eMedicine click on this link to see complete webpage.

LABORATORY FINDINGS

Immunologic Abnormalities
 

• *Presence of antinuclear antibodies (98%)
• *Presence of anti-DNA antibodies (double stranded or native) - highly specific for SLE;  found in most patients with active renal disease (90%) and in patients with active disease but without renal involvement (50%); titres reflect disease activity;  these do not occur in drug-induced LE.
• *Antibodies against extractable nuclear antigens.  These antigens include nuclear ribonuclear protein (nRNP) and nuclear nonnucleic acid glycoprotein (Smith {Sm} antigen).  The latter appears to be highly specific for patients with SLE;  present in 25% - 30% of patients with SLE
• *Positive test for LE cells (70% - 85%) specific for SLE but not as sensitive as the presence of antinuclear antibodies;  LE cells may be seen in synovial, pleural, and pericardial fluid
• *Presence of circulating immune complexes - indicates active disease.
• Decreased serum complement (75%) - reflects consumption by immune complexes and implies active disease
• Increased serum y-globulins (80%) - reflects increased immunologic activity
• Presence of rheumatoid factor (20% - 35%) - reflects increased immunoglobulins
• False-positive nontreponemal test for syphilis (15% - 20%) - reflects increased immunoglobulins

• Mild normocytic anaemia (50% - 80%) - usually chronic disease type;  occasionally there is an autoimmune haemolytic anaemia with a positive direct Coombs' test
• Moderate leukopenia - autoimmune mechanism
• Lymphocytopenia - due to lymphocytotoxic antibodies;  this is the most frequent initial laboratory finding
• Thrombocytopenia - autoimmune mechanism;  often reflects disease activity
• Increased fibrin split products - seen in lupus nephritis

• Decreased serum albumin (50%-60%) - reflects chronic disease or loss of albumin in urine in the nephrotic form of lupus nephritis
• Increased sedimentation rate and C-reactive protein - usually reflects disease activity

• Haematuria, cellular casts, and proteinuria reflect active lupus nephritis.

• Low white blood cell (WBC) count (<3000/ul); predominant lymphocytes LE cells and antinuclear antibodies
• Decreased complement

• Findings of aseptic meningitis

• Immunogluorescent studies show deposits of immunoglobulins and complement.