Systemic Lupus Erythematosus

Indications for Testing

Multisystem disease presentation

Criteria for Diagnosis (American College of Rheumatology, 1997)

Diagnosis requires ≥4 of the following criteria to be present, serially or simultaneously, during any interval of observation
- Malar rash
- Discoid rash
- Photosensitivity
- Oral ulcers
- Arthritis (nonerosive)
- Pleuritis or pericarditis
- Renal disorder (persistent proteinuria or cellular casts)]
- Hematologic disorder (hemolytic anemia, leukopenia, lymphopenia, or recurrent thrombocytopenia)
- Immunologic disorder
- Antinuclear antibody (ANA) positive

Laboratory Testing

Initial testing – not disease-specific but may be helpful in determining organ involvement
- CBC – anemia, thrombocytopenia, leukopenia
- Urinalysis – hematuria; indicates renal disease
- Liver transaminases – may be elevated
- BUN/creatinine – may be elevated; indicates renal disease
- ANCA – rule out vasculitis
- Complement 3 and 4 (C3, C4) – elevated levels may be predictive for glomerulonephritis in SLE
- ESR/CRP – high elevations unusual in SLE
ANA test – useful as initial screen for SLE although not disease-specific; positive samples should be further tested to identify antibodies specific for SLE
- dsDNA >1:10 detected by immunofluorescence assay (IFA) – 50-60% of SLE
  - Presence of high antibody titers to native dsDNA is specific and diagnostic for SLE
- High avidity dsDNA – more sensitive for lupus nephritis than intermediate or low affinity anti-dsDNA antibodies
- Extractable nuclear antigens
  - Smith (Sm) antibodies – highly specific for SLE but occur in only 30-35% of cases
  - Ribonucleic protein (RNP) antibodies – not specific for SLE
  - SSA and SSB antibodies – not specific for SLE
- Histone and ssDNA antibodies – not specific for SLE
- Anti-ribonuclear P (anti-P) – associated with neurolupus
- Chromatin antibodies
  - Mainly used to diagnosis drug-induced lupus
  - 50-90% of SLE patients have these antibodies
  - Linked to proteinuria, glomerulonephritis, and disease activity
  - May be found in Sj ö gren syndrome and APS
Biomarkers of lupus nephritis
- Anti-C1q antibodies – high negative predictive value if absent; correlates with renal activity and flares, but no better than anti-dsDNA and complement
Consider the following testing to rule out other diseases
- Antiphospholipid antibodies (lupus anticoagulant, anticardiolipin and anti-beta-2 glycoprotein 1IgG and IgM assays)
- Cryoglobulin
Neurolupus
- CSF for cells, glucose, oligoclonal bands, culture
  - Cell count – mild elevations with mononuclear cells
  - Glucose – usually normal, but may be decreased in myelopathy
  - Oligoclonal bands
  - Interleukin 6, 8, 10 (if available) – very high, decreased with remission
Other testing
- EEG – frequently abnormal

Imaging Studies

MRI/CT of brain and/or spine
MR angiography – if vascular involvement considered

Differential Diagnosis

Other autoimmune diseases
- Mixed connective tissue disease
- Sjögren syndrome
- Dermatomyositis
Fibromyalgia
Vasculitis
Sarcoidosis
Infection
- Endocarditis
- M. tuberculosis
Glomerulonephritis
Malignancy
Drug-induced lupus
Hematologic/minocycline diseases
- Idiopathic thrombocytopenic purpura
- Thrombotic thrombocytopenic purpura
APS

EULAR 2010 recommendations
- Re-evaluation of previously negative antiphospholipid antibodies prior to pregnancy, surgery, transplant, or use of estrogen-replacement therapy in the presence of new neurologic event
  - Anti-Ro and anti-La antibodies prior to pregnancy
  - Anti-dsDNA, C3, C4 to support remission
- Other nonspecific testing every 6-12 months
  - CBC, ESR, CRP, albumin, CR or EGFR, UA and urine protein level
- Other monitoring based on toxicities of prescribed therapies
- Evaluation of cardiac risk factors
- Osteoporosis evaluation
- Cancer screening – follow society-specific recommendations for screening and surveillance

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the presence of several autoantibodies, formation of immune complexes, and inflammation in different organs.

Epidemiology

Incidence – 1/2,000 in the U.S. (1/2,500 in northern Europeans; 2/1,000 in African Americans)
Age – peak onset is 15-40 years
Sex – M<F 1:12 (ages 15-45); 1:2 other age groups
Ethnicity – greater incidence in African Americans, Asian Americans, and Hispanics than in Caucasians (3:1)

Risk Factors

Genetics – possible association with deletion of long arm of chromosome 1
Sun exposure
Drugs – hydralazine, procainamide, quinidine, penicillamine, acebutolol, and methyldopa
Epstein-Barr virus infection
Occupational exposure
- Crystalline silica
- Pesticides
- Mercury

Pathophysiology

Pathophysiology of SLE is not completely understood; however, the following have been implicated
- Apoptosis (programmed cell death) leading to loss of immune tolerance
- Interferon-alpha (IFN-α) and plasmacytoid dendritic cells (PDCs)
- Toll-like receptors through the induction of IFN-α by PDCs
Multiple pathogenic antibodies have been discovered
- Double-stranded DNA (dsDNA)
- Ro (anti-SSA)
- Smith (Sm)
- Antiphospholipid antibodies (anticardiolipin and beta-2 glycoprotein I)
- Lupus anticoagulant
- C1q
- Nucleosome
- La (anti-SSB)

Clinical Presentation

Dermatologic – malar discoid rash, photosensitivity, skin eruptions, alopecia
Musculoskeletal – arthritis, arthralgia, myalgia
Serositis – pleuritis, pericarditis
Renal – nephritis
Neurologic
- Central nervous system – meningitis, demyelinating disease, seizures, psychosis, mood disorder, stroke, chorea, myelopathy, headache, transient ischemic attack
- Peripheral nervous system – autonomic disorder, mononeuropathy, myasthenia gravis, cranial neuropathy, plexopathy, polyneuropathy
Hematologic – hemolytic anemia, leukopenia, thrombocytopenia, antiphospholipid syndrome symptoms
Cardiovascular – vasculitis, Libman-Sachs endocarditis
Ocular – sicca syndrome
Complications
- Osteoporosis – probably a combination of disease inflammation and steroids used in treatment
- Malignancy
  - Increased risk of hematologic cancer and non-Hodgkin lymphoma
  - Hepatobiliary cancers increased in men
  - Early coronary heart disease
- Adverse pregnancy outcomes
  - Higher risk of miscarriage
  - Higher rate of low birth weight infants

Treatment

Immunosuppressives are currently the mainstay of therapy
Newer biologics hold promise

Tests generally appear in the order most useful for common clinical situations

Test name: Anti-Nuclear Antibodies (ANA), IgG by ELISA with Reflex to ANA, IgG by IFA

ARUP #: 0050080

Methodology: Qualitative Enzyme-Linked Immunosorbent Assay (ELISA)/Semi-Quantitative Indirect Fluorescent Antibody (IFA)

Use:

First line test for connective tissue disease screening

All ELISA results reported as Detected are further tested by IFA

ANA ELISA screen is designed to detect antibodies against dsDNA, histone, SS-A (Ro), SS-B (La), Smith, snRNP/Sm, Scl-70, Jo-1, centromere, and an extract of lysed HEp-2 cells

Limitations:

Low titer ANAs common with advancing age; certain drugs may also cause low titer ANAs

ANA ELISA assays have been reported to have lower sensitivities for antibodies associated with nucleolar and specked ANA-IFA patterns

Follow-up:

Recommend cutaneous direct immunofluorescence testing of active edge of new lesion (lesional biopsy) if dermatologic manifestations are present

Test name: Connective Tissue Diseases Profile

ARUP #: 0051668

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Use:

Aid in identifying the specific connective tissue disease

Panel includes ribosomal P protein, centromere antibodies and the following IgG antibodies: Smith, RNP (U1), scleroderma (Scl-70), SSA (Ro), SSB (La), Jo-1

Test name: High Avidity Double-Stranded DNA (HA dsDNA) Antibody, IgG

ARUP #: 2005526

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Use:

Order as secondary screen based on results of ANA testing

More highly associated with renal involvement than intermediate- or low-affinity anti-dsDNA antibodies

dsDNA antibodies are screened using an ELISA assay

Test name: Double-Stranded DNA (dsDNA) Antibody, IgG by ELISA with Reflex to dsDNA Antibody, IgG by IFA

ARUP #: 0050215

Methodology: Qualitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody

Use:

Order as secondary screen based on results of ANA testing

dsDNA antibodies are screened using an ELISA assay

If dsDNA antibodies are detected, then dsDNA antibody IgG by IFA (using Crithidia luciliae) will be performed

Test name: Chromatin Antibody, IgG

ARUP #: 2005287

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Use:

Aid in diagnosis of drug-induced lupus

Test name: CBC with Platelet Count & Automated Differential

ARUP #: 0040003

Methodology: Automated Cell Count with Flow Cell Differential

Use:

Initial testing

Test name: Urinalysis, Complete

ARUP #: 0020350

Methodology: Reflective Photometry/Microscopic by Yellow IRIS

Use:

Identify renal disease

Test name: Bilirubin, Direct & Total, Serum or Plasma

ARUP #: 0020426

Methodology: Quantitative Spectrophotometry

Use:

Elevated levels indicate renal disease

Test name: Urea Nitrogen, Serum or Plasma

ARUP #: 0020023

Methodology: Quantitative Spectrophotometry

Use:

Evaluated levels indicate renal disease

Test name: Creatinine, Serum or Plasma

ARUP #: 0020025

Methodology: Quantitative Enzymatic

Use:

Evaluated levels indicate renal disease

Test name: Anti-Neutrophil Cytoplasmic Antibody with Reflex to Titer and MPO/PR-3 Antibodies

ARUP #: 2002068

Methodology: Semi-Quantitative Indirect Fluorescent Antibody/Semi-Quantitative Multi-Analyte Fluorescent Detection

Use:

Rule out vasculitis

If screen is positive, titer and MPO/PR-3 antibodies testing will be added to aid in antibody determination

Test name: Complement Component 3

ARUP #: 0050150

Methodology: Quantitative Immunoturbidimetric

Use:

Elevated levels may be predictive for glomerulonephritis in SLE

Test name: Complement Component 4

ARUP #: 0050155

Methodology: Quantitative Immunoturbidimetric

Use:

Elevated levels may be predictive for glomerulonephritis in SLE

Test name: Sedimentation Rate, Westergren (ESR)

ARUP #: 0040325

Methodology: Westergren

Use:

Not usually elevated

Test name: C-Reactive Protein

ARUP #: 0050180

Methodology: Quantitative Immunoturbidimetric

Use:

Not usually elevated

Additional Tests Available

Test name: Smith (ENA) Antibody, IgG

ARUP #: 0050085

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Order as secondary screen based on results of ANA

Test name: Lupus Comprehensive Reflexive Panel

ARUP #: 0050119

Methodology: Refer to individual components

Comments:

Test name: Anti-Nuclear Antibody (ANA), IgG by ELISA with Reflexes to ANA by IFA and to dsDNA, RNP, Smith, SSA, and SSB Antibodies

ARUP #: 0050317

Methodology: Qualitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody/Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Recommend if high suspicion of SLE or Sjögren syndrome

If ELISA screen is positive, then IFA using HEp-2 substrate will be added; if confirmed by IFA, titer and pattern will be reported and testing for dsDNA antibody and ENA antibodies will be added

Test name: RNP (U1) (Ribonucleic Protein) (ENA) Antibody, IgG

ARUP #: 0050470

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Helpful in detecting central nervous system SLE (somewhat rare)

Test name: Scleroderma (Scl-70) (ENA) Antibody, IgG

ARUP #: 0050599

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Extractable Nuclear Antigen Antibodies (RNP, Smith, SSA, & SSB)

ARUP #: 0050652

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Extractable Nuclear Antigen Antibodies (RNP, Smith, Scleroderma, SSA, & SSB)

ARUP #: 0050653

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Clarify pattern result from ANA

May help differentiate SLE from mixed connective tissue disease, rheumatoid arthritis, scleroderma, Sjögren syndrome

Test name: SSA (Ro) (ENA) Antibody, IgG

ARUP #: 0050691

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Order as secondary screen based on results of ANA testing

Test name: SSB (La) (ENA) Antibody, IgG

ARUP #: 0050692

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Order as secondary screen based on results of ANA testing

Test name: Centromere Antibody, IgG

ARUP #: 0050714

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Extractable Nuclear Antigen Antibodies (SSA & SSB)

ARUP #: 0050791

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Histone Antibody, IgG

ARUP #: 0050860

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Comments:

Test name: Neutrophil-Associated Antibodies

ARUP #: 0055506

Methodology: Qualitative Flow Cytometry

Comments:

Test name: Ribosomal P Protein Antibody

ARUP #: 0099249

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Helps in detecting central nervous system SLE (somewhat rare)

Test name: ssDNA Antibody, IgG

ARUP #: 0099528

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Comments:

Order as secondary screen based on results of ANA testing

Test name: Jo-1 Antibody, IgG

ARUP #: 0099592

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Helps in detecting inflammatory myopathies

Test name: C1q Binding Assay

ARUP #: 0050301

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Comments:

Test name: Antiphospholipid Syndrome Reflexive Panel

ARUP #: 2003222

Methodology: Clotting/Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Comments:

Test name: Cryoglobulin, Qualitative with Reflex to IFE Typing and Quantitative IgA, IgG, and IgM

ARUP #: 2002403

Methodology: Qualitative Cold Precipitation/ Qualitative IFE/Quantitative Nephelometry

Comments:

If qualitative is positive, Immunofixation Electrophoresis Typing and Quantitative IgA, IgG and IgM will be added

Test name: Cell Count, CSF

ARUP #: 0095018

Methodology: Cell Count/Differential

Comments:

Test name: Glucose, Plasma or Serum

ARUP #: 0020024

Methodology: Quantitative Enzymatic

Comments:

Test name: Albumin, Serum or Plasma by Spectrophotometry

ARUP #: 0020030

Methodology: Quantitative Spectrophotometry

Comments:

Test name: Interleukin 6 by MAFD

ARUP #: 0051537

Methodology: Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Interleukin 8 by MAFD

ARUP #: 0051538

Methodology: Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Interleukin 10 by MAFD

ARUP #: 0051534

Methodology: Quantitative Multi-Analyte Fluorescent Detection

Comments:

Guidelines

General

ARUP Institute for Clinical and Experimental Pathology®

Comprehensive Review: December 2011
Last Update: December 2011

Acute Phase Proteins

Antiphospholipid Syndrome

Connective Tissue Diseases

Cryoglobulinemia

Inflammatory Myopathies

Microscopic Polyangiitis

Mixed Connective Tissue Disease

Sarcoidosis

Scleroderma

Sjögren Syndrome

Thiopurine Methyltransferase Activity

Thrombotic Microangiopathies

Vasculitis

Wegener Granulomatosis