Connective Tissue Diseases

Indications for Testing

Appropriate clinical presentation, including arthralgias or arthritis

Laboratory Testing

Nonspecific testing – CBC, erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP)
Initial screen is ANA EIA; if musculoskeletal complaints are present, consider rheumatoid testing (rheumatoid factor, synovial fluid)
- If screen is positive, then proceed with ANA IFA
- Titer level has no bearing on diagnosis or disease severity once it is above established normal level
Further testing based on ANA IFA
- Anti-U1-RNP
  - High titers are associated with SSc/SLE/polymyositis overlap syndromes
- Urinalysis – rule out glomerulonephritis
- ANCA – rule out vasculitis
- For further testing strategies, consult the following
  - Systemic lupus erythematosus
  - Sjögren syndrome
  - Rheumatoid arthritis (RA)
  - Mixed connective tissue disease
  - Scleroderma (systemic sclerosis)
  - Inflammatory myopathies
  - Connective Tissue Disease Testing algorithm

Autoimmune connective tissue diseases and major autoantibodies

Autoimmune Connective Tissue Diseases and Major Autoantibodies
Systemic lupus erythematosus	dsDNA, smith, cardiolipin, lupus anticoagulant, histone (drug-induced lupus)
Rheumatoid arthritis	RF IgM, cyclic citrullinated peptide (CCP)/citrullinated protein antibodies
Scleroderma/systemic sclerosis	Scl-70, centromere, RNA polymerase I/III
Sjögren syndrome	Ro (SSA), La (SSB)
Mixed connective tissue disease	RNP
Polymyositis/Dermatomyositis	Jo-1, Mi

Differential Diagnosis

Arthritis
- RA
- Osteoarthritis
- Crystalline arthritis
- Reactive arthritis (Campylobacter spp, Salmonella, Shigella, group A streptococcus)
- Ankylosing spondylitis
- Psoriatic arthritis
- Sarcoidosis
Myositis
- Demyelinating disease (multiple sclerosis, etc)
- Peripheral neuropathy
- Paraneoplastic syndromes
- Guillain-Barré syndrome
- Cushing syndrome
Systemic presentation
- Drug-related autoimmune presentation
- Antiphospholipid syndrome
- Vasculitis
- Malignancy
  - B-cell lymphoma
  - T/NK-cell lymphoma
  - Thymoma
- Endocarditis
Renal
- Acute glomerulonephritis
- Vasculitis
Central nervous system
- Vasculitis
- Stroke
- Migraine
- Infectious meningitis/encephalitis
- Brain tumor
- Malignancy
  - Lymphoma
  - Leukemia (most commonly ALL)
Hematologic
- Autoimmune hemolytic diseases
- Malignancy
  - Infiltrative metastatic
  - Leukemia (ALL and AML)
  - Myeloproliferative neoplasms
  - Myelodysplastic syndromes

Once diagnosis is made, use monitoring tests based on organ involvement
- Urinalysis is reasonable screen for renal disease
- If cytopenias present, follow with sequential CBCs
- Certain treatment drugs require liver function testing

Several autoimmune connective tissue diseases may present with similar features. These diseases include systemic lupus erythematosus, Sjögren syndrome, mixed connective tissue disease, scleroderma (systemic sclerosis), progressive systemic sclerosis, inflammatory myopathies (polymyositis/dermatomyositis [PM/DM]) and undifferentiated connective tissue disease.

Epidemiology

Incidence – ranges from 15-50/100,000 depending on disease
Age – onset is 15-40 years; peak onset in 20s
Sex – M<F, 1:6-10

Pathophysiology

Circulating antigen-antibody complexes affect a variety of organs
Multisystem disease presentation; major blood vessels are the predominant target

Clinical Presentation

Constitutional – fever, anorexia, weight loss
Musculoskeletal – arthralgias, arthritis, synovitis, myopathy
Dermatologic – skin rashes, Raynaud phenomenon, photosensitivity
Cardiopulmonary – pleuritis, pericarditis, fibrosis, chest pain
Renal – proteinuria, glomerulonephritis
Otorhinolaryngologic – sicca syndrome, oral ulcers
Gastrointestinal – gastroesophageal reflux disease
Neurologic – seizures, encephalopathy
Hematologic – cytopenias (involving neutrophils, erythrocytes and platelets)

Treatment

Anti-inflammatory therapies – glucocorticosteroids and other drugs such as methotrexate and mycophenolate

Clinical Background

Epidemiology

Incidence – varies by disease but lower than in adults
Sex – M<F for most disorders
Age – presents more often >10 years

Clinical Presentation

Constitutional – fever, anorexia, weight loss (most common)
Musculoskeletal – arthralgias, arthritis, synovitis, myopathy, weakness
Dermatologic – skin rash, Raynaud syndrome, photosensitivity
Cardiopulmonary – chest pain, pericarditis, pleuritis
Gastrointestinal – abdomen pain, diarrhea, hepatitis

Diagnosis

Indications for Testing

Appropriate clinical presentation

Laboratory Testing

Nonspecific testing – CBC, erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP)
Initial screen is ANA EIA; if musculoskeletal complaints are present, consider testing for rheumatoid factor IgM antibodies to rule out juvenile idiopathic arthritis
- If screen is positive, proceed with ANA IFA
- Titer level has no bearing on diagnosis or disease severity once it is above established normal level
If ANA EIA is negative and suspicion for connective tissue disease is high, consider testing for ANA by IFA or specific autoantibodies based on clinical suspicion
- Scleroderma – ANA IFA has good predictive value but several autoantibodies are associated with the nucleolar pattern
- Polymyositis/dermatomyositis – follow up with myositis profile
- Sjögren syndrome – follow up with SSA and/or SSB
For further testing strategies, consult the following
- Systemic lupus erythematosus
- Sjögren syndrome
- Mixed connective tissue disease
- Scleroderma
- Idiopathic inflammatory myopathies
- Connective Tissue Disease Testing algorithm

Differential Diagnosis

Polyarthritis
- Juvenile rheumatoid arthritis
- Juvenile ankylosing spondylitis
- Infectious arthritis
- Psoriatic arthritis
- Vasculitis
- Growing pains
- Reactive arthritis (Campylobacter spp, Salmonella, Shigella, group A streptococcus)
Renal
- Acute glomerulonephritis
- Vasculitis
Central nervous system
- Vasculitis
- Migraine
- Brain tumor
Rash
- Kawasaki disease
- Scarlet fever
- Parvovirus
Systemic presentation
- Vasculitis
- Malignancy
- Endocarditis
- Acute rheumatic fever
- Sarcoidosis
Myositis/weakness
- Muscular dystrophies
- Guillain-Barré syndrome
- Cushing disease
- Mitochondrial diseases
- Metabolic disease
- Infections
  - Toxoplasma gondii
  - Enterovirus (polio)
  - Trichinella spiralis (trichinosis)
Hematologic
- Autoimmune hemolytic diseases
- Malignancy
  - Infiltrative metastatic
  - Leukemia
  - Myeloproliferative neoplasms
  - Myelodysplastic syndromes

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

Test name: CBC with Platelet Count & Automated Differential

ARUP #: 0040003

Methodology: Automated Cell Count with Flow Cell Differential

Use:

Non-specific test to initially evaluate connective tissue disease

If cytopenias present, use sequentially for monitoring

Test name: Sedimentation Rate, Westergren (ESR)

ARUP #: 0040325

Methodology: Westergren

Use:

Non-specific test to initially evaluate connective tissue disease

Test name: C-Reactive Protein

ARUP #: 0050180

Methodology: Quantitative Immunoturbidimetric

Use:

Non-specific test to initially evaluate connective tissue disease

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:

Initial screen for connective tissue diseases

All ELISA results reported as "Detected" are further evaluated 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:

Results are not disease specific

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

Test name: Connective Tissue Diseases Profile

ARUP #: 0051668

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Use:

Follow-up test based on positive ANA

Components include Smith (ENA) antibody; RNP (U1) (ribonucleic protein); SSA (Ro); SSB (La); Jo-1; ribosomal P protein; centromere; scleroderma (Scl-70)

Test name: Rheumatoid Arthritis Panel

ARUP #: 2003277

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

Use:

Rule out RA

Test name: Cyclic Citrullinated Peptide (CCP) Antibody, IgG

ARUP #: 0055256

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Use:

May help diagnose RA or evaluate likely development of RA in patients with undifferentiated arthritis

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: Urinalysis, Complete

ARUP #: 0020350

Methodology: Reflective Photometry/Microscopic by Yellow IRIS

Use:

Screen for renal disease

Test name: Hepatic Function Panel

ARUP #: 0020416

Methodology: Refer to individual components.

Use:

Monitor drug treatment

Additional Tests Available

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

ARUP #: 0050470

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Secondary screen based on ANA test

High titers associated with SSc/SLE/polymyositis overlap syndromes

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

ARUP #: 0050653

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

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:

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

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

ARUP #: 0050652

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Jo-1 Antibody, IgG

ARUP #: 0099592

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

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

ARUP #: 0050691

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: PM/Scl-100 Antibody, IgG, by Immunoblot with Reflex to ANA IFA

ARUP #: 2003040

Methodology: Semi-Quantitative Immunoblot/Semi-Quantitative Immunofluorescence Antibody

Comments:

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

ARUP #: 0050692

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

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

Comments:

dsDNA antibodies are screened using an ELISA assay

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

Test name: Smith (ENA) Antibody, IgG

ARUP #: 0050085

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Ribosomal P Protein Antibody

ARUP #: 0099249

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: ssDNA Antibody, IgG

ARUP #: 0099528

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

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: Lupus Comprehensive Reflexive Panel

ARUP #: 0050119

Methodology: Refer to individual components

Comments:

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

ARUP #: 0050599

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Centromere Antibody, IgG

ARUP #: 0050714

Methodology: Semi-Quantitative Multi-Analyte Fluorescent Detection

Comments:

Test name: Uric Acid, Body Fluid

ARUP #: 0020513

Methodology: Quantitative Spectrophotometry

Comments:

Guidelines

General

Tebo, Anne E., PhD. Assistant Medical Director, Immunology at ARUP Laboratories; Assistant Professor of Pathology (Clinical), University of Utah

Comprehensive Review: July 2011
Last Update: February 2012

Cryoglobulinemia

Inflammatory Myopathies

Mixed Connective Tissue Disease

Systemic Lupus Erythematosus

Thiopurine Methyltransferase Activity