Myositis Profile (11 Antigens) Test
Myositis Profile (11 Antigens) Test
Myositis is a group of autoimmune muscle disorders characterized by chronic muscle inflammation and weakness. The Myositis Profile (11 Antigens) Test is a specialized panel used to detect autoantibodies associated with different types of idiopathic inflammatory myopathies (IIMs), such as polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM), and necrotizing myopathy.
Myositis can be associated with systemic autoimmune diseases, malignancies, and interstitial lung disease (ILD). Early detection of specific myositis-related antibodies helps in diagnosing, classifying, and guiding treatment for these disorders.
What is the Myositis Profile (11 Antigens) Test Used For?
This test is used to:
- Identify specific autoantibodies linked to different types of myositis.
- Differentiate between various inflammatory myopathies.
- Assist in diagnosing associated conditions, such as interstitial lung disease and autoimmune overlap syndromes.
Guide treatment decisions based on antibody patterns.
Antigens Included in the Myositis Profile
The test detects autoantibodies against the following 11 antigens
Jo-1 (Histidyl-tRNA Synthetase)
-
Associated with anti-synthetase syndrome and interstitial lung disease.
PL-7 (Threonyl-tRNA Synthetase)
-
Seen in anti-synthetase syndrome.
PL-12 (Alanyl-tRNA Synthetase)
-
Linked to interstitial lung disease.
EJ (Glycyl-tRNA Synthetase)
-
Present in anti-synthetase syndrome.
OJ (Isoleucyl-tRNA Synthetase)
-
Associated with muscle and lung involvement.
Mi-2 (Nuclear Helicase)
-
Found in dermatomyositis.
SRP (Signal Recognition Particle)
-
Seen in necrotizing autoimmune myopathy.
MDA5 (Melanoma Differentiation-Associated Protein 5)
-
Associated with clinically amyopathic dermatomyositis and rapidly progressive interstitial lung disease.
TIF1-γ (Transcription Intermediary Factor 1-γ)
-
Linked to dermatomyositis and cancer-associated myositis.
NXP-2 (Nuclear Matrix Protein 2)
-
Found in juvenile and adult dermatomyositis.
SAE1 (Small Ubiquitin-like Modifier Activating Enzyme 1)
-
Associated with dermatomyositis.
Symptoms of Myositis
Symptoms vary depending on the type of myositis but commonly include:
- Progressive muscle weakness (especially in shoulders, hips, and thighs)
- Muscle pain and tenderness
- Fatigue and difficulty swallowing (dysphagia)
- Skin rashes (in dermatomyositis)
- Shortness of breath (if interstitial lung disease is present)
Who Should Get Tested?
The Myositis Profile (11 Antigens) Test is recommended for individuals who:
- Have symptoms of myositis, such as muscle weakness, fatigue, joint pain, or skin rashes.
- Are suspected of having autoimmune muscle diseases, including polymyositis, dermatomyositis, or inclusion body myositis.
- Have interstitial lung disease (ILD) with suspected autoimmune involvement, as myositis-related antibodies can affect lung function.
- Experience unexplained muscle pain, weakness, or inflammation that persists despite normal routine tests.
Are being monitored for disease progression or treatment response in diagnosed cases of myositis.
Preparation for the Test
No special preparation is required. A blood sample is drawn from a vein. Inform your doctor about any current medications or autoimmune conditions.
Interpretation of Results
|
Antibody |
Result |
Associated Condition |
Clinical Significance |
|
Anti-Jo-1 (Histidyl-tRNA Synthetase) |
Positive |
Polymyositis, Dermatomyositis, Antisynthetase Syndrome (ASS) |
Common in myositis; associated with ILD, arthritis, Raynaud’s phenomenon. |
|
Anti-PL-7 (Threonyl-tRNA Synthetase) |
Positive |
Antisynthetase Syndrome (ASS), Myositis-ILD |
Strongly linked to progressive ILD. |
|
Anti-PL-12 (Alanyl-tRNA Synthetase) |
Positive |
Antisynthetase Syndrome (ASS), Myositis-ILD |
Severe lung involvement, arthritis, fever. |
|
Anti-EJ (Glycyl-tRNA Synthetase) |
Positive |
Antisynthetase Syndrome (ASS), Myositis-ILD |
Associated with lung fibrosis and muscle weakness. |
|
Anti-OJ (Isoleucyl-tRNA Synthetase) |
Positive |
Antisynthetase Syndrome (ASS), Myositis-ILD |
Severe muscle and lung involvement. |
|
Anti-Mi-2 (Nuclear Helicase) |
Positive |
Dermatomyositis (DM) |
Strong association with heliotrope rash, Gottron’s papules, good response to therapy. |
|
Anti-SRP (Signal Recognition Particle) |
Positive |
Necrotizing Autoimmune Myopathy (NAM) |
Associated with severe, rapidly progressing muscle weakness, poor response to steroids. |
|
Anti-MDA5 (Melanoma Differentiation-Associated Protein 5) |
Positive |
Amyopathic Dermatomyositis (ADM), Rapidly Progressive ILD |
High risk of lung fibrosis, severe respiratory failure, poor prognosis. |
|
Anti-TIF1-γ (Transcription Intermediary Factor 1-γ) |
Positive |
Cancer-Associated Dermatomyositis (CADM) |
Strong malignancy risk; requires cancer screening. |
|
Anti-NXP-2 (Nuclear Matrix Protein 2) |
Positive |
Juvenile Dermatomyositis, Cancer-Associated Myositis |
Severe muscle weakness, calcinosis in children, malignancy risk in adults. |
|
Anti-SAE1 (Small Ubiquitin-like Modifier Activating Enzyme 1) |
Positive |
Dermatomyositis with Severe Skin Involvement |
Linked to rash before muscle symptoms, dysphagia. |
FAQs
Can myositis be cured?
There is no permanent cure, but early diagnosis and immunosuppressive therapy can help manage symptoms.
How is myositis treated?
Treatment may include corticosteroids, immunosuppressants, and physical therapy.
Does myositis affect the lungs?
Yes, some forms (e.g., anti-synthetase syndrome, MDA5-positive myositis) can cause interstitial lung disease (ILD).
Who should get tested?
Individuals with unexplained muscle weakness, skin rashes, or respiratory symptoms linked to autoimmune diseases.
How long does it take to get results?
Results are usually available within 7-10 days.
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