Myositis Profile-IgG (16 Antigens) Test
Myositis Profile-IgG (16 Antigens) Test
Myositis is a group of autoimmune muscle disorders characterized by chronic muscle inflammation and weakness. The Myositis Profile-IgG (16 Antigens) Test is a specialized panel used to detect autoantibodies associated with various idiopathic inflammatory myopathies (IIMs), including polymyositis (PM), dermatomyositis (DM), necrotizing myopathy, inclusion body myositis (IBM), and overlap syndromes.
Autoantibodies against specific muscle and nuclear antigens are critical for diagnosis, classification, and prognosis of myositis-related diseases. This test is also useful in identifying lung involvement, malignancies, and associated autoimmune disorders.
What is the Myositis Profile-IgG (16 Antigens) Test Used For?
This test is used to:
- Identify specific autoantibodies linked to various types of myositis.
- Distinguish between different inflammatory myopathies.
- Assess risk for interstitial lung disease (ILD) and cancer-associated myositis.
- Guide treatment decisions based on antibody profiles.
Antigens Included in the Myositis Profile-IgG (16 Antigens) Test
This test detects autoantibodies against 16 myositis-related antigens, including
Jo-1 (Histidyl-tRNA Synthetase)
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Associated with anti-synthetase syndrome and interstitial lung disease.
PL-7 (Threonyl-tRNA Synthetase)
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Seen in anti-synthetase syndrome.
PL-12 (Alanyl-tRNA Synthetase)
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Linked to interstitial lung disease.
EJ (Glycyl-tRNA Synthetase)
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Present in anti-synthetase syndrome.
OJ (Isoleucyl-tRNA Synthetase)
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Associated with muscle and lung involvement.
Mi-2 (Nuclear Helicase)
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Found in dermatomyositis.
SRP (Signal Recognition Particle)
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Seen in necrotizing autoimmune myopathy.
MDA5 (Melanoma Differentiation-Associated Protein 5)
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Linked to clinically amyopathic dermatomyositis and rapidly progressive ILD.
TIF1-γ (Transcription Intermediary Factor 1-γ)
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Associated with dermatomyositis and cancer-associated myositis.
NXP-2 (Nuclear Matrix Protein 2)
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Found in juvenile and adult dermatomyositis.
SAE1 (Small Ubiquitin-like Modifier Activating Enzyme 1)
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Associated with dermatomyositis.
Ku (Nuclear Antigen)
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Seen in overlap syndromes.
PM-Scl100 (Polymyositis-Scleroderma Complex Antigen 100)
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Found in polymyositis and scleroderma overlap.
PM-Scl75 (Polymyositis-Scleroderma Complex Antigen 75)
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Associated with scleromyositis.
Ro-52 (Tripartite Motif-Containing Protein 21/TRIM21)
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Present in connective tissue diseases and myositis.
cN1A (Cytosolic 5’-Nucleotidase 1A)
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Linked to inclusion body myositis (IBM).
Who Should Get Tested?
The Myositis Profile-IgG (16 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.
Symptoms of Myositis
Common symptoms 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)
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
- Positive for specific antibodies: Suggests an autoimmune myopathy subtype.
- Negative results: Do not rule out myositis; further clinical correlation is needed.
- Presence of multiple antibodies: May indicate overlapping autoimmune syndromes.
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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