myositis-specific antibodies
Autoantibodies specifically associated with inflammatory myopathies in children.
Full Definition
Myositis-specific antibodies (MSAs) are a group of autoantibodies that are specifically found in patients with inflammatory myopathies and are rarely present in other autoimmune conditions or healthy individuals. In pediatric rheumatology, these antibodies help classify different subtypes of juvenile inflammatory myopathies and can provide prognostic information about disease course and complications. Common MSAs include anti-Jo-1, anti-Mi-2, anti-MDA5, and anti-TIF1γ antibodies. Different antibody profiles are associated with distinct clinical phenotypes, such as increased risk of interstitial lung disease, skin manifestations, or malignancy risk. Testing for MSAs is crucial for proper classification and management of juvenile dermatomyositis and related conditions.
Usage
Usage note: Distinguish from myositis-associated antibodies (MAAs) which are less specific.
In Context
- "The presence of anti-MDA5 antibodies indicated increased risk for rapidly progressive interstitial lung disease." — Laboratory interpretation
- "Myositis-specific antibodies were negative, but the clinical presentation remained consistent with juvenile dermatomyositis." — Clinical correlation