Antisynthetase syndrome is a chronic autoimmune disease that affects the muscles and is characterized by antibodies directed against an aminoacyl transfer RNA synthetase. Signs and symptoms can vary but may include myositis, polyarthritis, interstitial lung disease, thickening and cracking of the hands, and Raynaud phenomenon.
PATHOPHYSIOLOGY
The cause of antisynthetase syndrome seems to be linked to the production of aminoacyl-tRNA synthetases (ARS) autoantibodies. These autoantibodies appear after certain viral infections, drug exposure or in some people who already have a genetic predisposition. The exact role of autoantibodies in causing antisynthetase syndrome is not yet understood.
The most common ARS autoantibody associated with antisynthetase syndrome is anti-Jo1 (anti-histidyl). Other autoantibodies that may be involved include: anti-EJ (anti-glycyl), anti-OJ (anti-isoleucyl), anti-PL7 (anti-threonyl), anti-PL12 (anti-alanyl), anti-SC (anti-lysil), anti-KS (anti-asparaginyl), anti-JS (anti-glutaminyl), anti-Ha or anti-YRS (anti-threonyl), anti-tryptophanyl, and anti-Zo (anti-phenylalanyl).
SIGNS AND SYMPTOMS
Common symptoms of antisynthetase syndrome include:
- Fever
- Loss of appetite
- Weight loss
- Myositis
- Polyarthritis
- Interstitial lung disease causing shortness of breath, coughing, and/or dysphagia
- Thickened skin of tips and margins of the fingers
- Raynaud phenomenon
DIAGNOSIS
Diagnosis is considered in patients with an antisynthetase antibody plus two major criteria or one major criterion and two minor criteria:
Major criteria:
- Interstitial lung disease (not explained by environmental, occupational, medication exposure, and not related to any other base disease)
- Polymyositis or dermatomyositis
Minor criteria:
- Arthritis
- Raynaud phenomenon
- Mechanic’s hand
Additional testing can then be ordered to confirm the diagnosis, determine the severity of the condition, and assist with determining treatment. This testing varies based on the signs and symptoms present in each person, but may include:
- Blood tests to evaluate levels of muscle enzymes such as creatine kinase and aldolase
- Laboratory tests to look for the presence of autoantibodies associated with antisynthetase syndrome
- High resolution computed tomography (HRCT) of the lungs
- Electromyography (EMG)
- Muscle biopsy
- Pulmonary function testing
- Magnetic resonance imaging (MRI) of affected muscles
- Evaluation of swallowing difficulties and aspiration risk
- Lung biopsy
MANAGEMENT STRATEGIES & TREATMENT
Diagnosis is considered in patients with an antisynthetase antibody plus two major criteria or one major criterion and two minor criteria:
Major criteria:
- Interstitial lung disease (not explained by environmental, occupational, medication exposure, and not related to any other base disease)
- Polymyositis or dermatomyositis
Minor criteria:
- Arthritis
- Raynaud phenomenon
- Mechanic’s hand
Additional testing can then be ordered to confirm the diagnosis, determine the severity of the condition, and assist with determining treatment. This testing varies based on the signs and symptoms present in each person, but may include:
- Blood tests to evaluate levels of muscle enzymes such as creatine kinase and aldolase
- Laboratory tests to look for the presence of autoantibodies associated with antisynthetase syndrome
- High resolution computed tomography (HRCT) of the lungs
- Electromyography (EMG)
- Muscle biopsy
- Pulmonary function testing
- Magnetic resonance imaging (MRI) of affected muscles
- Evaluation of swallowing difficulties and aspiration risk
- Lung biopsy
CLINICAL TRIAL
For a full list of clinical trials relating to antisynthetase syndrome, click here.
RESOURCES
To learn more about antisynthetase syndrome and other autoimmune/auto-inflammatory disorders visit https://checkrare.com/diseases/autoimmune-auto-inflammatory-disorders/