Antisynthetase Syndrome
Antisynthetase syndrome is a rare autoimmune disease that has been classified as a subgroup of inflammatory myopathic disorders. A characteristic feature of antisynthetase syndrome is presence of an autoantibody to one of the aminoacyl–transfer RNA (tRNA) synthetases, which are intracellular enzymes that attach amino acids to tRNA during protein synthesis. Of the 10 identified antiaminoacyl-tRNA synthetases, the syndrome has been most often associated with autoantibodies to 3 of them: anti–Jo-1 antibody (60% of cases), anti–PL-12 (17%), and anti–PL-7 (12%).
Antisynthetase syndrome has been associated with HLA haplotype DRB1*0301 and with exposures to tobacco, cleaning chemicals, mold, bird droppings, and airborne particles from the September 11, 2001, World Trade Center attack.
The classic triad of antisynthetase syndrome consists of interstitial lung disease (ILD), myositis, and nonerosive arthritis. Although this triad eventually develops in up to 90% of patients with antisynthetase syndrome, approximately 25% present only with symptoms of arthritis, 25% present with myositis, and 15% to 30% present with ILD. Other conditions associated with antisynthetase syndrome include Raynaud phenomenon, gastroesophageal reflux disease, fever, and fissured eruptions on the hands (“mechanic hands”).
ILD affects approximately 70% to 95% of patients with antisynthetase syndrome and is the most common cause of morbidity and mortality. The incidence of ILD and pulmonary hypertension is higher in patients with anti–PL-7 and anti–PL-12 antibodies. Overall survival for patients with anti–Jo-1 antibody has been 70% at 10 years vs 47% for patients with non–anti–Jo-1 synthetase antibodies.
Diagnosis of antisynthetase syndrome requires identification of an autoantibody to aminoacyl-tRNA synthetase. Antisynthetase antibody profiles are available at LabCorp. Antibodies are detected by an enzyme-linked immunoassay. Reference range is <20 units.
The preferred specimen is 3 mL of serum, collected in a red top tube or SST tube.
References
Ghias A et al. Patient with Pulmonary Symptoms, Dysphagia, and Raynaud Disease, JAMA 2023;330:658-59.
Lundberg IE , Tjärnlund A , Bottai M , et al; International Myositis Classification Criteria Project Consortium, Euromyositis Register, and Juvenile Dermatomyositis Cohort Biomarker Study and Repository (JDRG) (UK and Ireland). 2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups. Ann Rheum Dis. 2017;76(12):1955-1964.
Marco JL , Collins BF. Clinical manifestations and treatment of antisynthetase syndrome. Best Pract Res Clin Rheumatol. 2020;34(4):101503.
Zhao N , Jiang W , Wu H, et al. Clinical features, prognostic factors, and survival of patients with antisynthetase syndrome and interstitial lung disease. Front Immunol. Published online August 10, 2022. doi:10.3389/fimmu.2022.872615
Huang K , Aggarwal R. Antisynthetase syndrome: a distinct disease spectrum. J Scleroderma Relat Disord. 2020;5(3):178-191. doi:10.1177/2397198320902667
