Anti-synthetase syndrome is an autoimmune disease associated with

interstitial lung disease Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of respiratory diseases affecting the interstitium (the tissue and space around the alveoli (air sacs)) of the lungs. It concerns alveolar epithelium, pu ...

dermatomyositis Dermatomyositis (DM) is a long-term inflammatory disorder which affects skin and the muscles. Its symptoms are generally a skin rash and worsening muscle weakness over time. These may occur suddenly or develop over months. Other symptoms may inc ...

, and

polymyositis Polymyositis (PM) is a type of chronic inflammation of the muscles (inflammatory myopathy) related to dermatomyositis and inclusion body myositis. Its name means "inflammation of many muscles" ('' poly-'' + '' myos-'' + '' -itis''). The inflam ...

Signs and symptoms

As a

syndrome A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek language, Greek σύνδρομον, meaning "concurrence". When a sy ...

, this condition is poorly defined. Diagnostic criteria require one or more antisynthetase antibodies (which target tRNA synthetase enzymes), and one or more of the following three clinical features: interstitial lung disease, inflammatory myopathy, and inflammatory polyarthritis affecting small joints symmetrically. Other supporting features may include fever,

Raynaud's phenomenon Raynaud syndrome, also known as Raynaud's phenomenon, eponymously named after the physician Auguste Gabriel Maurice Raynaud, who first described it in his doctoral thesis in 1862, is a medical condition in which the spasm of small arteries cau ...

and "mechanics hands"-thick, cracked skin usually on the palms and radial surfaces of the digits. The disease, rare as it is, is more prevalent in women than in men. Early diagnosis is difficult, and milder cases may not be detected. Also, interstitial lung disease may be the only manifestation of the disease. Severe disease may develop over time, with intermittent relapses.

Pathogenesis

It is postulated that autoantibodies are formed against aminoacyl-tRNA synthetases. The synthetases may be involved in recruiting antigen-presenting and inflammatory cells to the site of muscle or lung injury. The specific molecular pathway of the process awaits elucidation.

Antisynthetase antibodies

The most common antibody is "Anti-Jo-1" named after John P, a patient with polymyositis and interstitial lung disease detected in 1980. This anti- histidyl tRNA Synthetase antibody is commonly seen in patients with pulmonary manifestations of the syndrome. The following are other possible antibodies that may be seen in association with antisynthetase syndrome: Anti-PL-7, Anti-PL-12, Anti-EJ, Anti-OJ, Anti-KS, Anti-Zo, Anti-Ha-YRS, and Anti-SRP.

Diagnosis

In the presence of suspicious symptoms a number of test are helpful in the diagnosis: * Muscle enzymes are often elevated, i.e.

creatine kinase Creatine kinase (CK), also known as creatine phosphokinase (CPK) or phosphocreatine kinase, is an enzyme () expressed by various tissues and cell types. CK catalyses the conversion of creatine and uses adenosine triphosphate (ATP) to create pho ...

* Anti-Jo-1 antibody testing * Electromyography *

Muscle biopsy In medicine, a muscle biopsy is a procedure in which a piece of muscle tissue is removed from an organism and examined microscopically. A muscle biopsy can lead to the discovery of problems with the nervous system, connective tissue, vascular s ...

Pulmonary function test Pulmonary function testing (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity ...

ing * Lung biopsy * Imaging such as High Resolution computed tomography ANTISYNTHETASE SYNDROME AND ITS ASSOCIATION WITH INTERSTITIAL LUNG DISEASE-A CLINICAL AND RADIOLOGICAL REVIEW Naresh Kumar,Bhavya Basetti, Rajoo Ramachandran, Prabhu Radhan,Venkata Sai P.M. http://ijomcr.net/radiology/ In certain situations, testing of other antibodies, specific imaging (MRI, thoracic high resolution computed tomography), and swallowing evaluation may be needed.

Treatment

Unfortunately, treatment for the anti-synthetase syndrome is limited, and usually involves immunosuppressive drugs such as

glucocorticoid Glucocorticoids (or, less commonly, glucocorticosteroids) are a class of corticosteroids, which are a class of steroid hormones. Glucocorticoids are corticosteroids that bind to the glucocorticoid receptor that is present in almost every verteb ...

s. For patients with pulmonary involvement, the most serious complication of this syndrome is

pulmonary fibrosis Pulmonary fibrosis is a condition in which the lungs become scarred over time. Symptoms include shortness of breath, a dry cough, feeling tired, weight loss, and nail clubbing. Complications may include pulmonary hypertension, respiratory failu ...

and subsequent pulmonary hypertension. Additional treatment with

azathioprine Azathioprine (AZA), sold under the brand name Imuran, among others, is an immunosuppressive medication. It is used in rheumatoid arthritis, granulomatosis with polyangiitis, Crohn's disease, ulcerative colitis, and systemic lupus erythematosus, ...

and/or methotrexate may be required in advanced cases.

Prognosis

Prognosis is largely determined by the extent of pulmonary damage.

References

External links

{{Medical resources , DiseasesDB = ddb34912 , ICD10 = M35.8 , ICD9 = , ICDO = , OMIM = , MedlinePlus = , eMedicineSubj = , eMedicineTopic = , MeshID = C537778 , Orphanet = 81 Rare syndromes Syndromes affecting muscles Rheumatology Autoimmune diseases Lung disorders Syndromes affecting the lung Syndromes affecting joints