Antisynthetase syndrome

Anti-synthetase syndrome is an autoimmune disease.

It is associated with interstitial lung disease, dermatomyositis, and polymyositis

==Signs and symptoms==Diagnostic criteria include: interstitial lung disease, inflammatory myopathy, and inflammatory polyarthritis affecting small joints symmetrically. Other supporting features may include fever, Raynaud's phenomenon and "mechanics hands"-thick, cracked skin usually on the palms and radial surfaces of the digits.

Pathogenesis

It is postulated that autoantibodies are formed against aminoacyl-tRNA synthetases. The synthethases 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.

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
• Anti-Jo-1 antibody testing
• Electromyography
• Muscle biopsy
• Pulmonary function testing
• Lung biopsy

Treatment

Unfortunately, treatment for the anti-synthetase syndrome is limited, and usually involves immunosuppressive drugs such as glucocorticoids. For patients with pulmonary involvement, the most serious complication of this syndrome is pulmonary fibrosis and subsequent pulmonary hypertension.

Additional treatment with azathioprine and/or methotrexate may be required in advanced cases.

Prognosis

Prognosis is largely determined by the extent of pulmonary damage.