Anti-PM/Scl autoantibodies in patients without clinical polymyositis or scleroderma.

OBJECTIVE

To characterize patients with anti-PM/Scl but no definite myositis-scleroderma (PM/SSc) overlap or either polymyositis/dermatomyositis (PM/DM) or systemic sclerosis (SSc) alone.

METHODS

Review of all patients with anti-PM/Scl identified at a reference serologic clinical laboratory.

RESULTS

We identified 5 patients with anti-PM/Scl not considered to have either PM, SSc, or PM/SSc. One had primary Sjögren's syndrome but the other 4 had some feature(s) of illness consistent with PM/DM or SSc, such as hypertensive crisis or interstitial lung disease. These 5 patients represented 10% of the total number of patients with anti-PM/Scl identified in our clinical laboratory.

CONCLUSION

Anti-PM/Scl may be a marker for atypical or subclinical presentations of the usually associated disease, or this autoantibody may precede expression of the underlying disease. The antibody may also be present in patients who never express PM, SSc, or PM/SSc. Anti-PM/Scl without the usually described illnesses is not uncommon in our series of 55 patients with anti-PM/Scl.