Outcome of anti-PL12 positive patients with antisynthetase syndrome.

Objectives: The aim of the present study was to assess the outcome in anti-PL12 patients with antisynthetase syndrome (ASS).

Methods: The medical records of anti-PL12 (n=5) patients with ASS were retrospectively analyzed without prior selection. To exclude false-positive patients, we included patients who were successively tested positive for anti-PL12 antibody at least twice by immunodot and/or Western blot.

Results: Anti-PL12 patients experienced: myositis (n=2), Raynaud's phenomenon (n=2), mechanic's hands (n=1), joint impairment (n=4), digestive involvement (n=2), and interstitial lung disease (ILD) (n=4). The two patients with myositis exhibited deterioration of muscle manifestations despite therapy. As regards outcome of ILD, patients developed resolution (n=1), stabilization (n=1) or deterioration (n=2) of pulmonary status. One patient died of pyogenic pneumonia.

Conclusion: Our series underscores that the presence of anti-PL12 antibody is associated with a particular phenotype of ASS characterized by: (1) less frequent although severe/steroid refractory myositis; (2) less common mechanic's hands and calcinosis cutis; (3) both frequent and severe ILD. Taken together, our findings suggest that PM/DM patients should routinely undergo the search for anti-PL12 antibody as this autoantibody appears to impact patients' prognosis. Furthermore, ILD patients with anti-PL12 antibody should routinely undergo clinical screening for underlying ASS.