Long-term outcome of patients with polymyositis/ dermatomyositis and anti-PM-Scl antibody

BACKGROUND: To date, no series has analysed long-term outcome in patients with polymyositis/dermatomyositis (PM/DM) with anti-PM-Scl antibody. OBJECTIVES: The aims of the present study were: (i) to assess clinical features and long-term outcome, including organ complications, functional course and mortality rate, in patients with isolated PM/DM with anti-PM-Scl antibody; and (ii) to evaluate prevalence, characteristics and long-term outcome of interstitial lung disease (ILD) in patients with isolated PM/DM with anti-PM-Scl antibody. METHODS: The medical records of 20 consecutive patients with isolated PM/DM with anti-PM-Scl antibody were reviewed. RESULTS: Two patients (10%) achieved remission of PM/DM, whereas 14 (70%) improved and four (20%) had a worsened clinical status. Short-term recurrences (during tapering of therapy) occurred in nine patients and long-term recurrences (after discontinuation of therapy) in three patients. Moreover, patients with PM/DM with anti-PM-Scl antibody exhibited severe complications, as follows: oesophageal involvement (n = 4) requiring enteral feeding in three cases, ventilatory insufficiency (n = 3) requiring mechanical ventilation in two cases; three other patients had cancer. Interestingly, patients with PM/DM with anti-PM-Scl antibody often presented symptoms that are usually found in antisynthetase syndrome, i.e. hyperkeratotic rhagadiform hand symptoms (n = 2; 10%), Raynaud’s phenomenon (n = 8; 40%), arthralgia/arthritis (n = 7; 35%) and ILD (n = 12; 60%). In our cohort, the associated ILD often required combined therapy of steroids and immunosuppressive agents. CONCLUSIONS: Our series suggests that the presence of anti-PM-Scl antibody is not a good prognostic factor in patients with PM/DM, as there appears to be an association with lung and oesophageal involvement; in addition, anti-PM-Scl antibody may coexist with malignancy in patients with PM/DM. Furthermore, anti-PM-Scl antibody-positive patients with PM/DM often exhibit ’mechanic’s hands’, Raynaud’s phenomenon and joint involvement. Our latter findings raise the possibility that the immunogenetic background influences the autoantibody status of these patients; HLA-DR3 has, in fact, been found in association with antisynthetase syndrome antibodies and with anti-PM-Scl antibodies.