Objective: The objective of this article was to establish the clinical course of interstitial lung disease (ILD) in scleroderma related to the presence of anti-PM/Scl antibody compared with anti-Scl-70 in a Spanish cohort. Furthermore, no study has thoroughly investigated the outcome of pulmonary function test in the first group of patients.
Methods: A total of 63 Spanish patients with scleroderma and ILD were selected in a retrospective observational study. Among them, 14 were positive for anti-PM/Scl antibodies and 49 for anti-Scl-70. Clinical assessments, including pulmonary function test, were collected. Variations equal or greater than 10% in forced vital capacity (FVC) were considered significant. Progression-free survival of disease was defined as the period of stable illness since pulmonary fibrosis diagnosis.
Results: Anti-Scl-70 patients had a higher frequency of diffuse SSc subset, peripheral vasculopathy, and gastrointestinal involvement. Inflammatory myopathy was associated to anti-PM/Scl antibody. Anti-PM/Scl patients presented more improvement in FVC during follow-up, 30.8% compared to a 7.1% in Scl-70 group (P = 0.04), with less worsening of this parameter (15.4% vs 52.4% in Scl-70 patients, P = 0.01), and secondary less frequency of severe restrictive pattern (FVC < 50%) (7.7% compared to 42.9% in the other group, P = 0.02). Regarding treatment, more anticalcineurinics were used in anti-PM/Scl patients, while cyclophosphamide and mycophenolate were mainly used in anti-Scl-70 patients. The progression-free survival of disease was higher in anti-PM/Scl patients, with 76% at 10 years from diagnosis of ILD against a 29% in the Scl-70 group.
Conclusions: Several features and prognosis of ILD in SSc may be modified depending on the identified immunological profile.
Keywords: Anti-PM/Scl antibodies; Anti-topoisomerase I antibodies; Interstitial lung disease; Prognosis; Pulmonary fibrosis; Pulmonary function test; Systemic sclerosis.
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