Interstitial Lung Disease Associated with Anti-PM/Scl or Anti-Aminoacyl-tRNA Synthetase Autoantibodies: A Similar Condition?

Objective. To compare anti-PM/Scl autoantibody-associated interstitial lung disease (ILD) with anti-aminoacyl-tRNA synthetases (anti-ARS) autoantibody-associatecl ILD. Methods. We retrospectively studied 21 patients with ILD from a department of respiratory medicine, including. 9 with anti-PM/Scl autoantibodies (6 women, median age 55 yrs, followup 5.5 yrs) and 12 with anti-ARS autoantibodies (6 women, median age 59 yrs. followup 2.3 yrs). Results. Pulmonary manifestations in patients with anti-PM/Scl autoantibody-associated ILD usually followed the extrapulmonary manifestations of the connective tissue disease (CTD) (7/9 cases). The predominant imaging features on initial high resolution computed tomography were ground-glass attenuation and reticular opacities, and mainly suggested nonspecific interstitial pneumonia in both groups. CTD was classified as dermatomyositis (DM; 2), undifferentiated CTD (2), cutaneous limited systemic sclerosis (2), rheumatoid arthritis (RA; 1), and overlap syndrome (1) in the anti-PM/Scl group; and polymyositis (4), undifferentiated CTD (5), DM (1), amyopathic DM (1), and RA (1) in the anti-ARS group. Frequencies of arthralgia, Raynaud phenomenon, cutaneous rash, and mechanic's hands were comparable in both groups. Myalgia or muscle weakness was present in 0/9 PM/Scl and 5/12 ARS patients (p < 0.05). More than 1 autoantibody was present in 11 patients. ILD worsened despite treatment in 4 patients with anti-PM/Scl autoantibodies and 2 with anti-ARS autoantibodies, and included I death. Conclusion. Anti-PM/Scl and anti-ARS antibodies are associated with similar clinical manifestations, with the exception only of more overt myositis in the latter, therefore challenging the clinical specificity of the antisynthetase syndrome. (First Release March 15 2010; J Rheumatol 2010; 37:1000-9; doi:10.3899/jrheum.090652)