Interstitial lung disease associated with anti-citrullinated peptide/ protein antibody-positive anti-synthetase syndrome

Little has been reported on the characteristics of interstitial lung disease (ILD) associated with anti-citrullinated peptide/protein antibody (ACPA)-positive anti-synthetase syndrome (ASS). We sought to investigate the clinical, radiologic, and pathologic features of patients with ILD associated with ACPA-positive ASS. Medical records of seven ILD patients with positive results of both ACPA and anti-aminoacyl-tRNA synthetase antibody were retrospectively reviewed. Five patients had clinical symptoms associated with ASS other than ILD. On high-resolution computed tomography (HRCT) analysis, a nonspecific interstitial pneumonia (NSIP) pattern was shown in 3 patients and NSIP with organizing pneumonia (OP) overlap in 2 patients. Coronal slices of these 5 patients showed lower lung disease predominance with traction caudally on major fissures due to lower lobe volume loss. These were features that could commonly be observed in ASS-associated ILD. Pathological findings available for 3 patients showed NSIP. The characteristics of ILD associated with ACPA-positive ASS appear to be similar to those of ILD associated with ASS, but not to rheumatoid arthritis (RA) or ACPA, especially in terms of the radiological findings.