Interstitial lung disease and myositis-specific and associated autoantibodies: Clinical manifestations, survival and the performance of the new ATS/ERS criteria for interstitial pneumonia with autoimmune features (IPAF).

OBJECTIVE: to describe the clinical manifestations and survival of patients with ILD and myositis-specific and associated autoantibodies, and to evaluate the performance of the new ATS/ERS classification criteria for IPAF.

PATIENTS AND METHODS: Patients with ILD and positive in at least one of the following autoantibodies: anti-Jo-1, anti-Ej, anti-PL7, anti-PL 12, anti-PM/SCL 75 and anti-PM/SCL100 were included. Patients were separated into three groups according to their autoantibody profile: 1. Jo-1 positive patients, 2. Non-Jo-1 antisynthetase autoantibody positive patients, and 3. PM/SCL positive patients. Relevant clinical characteristics were registered. Patients were evaluated had they fulfilled Bohan and Peter's criteria (BPC) for inflammatory myopathies. We evaluated the performance of the IPAF ATS/ERS proposal to classify as such the patients that did not fulfilled BPC, and evaluated whether IPAF patients had a worse survival that BPC patients.

RESULTS: Sixty-eight patients were included. Jo-1 was the most frequent autoantibody (65%), followed by non Jo1 anti-synthetase autoantibodies (31%). Non-Jo1 patients had lower Creatin Kinase serum levels at the baseline and less frequency of arthritis. Only 50% of patients fulfilled BPC. All patients not complying with BPC did comply with IPAF criteria. There was no difference in survival between IPAF and BPC patients. Anti Jo-1 positive was associated to survival and the extent of lung inflammation was associated to mortality.

CONCLUSIONS: Patients differ in clinical manifestations according to the autoantibody profile. All patients not complying with BPC did comply with the new IPAF criteria. There was no difference in survival between BPC and IPAF patients. Jo-1 patients had a better survival. Extent of lung inflammation was associate to mortality.