Interstitial lung disease, a common manifestation of newly diagnosed polymyositis and dermatomyositis

Abstract

Objectives: To estimate the prevalence and predictors of interstitial lung disease in newly diagnosed polymyositis and dermatomyositis. Methods: A prospective study in which consecutive patients with newly diagnosed poly-and dermatomyositis, regardless of clinical symptoms of pulmonary disease, were investigated with chest x ray, high resolution computed tomography (HRCT), pulmonary function tests, and biochemical and autoantibody analysis. Patients with inclusion body myositis, malignancy, other defined inflammatory connective tissue diseases (CTDs), or antibody profile indicating other CTDs were excluded. Results: Between March 1998 and September 2000, 26 new cases of poly-or dermatomyositis were diagnosed; 17 of those patients were included in the study. Interstitial lung disease (ILD), defined as radiological signs on chest x ray examination/HRCT or restrictive ventilatory defect, were found in 11 (65%) patients and were more common in men than in women. Arthritis and occurrence of anti-Jo-1 antibodies were found more often in patients with ILD than in those without. There was no statistically significant association between respiratory symptoms, other serological or laboratory variables and ILD. Conclusions: ILD is a common early manifestation in patients with poly-and dermatomyositis and is not always related to clinical symptoms. Chest x ray examination, HRCT, pulmonary function tests, and analysis of anti-Jo-1 antibodies should be included in the initial investigation of patients with myositis regardless of respiratory symptoms. P olymyositis (PM) and dermatomyositis (DM) are systemic inflammatory disorders with unknown aetiology and pathogenesis. They mainly affect striated muscles, resulting in proximal muscle weakness. However, other organ systems, including the lungs, may be affected, and pulmonary complications are associated with high morbidity and mortality.

Restricted T cell receptor BV gene usage in the lungs and muscles of patients with idiopathic inflammatory myopathies

“…We cannot exclude a selection bias of patients with clinical or subclinical lung involvement who agreed to participate in the study, but still, it is likely that subclinical lung involvement in PM and DM is more common than has previously been reported and that this becomes evident when highly sensitive methods such as HRCT are used. The high frequency of clinical or subclinical ILD in patients with PM and DM was recently reported by us (14) and by other investigators (40). All 9 patients in our study fulfilled the Bohan and Peter criteria for definite or probable PM or DM at study entry, but at followup after 1 year, 1 patient (patient 9) fulfilled the criteria for IBM.…”

“…Lung function was measured using a standard protocol as described previously (14) and included dynamic spirometry, static lung volumes, and transfer factor measured by single-breath diffusing capacity for carbon monoxide (DLCO) corrected for alveolar volumes. The results are expressed as the percentage of predicted values for the patient's age, height, and sex, using standard reference values (18,19).…”

“…Chest radiography and highresolution computed tomography (HRCT) of the lungs were performed as described previously (14). Radiographic abnormalities consistent with ILD were defined as the presence of linear opacities, subpleural lines, ground-glass opacities, consolidation, traction bronchiectasis, and honeycombing.…”

“…A major clinical problem in both PM and DM is pulmonary involvement. Interstitial lung disease (ILD) has been reported to be present in as many as 65% of newly diagnosed patients with PM and DM (14). Certain myositis-specific autoantibodies are strongly associated with ILD, in particular, the Jo-1 antibody (15).…”

A possible mechanism for endogenous activation of the type I interferon system in myositis patients with anti–Jo‐1 or anti–Ro 52/anti–Ro 60 autoantibodies

“…The same mechanism could also be of relevance for anti-Ro 52/anti-Ro 60 autoantibodies in myositis, and anti-Ro 52 antibodies frequently co-occur with anti-Jo-1 antibodies (29). We also found a correlation between the IFN␣-inducing capacity of sera and the presence of ILD, one of the major extramuscular features of anti-Jo-1 antibodypositive patients (3,30), suggesting that IFN␣ production could have a role in the development of ILD in these patients. Another explanation could be that IFN␣ induction and ILD independently correlate with the presence of anti-Jo-1 antibodies.…”