Myositic panel in interstitial lung disease

<bold>Background:</bold> The clinical practice guidelines of ATS/ERS/JRS/ALAT about diagnosis of idiopathic pulmonary fibrosis recommanded, in the cases of ILD of unknown cause, systematic testing for myositis panel. <bold>Objectives:</bold> We aim to investigate the profile of patients presenting ILD of unknown cause, to whom systematic dot-myositis has been practiced. We also compared the positive myositis panel group (group 1) to the negative myositis panel group (group 2). <bold>Methods:</bold> We present a retrospective study of patients with ILD of unknown cause explored in a department of internal medicine. Dot-myositis was practiced to all these patients. <bold>Results:</bold> Our study included 111 patients. Dot myositis was positive in 26 cases (23%). The main positive antibodies were anti-jo1 (9 cases), anti-PM-Scl (5 cases), anti-ku (4 cases), anti-Pl7 (4 cases), anti- MDA5 (2 cases), anti-Mi2b (2 cases), anti-Pl12 (1 case), and anti-oj (1 case). We compared group 1 to group 2. The sex ratio was 0,44 vs 0,54. We noted pulmonary symptoms in 81% vs 95% of the patients (p=0,031). The significantly different manifestations were proximal muscuclar weakness in 27% vs 1% of the cases (p=0), arthralgias in 34% vs 16% (p=0,049), and major dystrophies in the capillaroscopie in 26% vs 2,6% of the patients (p=0,002). Chest CT scan showed nonspecific interstitial pneumonia in 50% vs 20% of the cases (p=0,003), usual interstitial pneumonia in 11,5% vs 34% (p=0,002), and organizing pneumonia in 15% vs 8% (p=0,28). The positivity of myositis pannel was associated to positive anti-Ro52 (46% vs 8,5% p=0). We also found a positive correlation with nonidioathic ILD forms (92% vs 48% p=0). <bold>Conclusions:</bold> Our study supports the necessity of dot-myositis in the etiological investigation of ILD.