Rapidly Progressive Interstitial Lung Disease Associated with Melanoma Differentiation-Associated Gene 5 Antibody.

Anti-melanoma differentiation-associated gene-5 (MDA-5) antibody is an autoantibody found in patients with dermatomyositis. These antibody-positive patients are clinically characterized by complications of rapidly progressive interstitial pneumonia resistant to treatment and with poor prognosis. We describe herein a patient with MDA-5 antibody-positive interstitial lung disease, which progressed rapidly to death after a period of slow progress. Recently, attention has been paid to the similarities in clinical courses and CT images between MDA-5 antibody-positive interstitial lung disease and coronavirus disease 2019 (COVID-19)-associated pneumonia. Patients with MDA-5 antibody do not always have diffuse and evenly distributed bilateral opacities at the time of first presentation. This patient had significant laterality of such opacities. It should be considered that MDA-5 antibody-positive patients with such laterality in opacities might progress rapidly. Chest physicians, dermatologists, and dermatologists need to be aware of the characteristics of the disease for optimal treatment choices.

Lung cancer and combined pulmonary fibrosis and emphysema with anti-ARS antibody.

A 59-year-old man who had smoked for 23 pack-years was admitted to our hospital because of two-month history of back pain. The chest computed tomography scan demonstrated combined pulmonary fibrosis and emphysema (CPFE) and an irregular shaped nodule in the left lower lobe of the lung. A biopsy obtained from samples from subcarinal lymph nodes revealed non-small cell lung cancer. Anti-aminoacyl-tRNA synthetase (ARS) antibody was elevated up to 166 U/mL, although he had no symptoms suggestive connective tissue diseases. It is well known that most of CPFE patients are current or former heavy smokers, and some researchers described the relationship between CPFE and connective tissue diseases. To our best knowledge, this was the first report of lung cancer in patient with anti-ARS antibody-positive CPFE. In some anti-ARS antibody-positive patients, smoking might have a relationship with development of CPFE and lung cancer.