Interstitial lung disease (ILD) is a common manifestation of systemic autoimmune diseases such as rheumatoid arthritis (RA), lupus and scleroderma, which can lead to inflammation and scarring of the lung and, consequently, to hypoxemia, pulmonary hypertension and death. It is estimated that ILD occurs in approximately 15 percent of patients with RA. Very little is known about how ILD disorders arise and what role loss of immune tolerance plays in ILD development. Presently, there are no validated lung-specific autoantigens for diagnosis of autoimmune-mediated lung disease. Current options for ILD treatment are limited to powerful immunosuppressive medications with significant side effects. Identification of novel pulmonary biomarkers is sorely needed to develop better diagnostic methods and therapies for ILD.