Rheumatoid lung disease.

Rheumatoid arthritis (RA) is a common, functionally disabling disease with genetic and environmental contributors. It occurs in approximately 1% of the population and adversely affects quality of life, functional status, and survival. Beyond its impact on the joints, pulmonary involvement occurs regularly and is responsible for a significant portion of the morbidity and mortality. Although pulmonary infection and/or drug toxicity are frequent complications, lung disease directly associated with the underlying RA is more common. The airways, vasculature, parenchyma, and pleura can all be involved, with variable amounts of pathologic inflammation and fibrosis. The true adverse clinical impact of the most important of these directly associated disorders, RA-associated interstitial lung disease (RA-ILD), has only recently begun to reveal itself. Our knowledge of the underlying pathobiology and the impact of our current immunomodulatory and biologic therapies on the lung disease are less than incomplete. However, what is clear is the importance of progressive lung fibrosis in shortening survival and impairing quality of life in RA as well as in other connective tissue diseases. The impact of historically available and newer biologic therapies in altering the outcome of RA-ILD is unknown; translational studies focused on the pathobiology and clinical studies focused on the treatment of RA-ILD are needed.