Abatacept and serious respiratory infections in patients with previous lung disease.

Abatacept is a biologic agent used in the treatment of rheumatoid arthritis, for which underlying chronic obstructive lung disease is listed as a precaution to its use due to concern for increased risk of respiratory adverse events. We describe two cases of severe respiratory complications affecting rheumatoid arthritis patients undergoing treatment with abatacept who had been previously diagnosed with underlying lung disease.