Interstitial pneumonitis associated with infliximab therapy without methotrexate treatment

Tumor necrosis factor (TNF)-α inhibitors are increasingly being used to treat rheumatoid arthritis. Infliximab (INF) is a TNF-α inhibitor that is usually used in combination with methotrexate (MTX). Interstitial lung disease (ILD) during combination therapy has been attributed to MTX rather than INF. However, INF-associated ILD without combination with MTX has recently been reported. We describe herein a case of severe ILD secondary to INF without MTX therapy.