Exacerbation of interstitial lung disease during etanercept therapy: Two cases.

We report two cases of interstitial lung disease possibly related to TNF alpha antagonist therapy (etanercept) in patients with rheumatoid arthritis. In both cases, pre-existing interstitial lung disease worsened during etanercept therapy. We found 19 previously published cases of interstitial lung disease in patients who were taking TNF alpha antagonists and had no evidence of infection, raising the possibility of a causal link with the medication. The potential pathophysiological mechanisms remain unknown. Caution is in order when using TNF alpha antagonists in patients with pre-existing lung disease. The development or exacerbation of interstitial lung disease in a patient on TNF alpha antagonist therapy should lead to investigations for a cause. Should these investigations prove negative, the treatment must be discontinued.