Pulmonary granulomas after tumour necrosis factor alpha antagonist therapy.

Tumour necrosis factor alpha (TNFalpha) antagonists are an established therapeutic option in Crohn's disease and rheumatoid arthritis. In recently published studies these agents have been used with great success, but little is known about any side effects or long term consequences. They increase the frequency of infections with mycobacteria, where TNFalpha is thought to be an important host defence factor. We describe one patient who was treated with TNFalpha antagonists and later developed pulmonary granulomas with caseating necrosis without detection of mycobacteria or any other pathogens. Possible mechanisms involved in this newly recognised side effect are discussed.