Tumor necrosis factor α (TNFα) has been implicated in the pathogenesis of certain inflammatory diseases. Two TNFα‐neutralizing agents are licensed in the US. Infliximab is licensed for the treatment of Crohn's disease (CD) and, when used with methotrexate, for the treatment of rheumatoid arthritis (RA). Etanercept is licensed for the treatment of RA, including juvenile RA, and, more recently, was licensed for the treatment of psoriatic arthritis. Because of the potential for decreased host resistance to infectious agents due to treatment with anti‐TNFα agents, we sought to evaluate postlicensure cases of opportunistic infection, including Listeria monocytogenes, in patients treated with these products.

The FDA Adverse Event Reporting System, a passive monitoring system, was reviewed to identify all reports of adverse events (through December 2001) associated with L monocytogenes infection in patients treated with infliximab or etanercept.

Fifteen cases of L monocytogenes infection associated with infliximab or etanercept treatment were identified. In 14 of these cases, patients had received infliximab. The median age of all patients was 69.5 years (range 17–80 years); 53% were female. Six deaths were reported. Among patients for whom an indication for use was reported, there were 9 patients (64%) with RA and 5 patients (36%) with CD (information was not reported for 1 patient). All patients for whom information was reported were receiving concurrent immunosuppressant drugs.

Postlicensure surveillance suggests that L monocytogenes infection may be a serious complication of treatment with TNFα‐neutralizing agents, particularly infliximab.