Listeria infections associated with infliximab: case reports

Infliximab is a human-murine chimeric monoclonal antibody directed against tumor necrosis factor α (TNFα). Infliximab and other TNF blockers are used to treat inflammatory diseases such as rheumatoid arthritis (RA). TNF blockers are suspected to play a key role in some infections. We report here two cases of Listeria monocytogenes sepsis associated with infliximab treatment for RA. The first patient developed a terminal ileitis and a bacteraemia after three doses of infliximab; the second RA patient presented a bacteraemia associated with a prosthetic joint arthritis of the left hip, both related to Listeria. Those two cases occurred in a population of 518 patients treated with TNF blockers in our hospitals since the year 2000. Those events are of particular interest because of the severity of the infection, because the treatment differs from other infections, and because that, in the rheumatology unit, septic arthritis can mimic RA symptoms. They enhance the likelihood for this drug to increase the risk for infections with germs like Listeria.