Echinococcus multilocularis infection and TNF inhibitor treatment in a patient with rheumatoid arthritis

Sir, TNFa blocking agents should not be used in patients with high risk of infections whose containment is macrophage/ granuloma dependent, such as mycobacteria, coccidiomycosis or histoplasmosis [1]. In echinococcosis, Th1 cytokines are also important for host defense [2, 3]. It has been shown that TNFa mRNA is located in macrophages in the periparasitic area of the liver [4] leading to the development of an intrahepatic granuloma surrounding the parasite tissue [5]. Otherwise, antibody production in early infection may be stimulated by a T-cell independent mechanism [6]. However, to our best knowledge, cases of the evolution of echinococcosis during TNF inhibitor treatment have not been reported so far. We present a patient with rheumatoid arthritis (RA), who developed echinococcus abscess for