Whipple's disease.

Whipple's disease is a chronic, systemic infection caused by Tropheryma whipplei. Gene amplification, isolation and DNA sequencing of T whipplei have extended our knowledge of this pathogen, which is now recognised as a ubiquitous commensal bacterium. The spectrum of signs associated with T whipplei has now been extended beyond the classic form, which affects middle-aged men, and begins with recurrent arthritis followed several years later by digestive problems associated with other diverse clinical signs. Children may present an acute primary infection, but only a small number of people with a genetic predisposition subsequently develop authentic Whipple's disease. This bacterium may also cause localised chronic infections with no intestinal symptoms: endocarditis, central nervous system involvement, arthritis, uveitis and spondylodiscitis. An impaired TH1 immune response is seen. T whipplei replication in vitro is dependent on interleukin 16 and is accompanied by the apoptosis of host cells, facilitating dissemination of the bacterium. In patients with arthritis, PCR with samples of joint fluid, saliva and stools has become the preferred examination for diagnosis. Immunohistochemical staining is also widely used for diagnosis. Treatment is based on recent microbiological data, but an immune reconstitution syndrome and recurrence remain possible. The future development of serological tests for diagnosis and the generalisation of antigen detection by immunohistochemistry should make it possible to obtain a diagnosis earlier and thus to decrease the morbidity, and perhaps also the mortality, associated with this curable disease which may, nonetheless, be fatal if diagnosed late or in an extensive systemic form.