Tropheryma whippelii DNA in saliva of patients without Whipple's disease

Tropheryma whippelii is the causative agent of Whipple's disease, a difficu lt to diagnose systemic illness. Amplification of part of its 16S ribosomal RNA gene(s) has become a standard diagnostic method because of increased s ensitivity as com pa red to classical histopathological analysis. Recently, we demonstrated the presence of T. whippelii DNA by PCR in duodenal biopsi es and/or gastric juice of a considerable fraction of individuals without c linical signs of Whipple's disease. In this follow-up study, saliva and den tal plaques of the same patients were screened for the presence of T. whipp elii DNA. Six out of the 14 previously PCR-positive persons but none of the 17 controls had T. whippelii DNA in their saliva. Our results suggest that Whipple bacteria are ubiquitous environmental or commensal organisms causi ng Whipple's disease only in a particular subset of individuals, possibly t hose with an as yet uncharacterized immunological defect.