PCR analysis in the pathological diagnosis of Whipple's disease: Emphasis on extraintestinal involvement or atypical morphological features

PCR analysis of species-specific bacterial 16S rRNA. gene of Tropheryma whi ppelii was performed in biopsies from 10 cases of Whipple's disease (WD). I n seven patients showing the typical clinical picture of WD, PCR was perfor med an the diagnostic intestinal biopsy. In the remaining three casts (an a utopsy. case of disseminated WD and two patients showing lymphadenopathy as the initial clinical presentation), PCR was done on lymph node specimens. In one of the lymph node biopsies, an unusual sarcoidlike granulomatous rea ction had led to the diagnosis of sarcoidosis. The specific bacterial DNA w as detected in all cases, both in intestinal biopsies and in lymph node spe cimens. Follow-up biopsies after antibiotic therapy were evaluated in two p atients, The two follow-up biopsies were negative, although in both of them scattered nests of PAS-positive macrophages remained. The results of this study suggest that PCR analysis of species-specific sequences of the 16S rR NA of Tropheryma whippelii is a very useful tool for the pathological diagn osis of WD. It confirms the diagnosis of WD in intestinal biopsies as well as in extraintestinal sites, even when the morphological appearance is not typical. It is also the most precise technique for monitoring therapeutic e ffects. (C) 1999 John Wiley & Sons, Ltd.