Introduction: Chronic infection with Tropheryma whipplei, known as Whipple's disease (WD), classically affects the gastrointestinal tract, but any organ system may be affected, and isolated manifestations occur. Reliable diagnosis based on a combination of periodic acid-Schiff (PAS) staining, T. whipplei-specific immunohistochemistry (IHC), and polymerase chain reaction (PCR) from duodenal biopsies may be challenging in cases without classical gastrointestinal infection, so the need for additional diagnostic materials is urgent.
Objective: Our objective was to evaluate additional diagnostic possibilities for WD.
Methods: We analyzed samples from 20 patients with WD and 18 control subjects in a prospective observational pilot study. In addition to WD diagnosis by PAS staining, T. whipplei-specific IHC and PCR of duodenal or extra intestinal tissues, whole EDTA blood, peripheral blood mononuclear cells (PBMCs) and PBMC fractions enriched with or depleted of cluster of differentiation (CD)-14+ cells were examined using T. whipplei rpoB gene PCR.
Results: Tropheryma whipplei DNA was detected in 35 of 60 (58.3%) preparations from 16 of 20 patients with WD, most of whom lacked gastrointestinal signs and characteristic PAS-positive duodenal macrophages.
Conclusion: This study provides evidence for the potential suitability of blood, particularly PBMCs, as material to assist in the diagnosis of WD via rpoB gene real-time PCR. Thus, PCR from blood preparations can be helpful for diagnostic decision making in atypical cases of WD.