Human herpesvirus 6 in biopsies from patients with gastrointestinal symptoms after allogeneic stem cell...

Gastrointestinal complications are frequent after allogeneic stem cell transplantation (allo-SCT). Main differential diagnoses are graft-versus-host disease (GvHD) and viral infections. In this retrospective analysis, we included 50 patients with severe vomiting or diarrhea in the first year after allo-SCT. One hundred two biopsies obtained by colonoscopy or endoscopy of the upper gastrointestinal tract were analysed by conventional histology for signs of GvHD and by qualitative polymerase chain reaction (PCR) for viral DNA of human herpesvirus 6 (HHV-6) and other virus of the herpes family. DNA of HHV-6 was detected in 38 of 75 initial samples (51%) and in 19 of 27 follow-up biopsies (70%). In the initial samples (n = 75), HHV-6 DNA was detected in 20/37 (54%) biopsies in the presence of GvHD compared to 18/38 (47%) biopsies without signs of GvHD. At the time of the first endoscopic investigation, most patients received antiviral prophylaxis with aciclovir. None of the follow-up biopsies was HHV-6 DNA negative after antiviral treatment with aciclovir, foscarnet or ganciclovir. By univariate analysis, no risk factor for HHV-6 detection could be demonstrated. In this cohort of patients with severe gastrointestinal complications, there was no significant difference in the overall survival between patients with or without HHV-6 DNA detection in the gastrointestinal tract. In summary, the detection of HHV-6 DNA had no impact on overall survival. Moreover, antiviral therapy against HHV-6 was without effect. Thus, positive PCR results in GI tract samples do not necessarily reflect reactivation of HHV-6. Further studies are needed to define the significance of HHV-6 for GI tract symptoms after allo-SCT.