Prospective study of blood viral load of Epstein-Barr virus, herpes virus type 6 and human parvovirus B19 in Crohn's disease: Does therapy matter?

Abstract

The interplay between inflammatory bowel disease (IBD) and DNA viruses, such as Epstein-Barr (EBV), human parvovirus B19 (HPVB19) and human herpes type 6 (HHV6) is scarcely studied. The main aim of this prospective study is to screen for EBV, HSV6, and HPVB19 DNA viremia in adult patients with stable Crohn's disease (CD), correlating the results with IBD treatment. From July 2015 - March 2017, 100 patients were enrolled and divided in four groups of 25 participants each, according to in course treatment. Blood collections were performed every 5 months in all patients. Antibodies for EBV and HPVB19 were screened and repeated if negative. Blood EBV DNA, HPVB19 DNA, and HHV6 DNA were quantified by quantitative real-time Polymerase Chain Reaction. Patients had evidence of EBV (100 %) and HPVB19 (70 %) past infection. Across the study timeline, EBV-DNA, HPVB19-DNA, and HHV6-DNA were detected in the blood of 25, 11, and 7 patients, respectively. Viremia was detected only once in 72 %, 73 %, and 86 % of the patients in the studied period, for EBV, HPVB19, and HHV6, respectively. We did not find significant differences between treatment groups, independently of the viral cut-off for the three viruses. The detection of EBV, HPVB19, and HHV6 viremia, in stable CD patients, was not impacted by biological/immunosuppressant therapy. Although attractive as a non-invasive technique, this approach did not prove to be useful in stable patients. More and larger studies are needed to address the relevance of these viruses on IBD course, in stable patients and during exacerbations.