Enterovirus genomes in the blood of children with T1DM at disease onset and one year later

Background: Enteroviral (EV) infections have been proposed as one triggering environmental factor leading to T1DM. The mechanism(s) through which EV collaborate to beta cell destruction is still unclear. Human EV have long been known as agents of acute diseases, chronic infections being rarely documented. Objectives and hypotheses: To assess whether T1DM were associated with chronic EV infection, we evaluated the presence of EV RNA genomes both at the time of clinical onset and one year later. Population and/or methods:blood samples of 68 T1D patients (38 boys; age 2-18 years) have been investigated. Detection of EV genomes was performed by RT-PCR using different primer pairs directed to conserved genomic regions. Sensitivity of the amplification methods in use was ?10 genome equivalents per reaction tube. Direct sequencing of purified amplicons allowed identifying EV at the species level. Results: at onset, EV genomes were detected in 46/68 patients (67%). No viral genomes were detected in 18 healthy control children. Direct amplicon sequencing showed that viruses of the HEV-B and HEV-C species were particularly prevalent. Retesting positive patients one year after clinical onset showed that EV genomes were present in only 1/46 children. Conclusions: The results confirm the temporal association of EV infection with the onset of T1DM. We were unable to show persistent EV infection in the blood of most pediatric patients. This, however, does not exclude chronic infection of pancreatic islets.