Aims/hypothesis: The purpose of this study was to investigate whether the gut mucosa is a reservoir for enterovirus persistence in patients with type 1 diabetes.
Methods: Small intestine biopsy samples from 25 individuals at different stages of type 1 diabetes, 21 control individuals and 27 individuals with coeliac disease were analysed for the presence of enterovirus RNA by using both radioactive in-situ hybridisation and real-time RT-PCR and for the presence of enterovirus proteins by immunostaining with antibodies against VP1 and VP4-2-3 capsid proteins and virus polymerase. Lymphocytic enteropathy and serum anti-VP1 antibodies were also evaluated at the time of biopsy. Moreover, high-throughput sequencing was performed to identify viral transcripts or genomes.
Results: Enterovirus was not detected by in-situ hybridisation or RT-PCR in any of the individuals tested. Immunohistology revealed a few stained cells in the intestinal epithelium in a low number of individuals, with no difference between diabetic and non-diabetic individuals. Levels of serum IgG against VP1 did not differ between control individuals and those with diabetes or coeliac disease and no evidence of diabetes-related lymphocytic enteropathy was detected. High-throughput sequencing did not reveal specific enterovirus sequences in the gut mucosa of individuals with type 1 diabetes.
Conclusions/interpretation: Prolonged/persistent enterovirus infections in gut mucosa are not common in patients with type 1 diabetes.