Issue: February 2017
January 10, 2017
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Excess enterovirus infections observed in children with type 1 diabetes

Issue: February 2017
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Children with type 1 diabetes were found to have had three times the number of enterovirus infections as children without diabetes, study findings show.

“This is the first time that the detection of enteroviruses in the stool samples of young children was found to be associated with the initiation of the beta-cell damaging process,” Heikki Hyöty, MD, PhD, professor of virology at the School of Medicine, University of Tampere, Finland, told Endocrine Today. “In addition, there seems to be several months’ time lag between the infection and the initiation of the disease process. The long time lag supports slowly operating mechanisms in virus-induced autoimmunity.”

Heikki Hyoty
Heikki Hyöty

Hyöty and Hanna Honkanen, MSc, PhD, of the department of virology at the University of Tampere, Finland, and colleagues analyzed serial stool samples collected longitudinally from children participating in the Type 1 Diabetes Prediction and Prevention (DIPP) study in Finland, which included children with human leukocyte antigen (HLA) class II genotypes, conferring an increased susceptibility to type 1 diabetes (about 12% of all newborns). Researchers analyzed 1,673 stool samples from 129 children who tested positive for multiple islet antibodies (cases) and 3,108 stool samples from 282 children without diabetes matched for area of residence, sex, HLA-DQ genotype and time of birth (controls). All samples were screened for enterovirus RNA; viral genotype was detected by sequencing.

Researchers found that case children had more enterovirus infections than control children (mean 0.8 vs. 0.6 infections per child). In time-dependent analysis, researchers found the excess of infections in case children occurred more than 1 year before the first autoantibody-positive sample; during this time, a mean of 0.62 infections were diagnosed per case child vs. 0.33 infections diagnosed per control child (mean, 6.3 vs. 2.1 infections per 10 follow-up years). This difference was not observed for infections occurring less than 1 year before autoantibody-positive samples.

None of the individual enterovirus types was associated with islet autoimmunity, according to researchers.

“It seems that these viruses can directly infect insulin-producing cells in the pancreas,” Hyöty said. “The infection may become chronic and induce inflammation, which promotes autoimmune responses to insulin and other autoantigens. However, further studies are needed to elucidate the underlying mechanisms in more detail.”

The researchers noted that studies are in progress in different countries exploring the association.

“It will also be important to explore the possibility of creating a vaccine against these viruses to find out whether it could prevent type 1 diabetes,” the researchers wrote. – by Regina Schaffer

Disclosure: Sanofi Pasteur and Vactech Ltd. partly funded this study. Two of the researchers are minor (5%) shareholders and members of the board of Vactech Ltd., which develops vaccines against picornaviruses.