Today at EASD Professor Noel Morgan, from the Peninsula Medical School in Plymouth, presented his research on the role of viruses in type 1 diabetes.
Professor Morgan and his team analysed pancreatic samples taken from people who had type 1 and compared them to samples from people who did not have type 1. They looked for the presence of enteroviruses, which are a large family of viruses that include the common cold
Over 80% of the samples from people with type 1 had evidence of virus proteins in the remaining beta cells. These viral proteins were not found in any other islet cell. Only 30% of the samples taken from people who did not have type 1 showed evidence of viral infection in beta cells.
Professor Morgan and his team think that in some people, enteroviral infection can trip beta cells into a self-destructive mode – which is good news in the short term, as the virus is destroyed along with the cell. But once the viral infection is gone, the beta cells remain in this destructive mode, meaning that when a rogue immune cell attacks the beta cell, the cell dies straight away, instead of triggering the normal protective mechanism that cells usually employ in these scenarios.
In the same session, Professor Matthias von Herrath presented findings from his research team in California. Interestingly, his work has led to the discovery that some viral infections may have a protective effect against type 1 while others may be detrimental.
His research showed that while some strains of enterovirus seem to be associated with the development of type 1, others may protect against the condition. He found that infection with a low dose of some strains of enterovirus actually improved the immune system’s ability to fight off other infections in the future. It caused an increase in the number of regulatory T cells that were present in the immune system.
In type 1 diabetes, the balance between regulatory and killer T cells is out of kilter, with more killer cells being produced. An increase in the number of regulatory T cells would stop this imbalance occurring.
This research lends support the theory that the immune system gets better the more it is used. Since our environment is a lot cleaner than it used to be, our immune systems’ may not be getting enough practice to allow it to fight things like type 1 diabetes.
Research Communication Officer Maebh Kelly said, ‘There is a lot of research at the moment into the causes of type 1, and how we might prevent it. All of this work on viruses adds to our understanding of the way the immune system works to protect us, and how this goes wrong to lead to type 1 diabetes. But this morning’s presentations show that the picture of the role viruses may play in the development of type 1 is far from clear cut.’