How does diabetes increase infections?

Research led by the Warwick Medical School has found that high blood glucose levels can cause a 'sugar coating' which effectively smothers and blocks the mechanisms the body uses to detect and fight bacterial and fungal infections.
 
People with diabetes suffer from a higher risk of chronic bacterial and fungal infections but until now little has been known about the mechanisms involved. This new research led by Dr Daniel Mitchell at the University of Warwick’s Medical School has found a novel relationship between high glucose and the immune system in humans.

The researchers have found that specialised receptors that recognise molecules associated with bacteria and fungi become 'blind' when glucose levels rise above healthy levels. This new research may also help explain why diabetic complications can include increased risk of viral infections such as influenza and inflammatory conditions including cardiovascular disease.
 
The chemical structure of glucose in blood and body fluids was compared to two other sugars called mannose and fucose in the study. These sugars are found on the surfaces of bacteria and fungi and act as targets for receptors in the body that have evolved to detect and bind to microbial sugars to combat the infection.
 
The research found that high levels of glucose outcompetes the binding of mannose and fucose to the specialised immune receptors, potentially blocking these receptors from detecting infectious bacteria and fungi. Glucose was also found to bind in such a way that inhibits the chemical processes that would normally follow to combat infection.

Warwick Medical School researcher Dr Daniel Mitchell said, 'Our findings offer a new perspective on how high glucose can potentially affect immunity and thus exert a negative impact on health. It also helps to emphasise the importance of good diet in preventing or controlling diseases such as diabetes. We will build on these ideas in order to consolidate the disease model and to investigate new routes to treatment and prevention.'