In this study, we are investigating the effect of transient hypoglycaemia on the genome of immune cells (CD8+ T cells) in people with type 1 diabetes. Cells of the adaptive immune system are able to react much faster and more efficiently to a pathogen they have encountered before. This process is called "immunological memory". Memory cells differ from normal defense cells not only in their function but also in their metabolism. In earlier studies, we were able to show that immune cells can not only detect pathogens, but also react to their metabolic products. High blood sugar levels can lead to permanent changes in the genetic material of cells of the blood vessel system. Whether blood glucose levels trigger similar changes in cells of the immune system and whether this effects their function will be investigated in this study.