Diabetes mellitus type 1 - What does this mean and what happens in our body? There are many books about "diabetes mellitus type 1". It is an autoimmune disease, with destruction of the beta cells in the pancreas. Therefore insulin is no longer produced and blood glucose is rising. But: what exactely happens in the body? In the stories you will find simple and understandable explanations. This book is dedicated to all children with "type 1 diabetes".