Researchers have identified a key target of the immune response that causes type 1 diabetes. Type 1 diabetes is an incurable autoimmune disease caused by the destruction of insulin-producing beta cells in the pancreas by immune cells called T cells.

This study, published in the journal PNAS (Proceedings of the National Academies of Sciences).

A specific type of T cell, a CD4+ T cell, recognizes a part of the beta cell (called an antigen) as foreign, initiating the immune response. Researchers have long been searching for the identity of the antigen that drives the disease.

Earlier work from A/Prof Mannering’s group showed that CD4+ T cells in the pancreas of an organ donor who had type 1 diabetes responded to a specific part of insulin’s precursor, proinsulin, known as C-peptide.

Type 1 Diabetes Diagnosis

They showed that the blood is taken from the arm of people with recent-onset type 1 diabetes contained T cells that recognized C-peptide. They showed that C-peptide was recognized by CD4+ T cells from the blood of more than 60% of people with recently diagnosed type 1 diabetes, but in less than 10% of people without the disease.

In addition, C-peptide was found to be presented to CD4+ T cells by specific cell-surface proteins already known to be associated with a high risk of developing type 1 diabetes. Dr. So says that someone with type 1 diabetes must constantly be aware of their blood glucose levels, which are influenced by the amount of insulin in their system, as well as other factors like stress and illness.

While insulin injections or infusion keep a person with type 1 diabetes alive, they don’t cure the disease or prevent long-term complications in people who are unable to keep their blood glucose within target levels. If we could curb the immune system before the insulin-producing cells are destroyed, this would represent a huge step forward.