What is T1D?

T1D is a chronic autoimmune condition in which the pancreas is unable to produce insulin due to autoimmune destruction of β cells by autoreactive T lymphocytes.1,2


More than 10% of the United States’ population has diabetes3
  • T1D makes up 6% of this group3
  • Though they often are grouped together, T1D has an autoimmune origin, type 2 diabetes is a metabolic disease4

How does autoimmunity arise?

As a result of β-cell infection, and in genetically predisposed patients, the immune system becomes “intolerant” of self. T cells attack and destroy β cells and lead to a lack of insulin production. In addition, T cells activate B cells, which produce autoantibodies to autoantigens on the pancreatic β cells, including insulin itself. The immune system then recognizes β-cell proteins as autoantigens, so it attacks β cells.5


The body’s regulation of blood glucose depends in part on β cells in the islets of Langerhans of the pancreas, which sense glucose levels and secrete insulin to prevent major swings in glucose levels.6


In T1D, the pancreas is unable to produce insulin due to autoimmune destruction of β cells by autoreactive T lymphocytes.6

T1D Illustration

What is C-peptide?

Measuring C-peptide levels

Measuring C-peptide levels is an important method to gauge β-cell function7

C-peptide levels

C-peptide levels correlate with insulin secretion and are used to assess β-cell function7

What causes T1D?

T1D has both genetic and environmental causes:

  • Approximately 15% of those with T1D have a first-degree relative (parent, sibling, or child) with the disease8

  • Several viral infections including coxsackie B, enterovirus, rotavirus, influenza, mumps, and rubella are theorized as possible triggers for T1D9

1. Medline Plus. Type 1 diabetes. https://medlineplus.gov/ency/article/000305.htm. Published August 4, 2020. Accessed August 17, 2020. 2. Burrack AL, Martinov T, Fife BT. T cell-mediated beta cell destruction: autoimmunity and alloimmunity in the context of type 1 diabetes. Front Endocrinol. 2017;8:343. 3. Centers for Disease Control and Prevention. National Diabetes Statistics Report, 2020. https://www.cdc.gov/diabetes/pdfs/data/statistics/national-diabetes-statistics-report.pdf. Accessed August 17, 2020. 4. American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care. 2014;37(suppl 1):S81-S90. 5. Xie Z, Chang C, Zhou Z. Molecular mechanisms in autoimmune type 1 diabetes: a critical review. Clin Rev Allerg Immunol. 2014;47(2):174-192. 6. Bluestone JA, Herold K, Eisenbarth G. Genetics, pathogenesis and clinical interventions in type 1 diabetes. Nature. 2010;464(7293):1293-1300. 7. Leighton E, Sainsbury CA, Jones GC. A practical review of C-peptide testing in diabetes. Diabetes Ther. 2017;8(3):475-487. 8. Beck RW, Tamborlane WV, Bergenstal RM, Miller K, DuBose SN, Hall CA; for T1D Exchange Clinic Network. J Clin Endocrinol Metab. 2012;97(12):4383-4389. 9. Smatti MK, Cyprian FS, Nasrallah GK, Al Thani AA, Almishal RO, Yassine HM. Viruses and autoimmunity: a review on the potential interaction and molecular mechanisms. Viruses. 2019;11(8):1-18.