Type 1 diabetes is a condition that is caused in part by an abnormality of the immune system which occurs when T cells, which are part of the immune system, damage the insulin secreting cells (islet cells) in the pancreas. Although it is known that T cells are important mediators of the disease, progress in the development of reliable T cell assays has been modest. The purpose of this study is to learn which T cell assays are most reliable and reproducible so that the investigators can improve their understanding about how type 1 diabetes occurs.

The T Cell Validation Study is designed to determine the ability of T cell assays to identify differences in responses from participants with type 1 diabetes compared to normal control subjects, and to compare four different laboratory tests which examine T cells to determine whether the measurements are quantitatively reproducible.

Antibody assays that confirm the presence of type 1 diabetes will be evaluated including: Diabetes Biochemical Autoantibody Assay (anti-GAD65, anti-ICA512, anti-insulin) and Islet Cell Autoantibody testing; genetic testing (deoxyribonucleic acid [DNA] and human leukocyte antigen [HLA]) will also be done to learn more about the T cell assays.

The following T Cell Assays will be conducted in individuals with type 1 diabetes, as well as those without type 1 diabetes:

• Cellular Immunoblot Testing
• T Cell Proliferation Assay
• Tetramer Assay
• Cytokine ELISpot Assay

Inclusion Criteria:

To be eligible, individuals with type 1 diabetes must be:

• Diagnosed with type 1 diabetes within one year of first study visit
• 8-35 years of age at time of first visit
• Weigh > 40 kg (88 lbs) at time of first visit
• Individuals who will serve as control subjects who do not have type 1 diabetes cannot have a first degree or second degree relative with type 1 diabetes.

Exclusion Criteria:

Individuals must not:

• Have any major illness
• Be taking any steroid medications
• If female, should not be pregnant or breastfeeding.