T Cell Repertoire Diversity Is Decreased in Type 1 Diabetes Patients

Type 1 diabetes mellitus (T1D) is an immune-mediated disease. The autoreactive T cells in T1D patients attack and destroy their own pancreatic cells. In order to systematically investigate the potential autoreactive T cell receptors (TCRs), we used a high-throughput immune repertoire sequencing technique to profile the spectrum of TCRs in individual T1D patients and controls. We sequenced the T cell repertoire of nine T1D patients, four type 2 diabetes (T2D) patients, and six nondiabetic controls. The diversity of the T cell repertoire in T1D patients was significantly decreased in comparison with T2D patients (P=7.0E-08 for CD4⁺ T cells, P=1.4E-04 for CD8⁺ T cells) and nondiabetic controls (P=2.7E-09 for CD4⁺ T cells, P=7.6E-06 for CD8⁺ T cells). Moreover, T1D patients had significantly more highly-expanded T cell clones than T2D patients (P=5.2E-06 for CD4⁺ T cells, P=1.9E-07 for CD8⁺ T cells) and nondiabetic controls (P=1.7E-07 for CD4⁺ T cells, P=3.3E-03 for CD8⁺ T cells). Furthermore, we identified a group of highly-expanded T cell receptor clones that are shared by more than two T1D patients. Although further validation in larger cohorts is needed, our data suggest that T cell receptor diversity measurements may become a valuable tool in investigating diabetes, such as using the diversity as an index to distinguish different types of diabetes.