Abstract: Objective To investigate the change in the ratio of CD8⁺CD25⁺ regulatory T cells (Treg) in peripheral blood in the elderly patients with type 2 diabetes mellitus (T2DM), and to investigate the relationship with insulin resistance. Methods From April 2019 to September 2020, 42 elderly patients with T2DM and 40 healthy elderly who underwent physical examination in our hospital were selected and divided into the study group and the control group, respectively. The general data, biochemical indicators, CD8⁺CD25⁺Treg ratio and insulin resistance index (HOMA-IR) of the two groups were compared. Pearson correlation analysis was used to explore the relationship between the change of CD8⁺CD25⁺Treg ratio and HOMA-IR in the elderly patients with T2DM. Results The levels of body mass index (BMI), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG), postprandial 2 h plasma glucose (2hPG), glycosylated hemoglobin (HbA1c) and fasting insulin (FINS) in the study group were higher than those in the control group (P<0.05). The level of HOMA-IR in the study group was higher than that in the control group (P＜0.01), and the ratio of CD8⁺CD25⁺Treg was lower than that in the control group (P＜0.01). CD8⁺CD25⁺Treg ratio was negatively correlated with HOMA-IR and FINS (r=-0.506, -0.382, P＜0.05). Conclusions Compared with healthy elderly, the ratio of CD8⁺CD25⁺Treg in elderly T2DM patients is abnormally lower, which may be related to insulin resistance in elderly T2DM patients.

Key words: aged, type 2 diabetes mellitus, regulatory T cells, insulin resistance