Abstract: Objective  To investigate the changes and significance of circulating CD4+T cell subsets in patients with type 2 diabetes mellitus (T2DM) and diabetic kidney disease(DKD). 
Methods  We recruited 113 patients with newly diagnosed T2DM and 30 healthy volunteers, and compared the differences of the CD4+ T cell subsets, including Th1, Th2 and Tregs, in the peripheral blood of subjects from the three groups. Spearman's rank correlation analysis was conducted to explore the correlation between estimated glomerular filtration rate(eGFR) and CD4+ T cell subsets. Multiple linear regression analysis was used to explore the influencing factors of eGFR changes. 
Results  There were significant differences in the proportion of peripheral blood Th1, Th1/Th2 ratio and the proportion of Tregs among three groups. The Th1 ratio and Th1/Th2 ratio in patients with T2DM and DKD were higher than those of control group, while the proportion of Tregs was lower than that of control group. Moreover, the proportion of Th1 and Th1/Th2 ratio in patients with DKD were higher than those of T2DM group, and the proportion of Tregs was lower than that of T2DM group. There was a negative correlation between the Th1/Th2 ratio and eGFR, and a positive correlation between the proportion of Tregs and eGFR. Multiple linear regression analysis revealed that systolic blood pressure, Tregs, Th1/Th2 ratio and total cholesterol were risk factor for eGFR in patients with T2DM. 
Conclusion  Imbalance in CD4+T cell homeostasis is present in patients with DKD, which is closely related to the decrease of eGFR level. 

Key words: diabetes mellitus, type 2, diabetic kidney disease, CD4-positive T-lymphocytes