Abstract:Objective:To analyze the association of three kinds of Tregs labeled by CD4+CD25High, CD4+CD25+CD127Low/-, CD4+CD25+FoxP3+ and study the effect of different fluorescence labeling methods on Tregs identification. Methods: Sixty samples of the peripheral blood from 60 healthy people were randomly divided into 2 groups (group I and group Ⅱ). Group I was labeled by CD25-APC/CD127-PE/CD4-FITC, group Ⅱ was labeled by CD25-PE/CD127-Alexa Fluor■647/CD4-PerCP-Cy5.5. Another 10 samples from group I were labeled by CD25-FITC/FoxP3-PE/CD4-PerCP-Cy5.5/CD127-Alexa Fluor■647. All labeled samples were detected using flow cytometry, and the data were analyzed using CellQuest software to count the numbers of Tregs labeled with different methods, and then the relationships between them were analyzed. Results: CD25+CD127Low/- Tregs cells in group Ⅱ (7.89 ± 1.37)% was significantly higher than that in group Ⅰ (6.37 ± 1.83)%(P = 0.001). The correlation coefficient (r) of CD4+CD25High and CD4+CD25+CD127Low/- in the two group were 0.944 and 0.916, respectively;(94.08 ± 1.93)% of CD25+FoxP3+ cells were also labeled with low CD127 expression, there was a high correlation (r=0.846) and no significant difference (P=0.774)between them. Conclusion: CD25+CD127Low/- can specifically label Tregs, and is suitable for clinical application. Between the labellings with FoxP3 and CD25-APC/CD127-PE/CD4-FITC fluorescein combination, there is a high correlation to identify Tregs in the peripheral blood.