Aim: To explore the frequencies of peripheral blood CD4(+);CD25(high);Treg and CD4(+);CD25(low);T cells and the expression of the co-stimulatory molecule PD-1 on these two group cells surface in SLE and RA patients, and to explore their roles in cell immunity disorder of SLE and RA.
Methods: Flow cytometry (FCM) was used to determine the frequencies of peripheral blood CD4(+);CD25(high);Treg and CD4(+);CD25(low);T cells, and the expression percentage of PD-1.
Results: Compared with healthy control, the frequencies of peripheral blood CD4(+);CD25(high);Treg from both SLE and RA patients groups decreased significantly(P<0.05). Compared between two disease groups, the frequency of peripheral blood CD4(+);CD25(high);Treg in SLE patients was significantly lower(P<0.05). The expression percentage of PD-1 on CD4(+);CD25(high);Treg surface in RA group was obviously lower than that in both healthy control and SLE patients groups(P<0.05), while the percentage had no significant difference between SLE patients and healthy control(P>0.05). There was no significant difference in both the frequency of CD4(+);CD25(low);T cells and the expression percentage of PD-1 on this subset cells among three groups.
Conclusion: The weakened ability of peripheral blood CD4(+);CD25(high);Treg to suppress effector T cells resulted from their production deficiency is the common characteristic of SLE and RA patients. Decreased expression of PD-1 is the primary cause leading to the suppressive function of peripheral blood CD4(+);CD25(high);Treg weakened in RA patients. However, PD-1 does not play major role in weakening the suppression activity of CD4(+);CD25(high);Treg from SLE patients.