Changes and clinical significance of CD4⁺CD25⁺CD127^- regulatory T cells in Graves disease

Objective To investigate the mechanism of Graves disease by observing the changes of CD4⁺CD25⁺CD127^- regulatory T cells (Treg) population in the patients.

Methods Flow cytometry was used to detect the proportion of CD4⁺CD25⁺CD127^- Treg of CD4⁺ T cells in 90 Graves disease patients (Graves disease group) and 50 healthy adults(control group). Thyroid function and autoantibody levels were determined simultaneously. The t test was adopted for comparison between groups. The relationship between CD4⁺CD25⁺CD127^- Treg and thyroid function was analyzed by linear correlation analysis.

Results The percentages of CD4⁺CD25⁺CD127^-Treg in Graves disease group and control group were 1.39%±1.09% and 4.59%±1.14% separately. There was significant difference between the two groups(t=16.4, P < 0.01). There were negative correlation between CD4⁺CD25⁺CD127^- Treg percentages and total triiodothyronine, total thyroxine, free triiodothyronine, free thyroxine and thyrotropin receptor antibody, thyroglobulin antibody, thyroid microsomal antibody(r=-0.62, -0.65, -0.56, -0.71, -0.50, -0.15, all P < 0.01).

Conclusions The reduction of CD4⁺CD25⁺CD127^-Treg percentages in Graves disease group and close relations of CD4⁺CD25⁺CD127^-Treg with thyroid function and thyroid autoantibody levels suggest that CD4⁺CD25⁺CD127^-Treg decrease in the number may be associated with the onset of Graves disease. CD4⁺CD25⁺CD127^- may be the specific marker of Treg.