Abstract

Objective: To investigate the expressions of Foxp3 and CD25 on CD4⁺ T cells from patients with new-onset systemic lupus erythematosus (SLE) and assess their clinical significance.

Methods: 10 patients with active (systemic lupus erythematosus Disease Activity Index (SLEDAI) ⩾10) and 11 with inactive (SLEDAI ⩽5) new-onset SLE as well as 11 healthy volunteers were enrolled. The expressions of CD25, Foxp3 and CD127 on CD4⁺ T cells were analysed by flow cytometry. Proliferation assays were performed on isolated CD4⁺CD25⁺ or CD4⁺CD25⁻ T cells, or both.

Results: There was no significant difference in the number of CD4⁺CD25⁺Foxp3⁺ T cells in subjects with either active or inactive SLE compared with normal controls (p>0.05). Moreover, the suppressive capacity of CD4⁺CD25⁺ T cells in patients with new-onset lupus was not impaired as measured by the ability to inhibit proliferation of CD4⁺CD25⁻ T cells. Interestingly, CD4⁺CD25⁻Foxp3⁺ T cells in new-onset lupus (2.97–10.94%) were significantly more frequent than in normal controls (1.01–3.62%) (p<0.01), and correlated positively with the titres of anti-dsDNA antibodies (p = 0.029). Few of these cells expressed CD127. Treatment with glucocorticoids and cyclophosphamide reduced CD4⁺CD25⁻Foxp3⁺ T cells in 8 of 10 patients with active disease.

Conclusions: There was a significant increase in CD4⁺CD25⁻Foxp3⁺ T cells in patients with new-onset SLE that correlated with anti-dsDNA titres, whereas no alteration in either the percentage or function of CD4⁺CD25⁺Foxp3⁺ T cells was observed.