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.
10 patients with active (systemic lupus erythematosus Disease Activity Index (SLEDAI) >or=10) and 11 with inactive (SLEDAI <or=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.
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.
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.