Imbalance of different types of CD4+forkhead box protein 3 (FoxP3)+ T cells in patients with new‐onset systemic lupus erythematosus

The aim of this study was to examine the numbers of CD4⁺CD25^?forkhead box protein 3 (FoxP3)⁺, CD4⁺CD25⁺FoxP3⁺ and CD4⁺CXCR5⁺FoxP3⁺ T cells in patients with new-onset systemic lupus erythematosus (SLE). The numbers of CD4⁺CD25^?FoxP3⁺, CD4⁺CD25⁺FoxP3⁺ and CD4⁺CXCR5⁺FoxP3⁺ T cells and the concentrations of serum interleukin (IL)-10 in 23 patients and 20 healthy controls (HC) were measured. The potential correlations between CD4⁺FoxP3⁺ T cells, serum IL-10 and clinical measures in SLE patients were analysed. In comparison with that in the HC, significantly reduced numbers of CD4⁺CD25⁺FoxP3⁺ and CD4⁺CXCR5⁺FoxP3⁺ T cells, but increased numbers of CD4⁺CD25^?FoxP3⁺ T cells, were detected, accompanied by significantly lower levels of serum IL-10 in the patients. Stratification analysis indicated the numbers of CD4⁺CD25⁺FoxP3⁺ and CD4⁺CXCR5⁺FoxP3⁺ T cells and serum IL-10 levels in the patients with seropositive anti-dsDNA were significantly less than that in those with seronegative anti-dsDNA. Treatment with the anti-SLE therapy, particularly with prednisone, leflunomide and methotrexate, significantly improved the imbalance of these types of FoxP3⁺ T cells and increased the concentrations of serum IL-10 in the drug-responding patients. The numbers of CD4⁺CD25⁺FoxP3⁺ T cells were correlated negatively with the values of SLE disease activity index (SLEDAI), whereas the numbers of CD4⁺CD25^?FoxP3⁺ T cells were correlated positively with the values of SLEDAI, erythrocyte sedimentation rate (ESR) and serum C3. In addition, the concentrations of serum IL-10 were correlated positively with the numbers of CD4⁺CD25⁺FoxP3⁺ T cells, but negatively with the values of SLEDAI, serum C3, CRP and ESR in these patients. Our data indicate that the imbalance of different types of FoxP3⁺CD4⁺ T cells may contribute to the development of SLE in Chinese patients.