Fig. 1.

Fluorescence activated cell sorter (FACS) analysis of circulating CD4⁺forkhead box protein 3 (FoxP3)⁺ T cells. Peripheral blood mononuclear cells (PBMCs) from individual systemic lupus erythematosus (SLE) patients and healthy control (HC) subjects were stained with phycoerythrin (PE)-cyanin 7 (Cy7)-anti-CD4 and Alexafluor647-anti-CXCR5, peridinin chlorophyll (PerCP)-anti-CD4 and fluorescein isothiocyanate (FITC)-anti-CD25 or isotype controls, fixed and permeabilized, followed by intracellular staining with PE-anti-FoxP3. The frequency of total CD4⁺, CD4⁺CD25^-FoxP3⁺, CD4⁺CD25⁺FoxP3⁺, and CD4⁺CXCR5⁺FoxP3⁺ T cells was determined by flow cytometry analysis. The cells were gated on living lymphocytes and then gated on CD4⁺ cells, and at least about 30 000 events were analysed for each sample. The numbers of each type of CD4⁺FoxP3⁺ T cells were calculated, according to the total numbers of PBMCs, the frequency of total CD4⁺ and different types of CD4⁺FoxP3⁺ T cells. The concentrations of serum interleukin (IL)-10 in individual subjects were determined by enzyme-linked immunosorbent assay (ELISA). (a) Representative charts of flow cytometry analysis. (b) Quantitative analysis. Data shown are representative FACS charts or the mean numbers of each type of cells per ml of peripheral blood and the mean levels of serum IL-10 in individual subjects from two separate experiments. The horizontal lines indicate the median values for each group.