Representative two-color dot plots (anti-IL-4 PE versus anti-IFN-γ FITC) from analysis of intracellular cytokines by flow cytometry. Peripheral whole blood samples obtained from individuals were cultured for 4 hours with PMA and ionomycin in the presence of brefeldin A. The activated cells were fixed and stained with anti IFN-γ FITC, anti-IL-4 PE, and CD4-PerCP. The cells were then subjected to flow cytometric analysis on a FACScan flow cytometer (Becton Dickinson). Dot plots (a) and (b) are typical examples of FACS histograms which have demonstrated contrastive polarization to the Th1- and Th2-like cytokine responses, respectively. (a) histogram for one SLE patient (age/sex; 48/F) with DPLN. (b) histogram for another SLE patient (age/sex; 21/F) with MLN. The percentage of cells in each of the quadrants are shown in the right upper corners. The values of the Th1/Th2 ratio are shown in the top of each panel.
