Figure 1

Strategy for flow cytometric determination of Treg frequencies. Treg frequencies in peripheral blood of patients and controls were determined by flow cytometry. Lymphocytes (A) were identified based on their forward (FSC) and side scatter characteristic (SSC). Within the lymphocyte population, CD4⁺CD8^neg cells were gated (B) and the subpopulation of CD25^highFOXP3⁺ cells quantitated in a dotplot showing CD25 versus FOXP3 expression (C).