Representative flow cytometric analysis of FOXP3⁺ cells. Staining for FOXP3⁺ cells on peripheral blood lymphocytes (A,B,D,E) or duodenal lymphocytes (C,F) obtained from an untreated HIV-infected patient. Cells were gated for CD4⁺ lymphocytes (A-C) or for lymphocytes in the forward-sideward scatter (D-F). Numbers indicate the frequency of FOXP3⁺CD25^high cells (A-C) or the frequency of cells in each quadrant (D-F).