Fig. 4.

Flow cytometric analysis before and after depletion of T regulatory cells (T_reg) from tuberculosis (TB) patients' peripheral blood mononuclear cells (PBMC). TB patients' PBMC were stained with CD4 and CD25 before (a) and after (c) depletion of T_reg. CD39 expression was evaluated on gated CD4⁺CD25^high T cells (b). Fluorescence activated cell sorter (FACS) analysis was performed as described in the Materials and methods section. Representative panels from one patient are shown. The percentage of T_reg evaluated as CD4⁺CD25^high in T_reg-undepleted PBMC is 2% (a). Among them 88% are CD39⁺ (b). After T_reg depletion the percentage of T_reg is 0·2% (c).