Combination of RAPA + IL-2 results in the expansion of donor-type CD4⁺Foxp3⁺ Tregs in the LNs, CD4⁺CD25⁺ T cells in peripheral tissues, and reduces CD4⁺CD25⁻ T cells. BALB/c mice (Thy-1.2 and H-2k^d) were injected with 5 × 10⁶ TCD-BM cells (Thy-1.2 and H-2k^b) and 1 × 10⁶ Tcons (Thy-1.1 and H-2k^b) from C57BL/6 mice after lethal irradiation with 800 cGy on day 0. Mice in each group received PBS, RAPA, IL2 or a combination of RAPA plus IL-2 from day 0 to day 7 after BMT. Flow cytometry of the CD4 T-cell population and intracellular staining of Foxp3 (A) or CD25 (B,C) in total lymphocytes by gating Thy-1.1⁺ from LNs and spleen of BALB/c mice on day 7 after BMT was performed (3 mice in each group). The bar graphs compare the proportion of CD4⁺Foxp3⁺ cells (D), CD4⁺CD25⁺ T cells (E) and CD4⁺CD25⁻ T cells (F) in LNs of each group. Data are derived from 3 independent experiments. *P < .05. Results were shown as mean ± SD.