CD4 and neoplasm: In conclusion, the presence of high percentages of CD4+CD25hiFoxP3+ T cells in the MLTC cultures suppresses the capacity of tumor-reactive T cells to proliferate upon stimulation with autologous tumor cells, but the specific depletion of CD4+CD25hiFoxP3+ T cells using fully GMP-compliant procedures and CD25-specific or CD4-specific antibodies is not robust enough to guarantee good tumor-reactive T cell expansions during MLTC.